diff --git a/application/clicommands/CheckCommand.php b/application/clicommands/CheckCommand.php
index 33d09dc0..0485b144 100644
--- a/application/clicommands/CheckCommand.php
+++ b/application/clicommands/CheckCommand.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Clicommands;
 
+use Exception;
 use gipfl\Cli\Screen;
 use Icinga\Date\DateFormatter;
 use Icinga\Exception\NotFoundError;
@@ -12,10 +13,10 @@
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\Db\CheckRelatedLookup;
 use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
-use Icinga\Module\Vspheredb\Monitoring\CheckPluginState;
 use Icinga\Module\Vspheredb\Monitoring\CheckRunner;
 use Icinga\Module\Vspheredb\Monitoring\Health\ServerConnectionInfo;
 use Icinga\Module\Vspheredb\Monitoring\Health\VCenterInfo;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
 use InvalidArgumentException;
 use Ramsey\Uuid\Uuid;
 
@@ -28,18 +29,20 @@ class CheckCommand extends Command
 {
     use CheckPluginHelper;
 
-    /** @var Db */
-    protected $db;
+    protected ?Db $db = null;
 
     /**
      * Check vSphereDB daemon health
+     *
+     * @return void
      */
-    public function healthAction()
+    public function healthAction(): void
     {
         $this->run(function () {
             $migrations = Db::migrationsForDb($this->db());
             if (! $migrations->hasSchema()) {
                 $this->addProblem('CRITICAL', 'Database has no vSphereDB schema');
+
                 return resolve(null);
             }
             if ($migrations->hasPendingMigrations()) {
@@ -57,15 +60,15 @@ public function healthAction()
                 }
 
                 if (count($vCenters) > 1) {
-                    if ($this->getState() === 0) {
-                        $this->prependMessage('All vCenters/ESXi Hosts are connected');
-                    } else {
-                        $this->prependMessage('There are problems with some vCenters/ESXi Host connections');
-                    }
+                    $this->prependMessage(
+                        $this->getState() === 0
+                            ? 'All vCenters/ESXi Hosts are connected'
+                            : 'There are problems with some vCenters/ESXi Host connections'
+                    );
                 }
-            }, function (\Exception $e) {
+            }, function (Exception $e) {
                 $message = $e->getMessage();
-                if (preg_match('/^Unable to connect/', $message)) {
+                if (str_starts_with($message, 'Unable to connect')) {
                     $message = "Daemon not running? $message";
                 }
                 $this->addProblem('CRITICAL', $message);
@@ -82,8 +85,10 @@ public function healthAction()
      * USAGE
      *
      * icingacli vspheredb check vcenterconnection --vCenter <id>
+     *
+     * @return void
      */
-    public function vcenterconnectionAction()
+    public function vcenterconnectionAction(): void
     {
         $this->run(function () {
             $vcenter = VCenterInfo::fetchOne(
@@ -105,20 +110,16 @@ public function vcenterconnectionAction()
      * USAGE
      *
      * icingacli vspheredb check host [--name <name>|--uuid <uuid>] [--ruleset <set>] [--rule [<ruleset>/]<rule>]
+     *
+     * @return void
      */
-    public function hostAction()
+    public function hostAction(): void
     {
         $this->run(function () {
             $uuid = $this->params->get('uuid');
-            if ($uuid !== null) {
-                $params = [
-                    'uuid' => Uuid::fromString($uuid)->getBytes()
-                ];
-            } else {
-                $params = [
-                    'host_name' => $this->params->getRequired('name')
-                ];
-            }
+            $params = $uuid !== null
+                ? ['uuid' => Uuid::fromString($uuid)->getBytes()]
+                : ['host_name' => $this->params->getRequired('name')];
             $host = $this->lookup()->findOneBy('HostSystem', $params);
             $this->runChecks($host);
         });
@@ -130,8 +131,10 @@ public function hostAction()
      * USAGE
      *
      * icingacli vspheredb check hosts
+     *
+     * @return void
      */
-    public function hostsAction()
+    public function hostsAction(): void
     {
         $this->showOverallStatusForProblems(
             $this->lookup()->listNonGreenObjects('HostSystem')
@@ -144,8 +147,10 @@ public function hostsAction()
      * USAGE
      *
      * icingacli vspheredb check vm [--name <name>|--uuid <uuid>] [--ruleset <set>] [--rule [<ruleset>/]<rule>]
+     *
+     * @return void
      */
-    public function vmAction()
+    public function vmAction(): void
     {
         $this->run(function () {
             $uuid = $this->params->get('uuid');
@@ -174,8 +179,10 @@ public function vmAction()
      * USAGE
      *
      * icingacli vspheredb check vms
+     *
+     * @return void
      */
-    public function vmsAction()
+    public function vmsAction(): void
     {
         $this->showOverallStatusForProblems(
             $this->lookup()->listNonGreenObjects('VirtualMachine')
@@ -188,20 +195,16 @@ public function vmsAction()
      * USAGE
      *
      * icingacli vspheredb check datastore [--name <name>|--uuid <uuid>] [--ruleset <set>] [--rule [<ruleset>/]<rule>]
+     *
+     * @return void
      */
-    public function datastoreAction()
+    public function datastoreAction(): void
     {
         $this->run(function () {
             $uuid = $this->params->get('uuid');
-            if ($uuid !== null) {
-                $params = [
-                    'uuid' => Uuid::fromString($uuid)->getBytes()
-                ];
-            } else {
-                $params = [
-                    'object_name' => $this->params->getRequired('name')
-                ];
-            }
+            $params = $uuid !== null
+                ? ['uuid' => Uuid::fromString($uuid)->getBytes()]
+                : ['object_name' => $this->params->getRequired('name')];
             $datastore = $this->lookup()->findOneBy('Datastore', $params);
             $this->runChecks($datastore);
         });
@@ -213,15 +216,22 @@ public function datastoreAction()
      * USAGE
      *
      * icingacli vspheredb check datastores
+     *
+     * @return void
      */
-    public function datastoresAction()
+    public function datastoresAction(): void
     {
         $this->showOverallStatusForProblems(
             $this->lookup()->listNonGreenObjects('Datastore')
         );
     }
 
-    protected function runChecks(BaseDbObject $object)
+    /**
+     * @param BaseDbObject $object
+     *
+     * @return never
+     */
+    protected function runChecks(BaseDbObject $object): never
     {
         $runner = new CheckRunner($this->db());
         if ($section = $this->params->get(CheckRunner::RULESET_NAME_PARAMETER)) {
@@ -244,10 +254,19 @@ protected function runChecks(BaseDbObject $object)
         }
         $result = $runner->check($object);
         echo $this->colorizeOutput($result->getOutput()) . PHP_EOL;
+
         exit($result->getState()->getExitCode());
     }
 
-    protected static function assertString($string, string $label)
+    /**
+     * @param mixed $string
+     * @param string $label
+     *
+     * @return void
+     *
+     * @throws InvalidArgumentException
+     */
+    protected static function assertString(mixed $string, string $label): void
     {
         if (! is_string($string)) {
             throw new InvalidArgumentException("$label must be a string");
@@ -257,9 +276,10 @@ protected static function assertString($string, string $label)
     /**
      * @param VCenterInfo $vcenter
      * @param array<int, array<int, ServerConnectionInfo>> $connections
+     *
      * @return void
      */
-    protected function checkVCenterConnection(VCenterInfo $vcenter, array $connections)
+    protected function checkVCenterConnection(VCenterInfo $vcenter, array $connections): void
     {
         $vcenterId = $vcenter->id;
         $prefix = sprintf('%s, %s: ', $vcenter->name, $vcenter->software);
@@ -282,7 +302,10 @@ protected function checkVCenterConnection(VCenterInfo $vcenter, array $connectio
         }
     }
 
-    protected function checkDaemonStatus()
+    /**
+     * @return void
+     */
+    protected function checkDaemonStatus(): void
     {
         $db = $this->db()->getDbAdapter();
         $daemon = $db->fetchRow(
@@ -301,16 +324,26 @@ protected function checkDaemonStatus()
         }
     }
 
+    /**
+     * @param string $string
+     *
+     * @return string
+     */
     protected function colorizeOutput(string $string): string
     {
         $screen = Screen::factory();
         $pattern = '/\[(OK|WARNING|CRITICAL|UNKNOWN)]\s/';
         return preg_replace_callback($pattern, function ($match) use ($screen) {
-            return '[' . $screen->colorize($match[1], (new CheckPluginState($match[1]))->getColor()) . '] ';
+            return '[' . $screen->colorize($match[1], CheckPluginState::from($match[1])->color()) . '] ';
         }, $string);
     }
 
-    protected function showOverallStatusForProblems($problems)
+    /**
+     * @param array $problems
+     *
+     * @return void
+     */
+    protected function showOverallStatusForProblems(array $problems): void
     {
         $this->run(function () use ($problems) {
             if (empty($problems)) {
@@ -324,7 +357,13 @@ protected function showOverallStatusForProblems($problems)
         });
     }
 
-    protected function addProblematicObjectNames($color, $objects)
+    /**
+     * @param string $color
+     * @param array $objects
+     *
+     * @return void
+     */
+    protected function addProblematicObjectNames(string $color, array $objects): void
     {
         $showMax = 5;
         $stateName = $this->getStateForColor($color);
@@ -357,27 +396,26 @@ protected function addProblematicObjectNames($color, $objects)
      */
     protected function getStateForColor(string $color): string
     {
-        $colors = [
-            'green'  => 'OK',
-            'gray'   => 'CRITICAL',
-            'yellow' => 'WARNING',
-            'red'    => 'CRITICAL',
-        ];
-
-        return $colors[$color];
+        return match ($color) {
+            'green'       => 'OK',
+            'gray', 'red' => 'CRITICAL',
+            'yellow'      => 'WARNING'
+        };
     }
 
+    /**
+     * @return CheckRelatedLookup
+     */
     protected function lookup(): CheckRelatedLookup
     {
         return new CheckRelatedLookup($this->db());
     }
 
+    /**
+     * @return Db
+     */
     protected function db(): Db
     {
-        if ($this->db === null) {
-            $this->db = Db::newConfiguredInstance();
-        }
-
-        return $this->db;
+        return $this->db ??= Db::newConfiguredInstance();
     }
 }
diff --git a/application/clicommands/Command.php b/application/clicommands/Command.php
index 3b01416c..e6fe3499 100644
--- a/application/clicommands/Command.php
+++ b/application/clicommands/Command.php
@@ -15,30 +15,36 @@
 use Icinga\Module\Vspheredb\Configuration;
 use Icinga\Module\Vspheredb\Daemon\RemoteClient;
 use React\EventLoop\Loop;
+use React\EventLoop\LoopInterface;
 use React\Stream\WritableResourceStream;
 
 class Command extends CliCommand
 {
-    private $loopStarted = false;
+    private bool $loopStarted = false;
 
-    protected $logger;
+    protected ?Logger $logger = null;
 
-    /** @var RemoteClient */
-    protected $remoteClient;
+    protected ?RemoteClient $remoteClient = null;
 
-    public function init()
+    public function init(): void
     {
         $this->app->getModuleManager()->loadEnabledModules();
         $this->clearProxySettings();
         $this->initializeLogger();
     }
 
-    protected function loop()
+    /**
+     * @return LoopInterface
+     */
+    protected function loop(): LoopInterface
     {
         return Loop::get();
     }
 
-    protected function eventuallyStartMainLoop()
+    /**
+     * @return $this
+     */
+    protected function eventuallyStartMainLoop(): static
     {
         if (! $this->loopStarted) {
             $this->loopStarted = true;
@@ -48,7 +54,10 @@ protected function eventuallyStartMainLoop()
         return $this;
     }
 
-    protected function stopMainLoop()
+    /**
+     * @return $this
+     */
+    protected function stopMainLoop(): static
     {
         if ($this->loopStarted) {
             $this->loopStarted = false;
@@ -61,16 +70,15 @@ protected function stopMainLoop()
     /**
      * @return RemoteClient
      */
-    protected function remoteClient()
+    protected function remoteClient(): RemoteClient
     {
-        if ($this->remoteClient === null) {
-            $this->remoteClient = new RemoteClient(Configuration::getSocketPath(), $this->loop());
-        }
-
-        return $this->remoteClient;
+        return $this->remoteClient ??= new RemoteClient(Configuration::getSocketPath(), $this->loop());
     }
 
-    protected function initializeLogger()
+    /**
+     * @return void
+     */
+    protected function initializeLogger(): void
     {
         $this->logger = $logger = new Logger();
         $this->eventuallyFilterLog($this->logger);
@@ -91,7 +99,12 @@ protected function initializeLogger()
         }
     }
 
-    protected function eventuallyFilterLog(Logger $logger)
+    /**
+     * @param Logger $logger
+     *
+     * @return void
+     */
+    protected function eventuallyFilterLog(Logger $logger): void
     {
         /** @noinspection PhpStatementHasEmptyBodyInspection */
         if ($this->isDebugging) {
@@ -104,18 +117,24 @@ protected function eventuallyFilterLog(Logger $logger)
         }
     }
 
-    protected function isRpc()
+    /**
+     * @return bool
+     */
+    protected function isRpc(): bool
     {
         return (bool) $this->params->get('rpc');
     }
 
-    protected function clearProxySettings()
+    /**
+     * @return void
+     */
+    protected function clearProxySettings(): void
     {
         $settings = [
             'http_proxy',
             'https_proxy',
             'HTTPS_PROXY',
-            'ALL_PROXY',
+            'ALL_PROXY'
         ];
         foreach ($settings as $setting) {
             putenv("$setting=");
@@ -124,11 +143,13 @@ protected function clearProxySettings()
 
     /**
      * @param string $msg
+     *
      * @return never-return
      */
     public function fail($msg)
     {
         echo $this->screen->colorize("$msg\n", 'red');
+
         exit(1);
     }
 
@@ -136,13 +157,16 @@ protected function requireExtension()
     {
     }
 
-    public function failFriendly($task, $error = 'unknown error', $subject = null)
+    /**
+     * @param string $task
+     * @param Exception|string $error
+     * @param ?string $subject
+     *
+     * @return void
+     */
+    public function failFriendly(string $task, Exception|string $error = 'unknown error', ?string $subject = null): void
     {
-        if ($error instanceof Exception) {
-            $message = $error->getMessage();
-        } else {
-            $message = $error;
-        }
+        $message = $error instanceof Exception ? $error->getMessage() : $error;
 
         if (!$this->isRpc()) {
             $this->fail($message);
@@ -158,12 +182,19 @@ public function failFriendly($task, $error = 'unknown error', $subject = null)
         // This allows to flush streams, especially pending log messages
         $this->loop()->addTimer(0.1, function () {
             $this->stopMainLoop();
+
             exit(1);
         });
         $this->eventuallyStartMainLoop();
     }
 
-    protected function shorten($message, $length)
+    /**
+     * @param string $message
+     * @param int $length
+     *
+     * @return string
+     */
+    protected function shorten(string $message, int $length): string
     {
         if (strlen($message) > $length) {
             return substr($message, 0, $length - 2) . '...';
@@ -172,7 +203,12 @@ protected function shorten($message, $length)
         return $message;
     }
 
-    protected function requiredParam($name)
+    /**
+     * @param string $name
+     *
+     * @return mixed
+     */
+    protected function requiredParam(string $name): mixed
     {
         $value = $this->params->get($name);
         if ($value === null) {
diff --git a/application/clicommands/DaemonCommand.php b/application/clicommands/DaemonCommand.php
index 6cb56cb6..3de0a767 100644
--- a/application/clicommands/DaemonCommand.php
+++ b/application/clicommands/DaemonCommand.php
@@ -14,8 +14,10 @@ class DaemonCommand extends Command
      * USAGE
      *
      * icingacli vsphere daemon run [--verbose|--debug]
+     *
+     * @return void
      */
-    public function runAction()
+    public function runAction(): void
     {
         $this->assertRequiredExtensionsAreLoaded();
         $this->assertNoVcenterParam();
@@ -30,7 +32,10 @@ public function runAction()
         $this->eventuallyStartMainLoop();
     }
 
-    protected function assertNoVcenterParam()
+    /**
+     * @return void
+     */
+    protected function assertNoVcenterParam(): void
     {
         if ($this->params->get('vCenterId')) {
             $this->fail(
@@ -40,7 +45,10 @@ protected function assertNoVcenterParam()
         }
     }
 
-    protected function assertRequiredExtensionsAreLoaded()
+    /**
+     * @return void
+     */
+    protected function assertRequiredExtensionsAreLoaded(): void
     {
         $required = ['soap', 'posix', 'pcntl'];
         $missing = [];
diff --git a/application/clicommands/DbCommand.php b/application/clicommands/DbCommand.php
index 8e7c7a11..67c9e8b9 100644
--- a/application/clicommands/DbCommand.php
+++ b/application/clicommands/DbCommand.php
@@ -7,6 +7,7 @@
 use gipfl\Log\IcingaWeb\IcingaLogger;
 use gipfl\Log\Logger;
 use gipfl\Log\Writer\JsonRpcConnectionWriter;
+use gipfl\Protocol\JsonRpc\Handler\JsonRpcHandler;
 use gipfl\Protocol\JsonRpc\Handler\NamespacedPacketHandler;
 use gipfl\Protocol\JsonRpc\JsonRpcConnection;
 use gipfl\Protocol\NetString\StreamWrapper;
@@ -20,7 +21,10 @@
  */
 class DbCommand extends Command
 {
-    public function runAction()
+    /**
+     * @return void
+     */
+    public function runAction(): void
     {
         if (!$this->isRpc()) {
             $this->fail('This is an internal command and should not be called directly');
@@ -45,18 +49,27 @@ public function runAction()
         $this->loop()->run();
     }
 
-    protected function prepareLogger()
+    /**
+     * @return Logger
+     */
+    protected function prepareLogger(): Logger
     {
         $logger = new Logger();
         $this->eventuallyFilterLog($logger);
         IcingaLogger::replace($logger);
+
         return $logger;
     }
 
     /**
      * Prepares a JSON-RPC Connection on STDIN/STDOUT
+     *
+     * @param LoopInterface $loop
+     * @param JsonRpcHandler $handler
+     *
+     * @return JsonRpcConnection
      */
-    protected function prepareJsonRpc(LoopInterface $loop, $handler)
+    protected function prepareJsonRpc(LoopInterface $loop, JsonRpcHandler $handler): JsonRpcConnection
     {
         return new JsonRpcConnection(new StreamWrapper(
             new ReadableResourceStream(STDIN, $loop),
diff --git a/application/clicommands/HealthCommand.php b/application/clicommands/HealthCommand.php
index 45019024..741f81a7 100644
--- a/application/clicommands/HealthCommand.php
+++ b/application/clicommands/HealthCommand.php
@@ -8,7 +8,10 @@ class HealthCommand extends Command
 {
     use CheckPluginHelper;
 
-    public function checkAction()
+    /**
+     * @return void
+     */
+    public function checkAction(): void
     {
         $this->run(function () {
             $this->addProblem('UNKNOWN', 'Please use `icingacli vspheredb check vcenterconnection`');
diff --git a/application/clicommands/MigrationCommand.php b/application/clicommands/MigrationCommand.php
index 89ce052a..9afbc944 100644
--- a/application/clicommands/MigrationCommand.php
+++ b/application/clicommands/MigrationCommand.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Clicommands;
 
+use gipfl\DbMigration\Migrations;
 use Icinga\Module\Vspheredb\Db;
 
 /**
@@ -25,8 +26,10 @@ class MigrationCommand extends Command
      *
      * Exit code 0 means that there are pending migrations, code 1 that there
      * are no such. Use --verbose for human-readable output
+     *
+     * @return never
      */
-    public function pendingAction()
+    public function pendingAction(): never
     {
         if ($count = $this->migrations()->countPendingMigrations()) {
             if ($this->isVerbose) {
@@ -51,14 +54,20 @@ public function pendingAction()
      * Run any pending migrations
      *
      * All pending migrations will be silently applied
+     *
+     * @return never
      */
-    public function runAction()
+    public function runAction(): never
     {
         $this->migrations()->applyPendingMigrations();
+
         exit(0);
     }
 
-    protected function migrations()
+    /**
+     * @return Migrations
+     */
+    protected function migrations(): Migrations
     {
         return Db::migrationsForDb(Db::newConfiguredInstance());
     }
diff --git a/application/clicommands/PerfCommand.php b/application/clicommands/PerfCommand.php
index 080e65f0..7d44f4d7 100644
--- a/application/clicommands/PerfCommand.php
+++ b/application/clicommands/PerfCommand.php
@@ -5,7 +5,7 @@
 class PerfCommand extends Command
 {
     /**
-     * Deprecated. The main daemon now provides this functionality
+     * @deprecated The main daemon now provides this functionality
      */
     public function influxdbAction()
     {
diff --git a/application/clicommands/PerfdataconsumerCommand.php b/application/clicommands/PerfdataconsumerCommand.php
index 02c8c61e..1df8e63f 100644
--- a/application/clicommands/PerfdataconsumerCommand.php
+++ b/application/clicommands/PerfdataconsumerCommand.php
@@ -2,12 +2,13 @@
 
 namespace Icinga\Module\Vspheredb\Clicommands;
 
+use Exception;
 use gipfl\Translation\StaticTranslator;
 use gipfl\Web\Form;
 use gipfl\ZfDbStore\ZfDbStore;
+use GuzzleHttp\Psr7\ServerRequest;
 use Icinga\Data\ResourceFactory;
 use Icinga\Module\Vspheredb\Web\Form\PerfdataConsumerForm;
-use GuzzleHttp\Psr7\ServerRequest;
 
 class PerfdataconsumerCommand extends Command
 {
@@ -17,8 +18,10 @@ class PerfdataconsumerCommand extends Command
      * USAGE
      *
      * icingacli vspheredb perfdataconsumer create <name> --implementation <name> [--disabled] [--other <settings>]
+     *
+     * @return void
      */
-    public function createAction()
+    public function createAction(): void
     {
         $name = $this->params->shift();
         if (strlen($name) === 0) {
@@ -34,7 +37,7 @@ public function createAction()
             'name'           => $name,
             'enabled'        => $enabled ? 'y' : 'n',
             'implementation' => $implementation,
-            'submit'         => 'Create',
+            'submit'         => 'Create'
         ] + $this->params->getParams();
         if ($this->submitForm($params)) {
             echo "'$name' has been created\n";
@@ -44,7 +47,12 @@ public function createAction()
         $this->fail("Creating '$name' failed for unknown reasons");
     }
 
-    protected function submitForm($params)
+    /**
+     * @param array $params
+     *
+     * @return bool
+     */
+    protected function submitForm(array $params): bool
     {
         StaticTranslator::setNoTranslator();
         $form = new PerfdataConsumerForm($this->loop(), $this->remoteClient(), $this->getStore());
@@ -56,10 +64,16 @@ protected function submitForm($params)
         );
     }
 
-    protected function validateRequestWithForm(ServerRequest $request, Form $form)
+    /**
+     * @param ServerRequest $request
+     * @param Form $form
+     *
+     * @return bool
+     */
+    protected function validateRequestWithForm(ServerRequest $request, Form $form): bool
     {
         $success = false;
-        $form->on($form::ON_SUCCESS, function () use (&$success) {
+        $form->on($form::ON_SUBMIT, function () use (&$success) {
             $success = true;
         });
         $form->handleRequest($request);
@@ -84,18 +98,27 @@ protected function validateRequestWithForm(ServerRequest $request, Form $form)
         return $success;
     }
 
-    protected function wantErrorMessage($message)
+    /**
+     * @param Exception|string $message
+     *
+     * @return string
+     */
+    protected function wantErrorMessage(Exception|string $message): string
     {
-        if ($message instanceof \Exception) {
+        if ($message instanceof Exception) {
             return $message->getMessage();
         }
 
         return $message;
     }
 
-    protected function getStore()
+    /**
+     * @return ZfDbStore
+     */
+    protected function getStore(): ZfDbStore
     {
         $connection = ResourceFactory::create($this->Config()->get('db', 'resource'));
+
         return new ZfDbStore($connection->getDbAdapter());
     }
 }
diff --git a/application/clicommands/VcenterCommand.php b/application/clicommands/VcenterCommand.php
index a4abd415..87ee5210 100644
--- a/application/clicommands/VcenterCommand.php
+++ b/application/clicommands/VcenterCommand.php
@@ -5,7 +5,7 @@
 class VcenterCommand extends Command
 {
     /**
-     * Deprecated
+     * @deprecated Please check documentation
      */
     public function initializeAction()
     {
diff --git a/application/controllers/AlarmsController.php b/application/controllers/AlarmsController.php
index 5922e9da..4bab7a31 100644
--- a/application/controllers/AlarmsController.php
+++ b/application/controllers/AlarmsController.php
@@ -5,21 +5,21 @@
 use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Url;
 use Icinga\Date\DateFormatter;
-use Icinga\Module\Vspheredb\Web\Table\AlarmHistoryTable;
 use Icinga\Module\Vspheredb\Web\Controller;
+use Icinga\Module\Vspheredb\Web\Table\AlarmHistoryTable;
 use Icinga\Module\Vspheredb\Web\Widget\AlarmHeatmap;
 use Icinga\Module\Vspheredb\Web\Widget\CalendarForEvents;
 
 class AlarmsController extends Controller
 {
-    public function init()
+    public function init(): void
     {
         $this->assertPermission('vspheredb/admin');
         parent::init();
         $this->handleTabs();
     }
 
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->actions()->add(Link::create(
             $this->translate('Calendar'),
@@ -27,7 +27,7 @@ public function indexAction()
             $this->url()->getParams()->toArray(false),
             [
                 'class' => 'icon-calendar',
-                'data-base-target' => '_main',
+                'data-base-target' => '_main'
             ]
         ));
         $day = $this->params->shift('day');
@@ -49,7 +49,7 @@ public function indexAction()
         $table->renderTo($this);
     }
 
-    public function heatmapAction()
+    public function heatmapAction(): void
     {
         $this->actions()->add(Link::create(
             $this->translate('Table'),
@@ -57,7 +57,7 @@ public function heatmapAction()
             $this->url()->getParams()->toArray(false),
             [
                 'class' => 'icon-th-list',
-                'data-base-target' => '_main',
+                'data-base-target' => '_main'
             ]
         ));
         $this->addTitle($this->translate('Alarm Heatmap'));
@@ -68,7 +68,10 @@ public function heatmapAction()
         $this->content()->add(new CalendarForEvents($heatMap, $baseUrl, [255, 0, 0]));
     }
 
-    protected function handleTabs()
+    /**
+     * @return void
+     */
+    protected function handleTabs(): void
     {
         $params = [];
         if ($day = $this->params->get('day')) {
diff --git a/application/controllers/AnomaliesController.php b/application/controllers/AnomaliesController.php
index 0b6911d2..8659f8eb 100644
--- a/application/controllers/AnomaliesController.php
+++ b/application/controllers/AnomaliesController.php
@@ -9,7 +9,7 @@
 class AnomaliesController extends Controller
 {
     // TODO: Overbooked datastores
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->assertPermission('vspheredb/admin');
         $this->addSingleTab($this->translate('Anomalies'));
@@ -19,34 +19,25 @@ public function indexAction()
         $this->addTable('guest_ip_address', $this->translate('Guest IP address'));
     }
 
-    protected function addTable($property, $title)
+    /**
+     * @param string $property
+     * @param string $title
+     *
+     * @return void
+     */
+    protected function addTable(string $property, string $title): void
     {
         $table = VmsWithDuplicateProperty::create($this->db(), $property, $title);
 
         $count = count($table);
         if ($count) {
             $this->content()->add([
-                Html::tag(
-                    'h1',
-                    null,
-                    sprintf(
-                        '%d Virtual Machines with duplicate %s',
-                        $count,
-                        $title
-                    )
-                ),
+                Html::tag('h1', null, sprintf('%d Virtual Machines with duplicate %s', $count, $title)),
                 $table
             ]);
         } else {
             $this->content()->add(
-                Html::tag(
-                    'h1',
-                    null,
-                    sprintf(
-                        'There are no Virtual Machines with duplicate %s',
-                        $title
-                    )
-                )
+                Html::tag('h1', null, sprintf('There are no Virtual Machines with duplicate %s', $title))
             );
         }
     }
diff --git a/application/controllers/AsyncControllerHelper.php b/application/controllers/AsyncControllerHelper.php
index 6f50c146..3b98174a 100644
--- a/application/controllers/AsyncControllerHelper.php
+++ b/application/controllers/AsyncControllerHelper.php
@@ -5,16 +5,23 @@
 use Icinga\Module\Vspheredb\Configuration;
 use Icinga\Module\Vspheredb\Daemon\RemoteClient;
 use React\EventLoop\Loop;
+use React\EventLoop\LoopInterface;
 
 use function React\Async\await;
 use function React\Promise\Timer\timeout;
 
 trait AsyncControllerHelper
 {
-    /** @var RemoteClient */
-    protected $remoteClient;
+    protected ?RemoteClient $remoteClient = null;
 
-    protected function syncRpcCall($method, $params = [], $timeout = 30)
+    /**
+     * @param string $method
+     * @param array $params
+     * @param ?float $timeout
+     *
+     * @return mixed
+     */
+    protected function syncRpcCall(string $method, array $params = [], ?float $timeout = 30): mixed
     {
         return await(timeout($this->remoteClient()->request($method, $params), $timeout));
     }
@@ -22,16 +29,15 @@ protected function syncRpcCall($method, $params = [], $timeout = 30)
     /**
      * @return RemoteClient
      */
-    protected function remoteClient()
+    protected function remoteClient(): RemoteClient
     {
-        if ($this->remoteClient === null) {
-            $this->remoteClient = new RemoteClient(Configuration::getSocketPath(), $this->loop());
-        }
-
-        return $this->remoteClient;
+        return $this->remoteClient ??= new RemoteClient(Configuration::getSocketPath(), $this->loop());
     }
 
-    protected function loop()
+    /**
+     * @return LoopInterface
+     */
+    protected function loop(): LoopInterface
     {
         return Loop::get();
     }
diff --git a/application/controllers/ComputeClusterController.php b/application/controllers/ComputeClusterController.php
index faf9c1dd..e745f4a6 100644
--- a/application/controllers/ComputeClusterController.php
+++ b/application/controllers/ComputeClusterController.php
@@ -3,23 +3,26 @@
 namespace Icinga\Module\Vspheredb\Controllers;
 
 use Icinga\Authentication\Auth;
+use Icinga\Exception\MissingParameterException;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\DbObject\ComputeCluster;
 use Icinga\Module\Vspheredb\Web\Controller;
 use Icinga\Module\Vspheredb\Web\Table\Objects\HostsTable;
 use Icinga\Module\Vspheredb\Web\Widget\AdditionalTableActions;
 use Icinga\Module\Vspheredb\Web\Widget\ComputeClusterHeader;
 use Icinga\Module\Vspheredb\Web\Widget\Summaries;
+use ipl\Html\Attributes;
 
 class ComputeClusterController extends Controller
 {
     /**
-     * @throws \Icinga\Exception\MissingParameterException
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws MissingParameterException
+     * @throws NotFoundError
      */
-    public function indexAction()
+    public function indexAction(): void
     {
         $computeCluster = $this->addComputeCluster();
-        $this->content()->addAttributes(['class' => 'host-info']);
+        $this->content()->addAttributes(Attributes::create(['class' => 'host-info']));
         $table = new HostsTable($this->db(), $this->url());
         (new AdditionalTableActions($table, Auth::getInstance(), $this->url()))
             ->appendTo($this->actions());
@@ -32,10 +35,11 @@ public function indexAction()
 
     /**
      * @return ComputeCluster
-     * @throws \Icinga\Exception\MissingParameterException
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @throws MissingParameterException
+     * @throws NotFoundError
      */
-    protected function addComputeCluster()
+    protected function addComputeCluster(): ComputeCluster
     {
         $computeCluster = ComputeCluster::loadWithUuid($this->params->getRequired('uuid'), $this->db());
         $this->getRestrictionHelper()->assertAccessToVCenterUuidIsGranted($computeCluster->get('vcenter_uuid'));
@@ -48,9 +52,12 @@ protected function addComputeCluster()
 
     /**
      * @param ComputeCluster $computeCluster
-     * @throws \Icinga\Exception\MissingParameterException
+     *
+     * @return void
+     *
+     * @throws MissingParameterException
      */
-    protected function handleTabs(ComputeCluster $computeCluster)
+    protected function handleTabs(ComputeCluster $computeCluster): void
     {
         $hexId = $this->params->getRequired('uuid');
         $this->tabs()->add('index', [
diff --git a/application/controllers/ConfigurationController.php b/application/controllers/ConfigurationController.php
index 577ce732..cdcde141 100644
--- a/application/controllers/ConfigurationController.php
+++ b/application/controllers/ConfigurationController.php
@@ -2,17 +2,20 @@
 
 namespace Icinga\Module\Vspheredb\Controllers;
 
+use Exception;
 use gipfl\IcingaWeb2\Link;
 use gipfl\Web\Widget\Hint;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\Polling\ApiConnection;
+use Icinga\Module\Vspheredb\Web\Controller;
 use Icinga\Module\Vspheredb\Web\Form\ChooseDbResourceForm;
 use Icinga\Module\Vspheredb\Web\Form\MonitoringConnectionForm;
 use Icinga\Module\Vspheredb\Web\Table\MonitoredObjectMappingTable;
 use Icinga\Module\Vspheredb\Web\Table\Objects\VCenterServersTable;
 use Icinga\Module\Vspheredb\Web\Tabs\ConfigTabs;
-use Icinga\Module\Vspheredb\Web\Controller;
+use Icinga\Security\SecurityException;
 use Icinga\Web\Notification;
+use ipl\Html\Contract\Form;
 use ipl\Html\Html;
 use Ramsey\Uuid\Uuid;
 
@@ -21,13 +24,13 @@ class ConfigurationController extends Controller
     use AsyncControllerHelper;
     use RpcServerUpdateHelper;
 
-    public function init()
+    public function init(): void
     {
         $this->assertPermission('vspheredb/admin');
         parent::init();
     }
 
-    public function databaseAction()
+    public function databaseAction(): void
     {
         $this->addTitle($this->translate('vSphereDB Database Configuration'));
         $this->tabs(new ConfigTabs())->activate('database');
@@ -53,6 +56,7 @@ public function databaseAction()
                     'The database has no vSphereDB schema. Waiting for the Background Daemon'
                     . ' to initialize the database'
                 )));
+
                 return;
             }
 
@@ -61,6 +65,7 @@ public function databaseAction()
                     'The database has pending DB migrations. Please restart the Background'
                     . ' daemon to apply them'
                 )));
+
                 return;
             }
 
@@ -76,9 +81,9 @@ public function databaseAction()
     }
 
     /**
-     * @throws \Icinga\Security\SecurityException
+     * @throws SecurityException
      */
-    public function serversAction()
+    public function serversAction(): void
     {
         $this->tabs(new ConfigTabs($this->db()))->activate('servers');
         $this->setAutorefreshInterval(10);
@@ -91,18 +96,13 @@ public function serversAction()
             $connections = $this->mapServerConnectionsToId($this->syncRpcCall('vsphere.getApiConnections'));
             foreach ($connections as $conns) {
                 foreach ($conns as $conn) {
-                    if (
-                        in_array($conn->state, [
-                        ApiConnection::STATE_INIT,
-                        ApiConnection::STATE_LOGIN,
-                        ])
-                    ) {
+                    if (in_array($conn->state, [ApiConnection::STATE_INIT, ApiConnection::STATE_LOGIN])) {
                         $this->setAutorefreshInterval(5);
                     }
                 }
             }
             $this->setAutorefreshInterval(5);
-        } catch (\Exception $e) {
+        } catch (Exception $e) {
             $connections = null;
             $this->content()->add(
                 Hint::warning($this->translate('Got no connection information. Is the Damon running?'))
@@ -123,7 +123,12 @@ public function serversAction()
         }
     }
 
-    protected function mapServerConnectionsToId($connections)
+    /**
+     * @param mixed $connections
+     *
+     * @return array
+     */
+    protected function mapServerConnectionsToId(mixed $connections): array
     {
         $connectionsByServer = [];
         foreach ((array) $connections as $id => $connection) {
@@ -138,7 +143,7 @@ protected function mapServerConnectionsToId($connections)
         return $connectionsByServer;
     }
 
-    public function monitoringAction()
+    public function monitoringAction(): void
     {
         $this->tabs(new ConfigTabs($this->db()))->activate('monitoring');
         $this->actions()->add(Link::create(
@@ -147,7 +152,7 @@ public function monitoringAction()
             null,
             [
                 'class'            => 'icon-plus',
-                'data-base-target' => '_next',
+                'data-base-target' => '_next'
             ]
         ));
         $this->addTitle($this->translate('Monitoring Integration'));
@@ -159,13 +164,11 @@ public function monitoringAction()
             $this->content()->add($wrapper);
             $table->renderTo($this);
         } else {
-            $this->content()->add(Hint::warning($this->translate(
-                'No integration has been configured'
-            )));
+            $this->content()->add(Hint::warning($this->translate('No integration has been configured')));
         }
     }
 
-    public function monitoringconfigAction()
+    public function monitoringconfigAction(): void
     {
         $id = $this->params->get('id');
         if ($id) {
@@ -182,7 +185,7 @@ public function monitoringconfigAction()
         }
 
         $form = new MonitoringConnectionForm($this->db());
-        $form->on(MonitoringConnectionForm::ON_SUCCESS, function (MonitoringConnectionForm $form) {
+        $form->on(Form::ON_SUBMIT, function (MonitoringConnectionForm $form) {
             // TODO: created, modified, nothing, %s
             // $this->getViewRenderer()->disable();
             $this->redirectNow($this->url()->with('id', $form->getId()));
diff --git a/application/controllers/DaemonController.php b/application/controllers/DaemonController.php
index 0566d15f..faf4b4fa 100644
--- a/application/controllers/DaemonController.php
+++ b/application/controllers/DaemonController.php
@@ -2,26 +2,28 @@
 
 namespace Icinga\Module\Vspheredb\Controllers;
 
+use Exception;
 use gipfl\IcingaWeb2\Icon;
 use gipfl\Json\JsonString;
 use gipfl\Web\Widget\Hint;
 use Icinga\Date\DateFormatter;
-use Icinga\Module\Vspheredb\Web\Form\LogLevelForm;
-use Icinga\Module\Vspheredb\Web\Form\RestartDaemonForm;
 use Icinga\Module\Vspheredb\Format;
 use Icinga\Module\Vspheredb\Web\Controller;
+use Icinga\Module\Vspheredb\Web\Form\LogLevelForm;
+use Icinga\Module\Vspheredb\Web\Form\RestartDaemonForm;
 use Icinga\Module\Vspheredb\Web\Table\VsphereApiConnectionTable;
 use Icinga\Module\Vspheredb\Web\Tabs\MainTabs;
 use Icinga\Module\Vspheredb\WebUtil;
 use Icinga\Web\Notification;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\Html\Table;
 
 class DaemonController extends Controller
 {
     use AsyncControllerHelper;
 
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->assertPermission('vspheredb/admin');
         $this->setAutorefreshInterval(30);
@@ -40,7 +42,10 @@ public function indexAction()
         ]);
     }
 
-    protected function prepareLogSettings()
+    /**
+     * @return ?array
+     */
+    protected function prepareLogSettings(): ?array
     {
         $logLevelForm = new LogLevelForm($this->remoteClient(), $this->loop());
         $logLevelForm->on($logLevelForm::ON_SUCCESS, function () {
@@ -54,7 +59,10 @@ protected function prepareLogSettings()
         return null;
     }
 
-    protected function prepareDaemonInfo()
+    /**
+     * @return Hint|array
+     */
+    protected function prepareDaemonInfo(): Hint|array
     {
         $db = $this->db()->getDbAdapter();
         $daemon = $db->fetchRow(
@@ -70,22 +78,26 @@ protected function prepareDaemonInfo()
                     "Daemon keep-alive is outdated in our database, last refresh was %s",
                     WebUtil::timeAgo($daemon->ts_last_refresh / 1000)
                 ));
-            } else {
-                $restartForm = new RestartDaemonForm($this->remoteClient(), $this->loop());
-                $restartForm->on($restartForm::ON_SUCCESS, function () {
-                    Notification::success('Daemon has been asked to restart');
-                    $this->redirectNow($this->url());
-                });
-                $restartForm->handleRequest($this->getServerRequest());
-
-                return [$restartForm, $this->prepareProcessTable(JsonString::decode($daemon->process_info))];
             }
-        } else {
-            return Hint::error($this->translate('Daemon is either not running or not connected to the Database'));
+            $restartForm = new RestartDaemonForm($this->remoteClient(), $this->loop());
+            $restartForm->on($restartForm::ON_SUBMIT, function () {
+                Notification::success('Daemon has been asked to restart');
+                $this->redirectNow($this->url());
+            });
+            $restartForm->handleRequest($this->getServerRequest());
+
+            return [$restartForm, $this->prepareProcessTable(JsonString::decode($daemon->process_info))];
         }
+
+        return Hint::error($this->translate('Daemon is either not running or not connected to the Database'));
     }
 
-    protected function prepareProcessTable($processes)
+    /**
+     * @param mixed $processes
+     *
+     * @return Table
+     */
+    protected function prepareProcessTable(mixed $processes): Table
     {
         $table = new Table();
         foreach ($processes as $pid => $process) {
@@ -103,7 +115,10 @@ protected function prepareProcessTable($processes)
         return $table;
     }
 
-    protected function prepareLogWindow()
+    /**
+     * @return HtmlElement
+     */
+    protected function prepareLogWindow(): HtmlElement
     {
         $db = $this->db()->getDbAdapter();
         $lineCount = 1000;
@@ -115,20 +130,19 @@ protected function prepareLogWindow()
         $logWindow = Html::tag('div', ['class' => 'logWindow'], $log);
         foreach ($logLines as $line) {
             $ts = $line->ts_create / 1000;
-            if ($ts + 3600 * 16 < time()) {
-                $tsFormatted = DateFormatter::formatDateTime($ts);
-            } else {
-                $tsFormatted = DateFormatter::formatTime($ts);
-            }
-            $log->add(Html::tag('div', [
-                'class' => $line->level
-            ], "$tsFormatted: " . $line->message));
+            $tsFormatted = $ts + 3600 * 16 < time()
+                ? DateFormatter::formatDateTime($ts)
+                : DateFormatter::formatTime($ts);
+            $log->add(Html::tag('div', ['class' => $line->level], "$tsFormatted: " . $line->message));
         }
 
         return $logWindow;
     }
 
-    protected function prepareCurlInfoTable()
+    /**
+     * @return Hint|Table|string
+     */
+    protected function prepareCurlInfoTable(): Hint|Table|string
     {
         try {
             $table = new Table();
@@ -205,27 +219,34 @@ protected function prepareCurlInfoTable()
         */
     }
 
-    protected function prepareVsphereConnectionTable()
+    /**
+     * @return Hint|VsphereApiConnectionTable
+     */
+    protected function prepareVsphereConnectionTable(): Hint|VsphereApiConnectionTable
     {
         try {
-            $table = new VsphereApiConnectionTable(array_map(function ($row) {
-                return [
+            $table = new VsphereApiConnectionTable(array_map(
+                fn($row) => [
                     'vCenterId' => $row->vCenterId,
                     'server'    => $row->server,
-                    'state'     =>  $row->state . (isset($row->lastErrorMessage) ? ': ' . $row->lastErrorMessage : ''),
-                ];
-            }, $this->syncRpcCall('vsphere.getApiConnections')));
+                    'state'     => $row->state . (isset($row->lastErrorMessage) ? ': ' . $row->lastErrorMessage : '')
+                ],
+                $this->syncRpcCall('vsphere.getApiConnections')
+            ));
             if ($table->count() === 0) {
                 return Hint::info($this->translate('The vSphereDB Daemon is currently not polling any vCenter'));
             }
 
             return $table;
-        } catch (\Exception $exception) {
+        } catch (Exception $exception) {
             return Hint::error($exception->getMessage());
         }
     }
 
-    protected function handleTabs()
+    /**
+     * @return void
+     */
+    protected function handleTabs(): void
     {
         $action = $this->getRequest()->getControllerName();
         $tabs = $this->tabs(new MainTabs($this->Auth(), $this->db()));
diff --git a/application/controllers/DatacentersController.php b/application/controllers/DatacentersController.php
index 965216bc..e920ceec 100644
--- a/application/controllers/DatacentersController.php
+++ b/application/controllers/DatacentersController.php
@@ -10,7 +10,7 @@
 
 class DatacentersController extends ObjectsController
 {
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->addSingleTab($this->translate('Datacenters'));
         $table = new DatacentersTable($this->db(), $this->url());
diff --git a/application/controllers/DatastoreController.php b/application/controllers/DatastoreController.php
index 00fc3b9c..3b9a5f34 100644
--- a/application/controllers/DatastoreController.php
+++ b/application/controllers/DatastoreController.php
@@ -4,6 +4,8 @@
 
 use gipfl\IcingaWeb2\Link;
 use gipfl\Web\Table\NameValueTable;
+use Icinga\Exception\MissingParameterException;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
 use Icinga\Module\Vspheredb\DbObject\Datastore;
 use Icinga\Module\Vspheredb\PathLookup;
@@ -21,10 +23,10 @@ class DatastoreController extends Controller
     use SingleObjectMonitoring;
 
     /**
-     * @throws \Icinga\Exception\MissingParameterException
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws MissingParameterException
+     * @throws NotFoundError
      */
-    public function indexAction()
+    public function indexAction(): void
     {
         $ds = $this->addDatastore();
         $lookup = new PathLookup($this->db()->getDbAdapter());
@@ -56,7 +58,7 @@ public function indexAction()
                 $ds->get('capacity') - $ds->get('free_space')
             ),
             $this->translate('Uncommitted') => $this->bytes($ds->get('uncommitted')),
-            $this->translate('Sizing') => $this->sizingInfo($ds),
+            $this->translate('Sizing') => $this->sizingInfo($ds)
         ]);
         $vms = VmsOnDatastoreTable::create($ds);
 
@@ -64,10 +66,10 @@ public function indexAction()
     }
 
     /**
-     * @throws \Icinga\Exception\MissingParameterException
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws MissingParameterException
+     * @throws NotFoundError
      */
-    public function eventsAction()
+    public function eventsAction(): void
     {
         $ds = $this->addDatastore();
         $table = new EventHistoryTable($this->db());
@@ -75,17 +77,18 @@ public function eventsAction()
             ->renderTo($this);
     }
 
-    public function monitoringAction()
+    public function monitoringAction(): void
     {
         $this->showMonitoringDetails($this->addDatastore());
     }
 
     /**
      * @return Datastore
-     * @throws \Icinga\Exception\MissingParameterException
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @throws MissingParameterException
+     * @throws NotFoundError
      */
-    protected function addDatastore()
+    protected function addDatastore(): Datastore
     {
         $ds = Datastore::loadWithUuid($this->params->getRequired('uuid'), $this->db());
         $ds->object()->set('object_name', Anonymizer::anonymizeString($ds->object()->get('object_name')));
@@ -96,7 +99,10 @@ protected function addDatastore()
         return $ds;
     }
 
-    protected function handleTabs()
+    /**
+     * @return void
+     */
+    protected function handleTabs(): void
     {
         $params = ['uuid' => $this->params->get('uuid')];
         $this->tabs()->add('index', [
@@ -118,7 +124,12 @@ protected function sizingInfo(Datastore $ds)
     {
     }
 
-    protected function bytes($bytes)
+    /**
+     * @param $bytes
+     *
+     * @return string
+     */
+    protected function bytes($bytes): string
     {
         return Format::bytes($bytes, Format::STANDARD_IEC);
     }
diff --git a/application/controllers/DatastoresController.php b/application/controllers/DatastoresController.php
index eca3565e..bab388f2 100644
--- a/application/controllers/DatastoresController.php
+++ b/application/controllers/DatastoresController.php
@@ -11,7 +11,7 @@
 
 class DatastoresController extends ObjectsController
 {
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->handleTabs();
         $this->addTreeViewToggle();
@@ -35,7 +35,7 @@ public function indexAction()
         $this->content()->prepend($summaries);
     }
 
-    public function exportAction()
+    public function exportAction(): void
     {
         $this->sendExport('datastore');
     }
diff --git a/application/controllers/DetailSections.php b/application/controllers/DetailSections.php
index 1aead75f..aee8eadc 100644
--- a/application/controllers/DetailSections.php
+++ b/application/controllers/DetailSections.php
@@ -3,30 +3,44 @@
 namespace Icinga\Module\Vspheredb\Controllers;
 
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\Html\HtmlString;
 
 trait DetailSections
 {
-    protected function section($content)
+    /**
+     * @param mixed $content
+     *
+     * @return ?HtmlElement
+     */
+    protected function section(mixed $content): ?HtmlElement
     {
         $content = Html::wantHtml($content)->render();
-        if (\strlen($content) === 0) {
+        if (strlen($content) === 0) {
             return null;
         }
 
-        return Html::tag('div', [
-            'class' => 'section',
-        ], new HtmlString($content));
+        return Html::tag('div', ['class' => 'section'], new HtmlString($content));
     }
 
-    protected function addSection($content)
+    /**
+     * @param mixed $content
+     *
+     * @return $this
+     */
+    protected function addSection(mixed $content): static
     {
         $this->content()->add($this->section($content));
 
         return $this;
     }
 
-    protected function addSections(array $sections)
+    /**
+     * @param array $sections
+     *
+     * @return $this
+     */
+    protected function addSections(array $sections): static
     {
         foreach ($sections as $section) {
             $this->addSection($section);
diff --git a/application/controllers/EventsController.php b/application/controllers/EventsController.php
index e71a1929..4643327d 100644
--- a/application/controllers/EventsController.php
+++ b/application/controllers/EventsController.php
@@ -6,23 +6,23 @@
 use gipfl\IcingaWeb2\Url;
 use gipfl\Web\Widget\Hint;
 use Icinga\Date\DateFormatter;
+use Icinga\Module\Vspheredb\Web\Controller;
 use Icinga\Module\Vspheredb\Web\Form\FilterHostParentForm;
 use Icinga\Module\Vspheredb\Web\Table\EventHistoryTable;
-use Icinga\Module\Vspheredb\Web\Controller;
 use Icinga\Module\Vspheredb\Web\Widget\CalendarForEvents;
 use Icinga\Module\Vspheredb\Web\Widget\VMotionHeatmap;
 use Ramsey\Uuid\Uuid;
 
 class EventsController extends Controller
 {
-    public function init()
+    public function init(): void
     {
         $this->assertPermission('vspheredb/admin');
         parent::init();
         $this->handleTabs();
     }
 
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->actions()->add(Link::create(
             $this->translate('Calendar'),
@@ -30,7 +30,7 @@ public function indexAction()
             $this->url()->getParams()->toArray(false),
             [
                 'class' => 'icon-calendar',
-                'data-base-target' => '_main',
+                'data-base-target' => '_main'
             ]
         ));
 
@@ -62,7 +62,10 @@ public function indexAction()
         $table->renderTo($this);
     }
 
-    protected function addFilterForm()
+    /**
+     * @return FilterHostParentForm
+     */
+    protected function addFilterForm(): FilterHostParentForm
     {
         $form = new FilterHostParentForm($this->db());
         $form->handleRequest($this->getServerRequest());
@@ -71,7 +74,7 @@ protected function addFilterForm()
         return $form;
     }
 
-    public function heatmapAction()
+    public function heatmapAction(): void
     {
         $this->actions()->add(Link::create(
             $this->translate('Table'),
@@ -79,7 +82,7 @@ public function heatmapAction()
             $this->url()->getParams()->toArray(false),
             [
                 'class' => 'icon-th-list',
-                'data-base-target' => '_main',
+                'data-base-target' => '_main'
             ]
         ));
 
@@ -97,7 +100,10 @@ public function heatmapAction()
         $this->content()->add(new CalendarForEvents($heatMap, $baseUrl, $form->getColors()));
     }
 
-    protected function handleTabs()
+    /**
+     * @return void
+     */
+    protected function handleTabs(): void
     {
         $params = [];
         if ($day = $this->params->get('day')) {
@@ -108,7 +114,7 @@ protected function handleTabs()
         }
         $tabs = $this->tabs()->add('events', [
             'label' => $this->translate('Events'),
-            'url'   => $this->url(),
+            'url'   => $this->url()
         ])->add('alarms', [
             'label' => $this->translate('Alarms'),
             'url'   => $alarmsUrl,
diff --git a/application/controllers/HostController.php b/application/controllers/HostController.php
index 040ffb6d..f18c3a81 100644
--- a/application/controllers/HostController.php
+++ b/application/controllers/HostController.php
@@ -9,6 +9,7 @@
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Module\Vspheredb\Web\Controller;
+use Icinga\Module\Vspheredb\Web\Table\EventHistoryTable;
 use Icinga\Module\Vspheredb\Web\Table\HostHbaTable;
 use Icinga\Module\Vspheredb\Web\Table\HostPciDevicesTable;
 use Icinga\Module\Vspheredb\Web\Table\HostPhysicalNicTable;
@@ -17,29 +18,28 @@
 use Icinga\Module\Vspheredb\Web\Table\Object\HostSystemInfoTable;
 use Icinga\Module\Vspheredb\Web\Table\Object\HostVirtualizationInfoTable;
 use Icinga\Module\Vspheredb\Web\Table\Objects\VmsTable;
-use Icinga\Module\Vspheredb\Web\Table\EventHistoryTable;
 use Icinga\Module\Vspheredb\Web\Widget\AdditionalTableActions;
 use Icinga\Module\Vspheredb\Web\Widget\CustomValueDetails;
 use Icinga\Module\Vspheredb\Web\Widget\HostHeader;
 use Icinga\Module\Vspheredb\Web\Widget\HostMonitoringInfo;
 use Icinga\Module\Vspheredb\Web\Widget\Summaries;
 use Icinga\Module\Vspheredb\Web\Widget\TaggingDetails;
+use ipl\Html\Attributes;
 
 class HostController extends Controller
 {
     use DetailSections;
     use SingleObjectMonitoring;
 
-    /** @var HostHeader */
-    protected $hostHeader;
+    protected ?HostHeader $hostHeader = null;
 
     /**
      * @throws MissingParameterException|NotFoundError
      */
-    public function indexAction()
+    public function indexAction(): void
     {
         $host = $this->addHost();
-        $this->content()->addAttributes(['class' => 'host-info']);
+        $this->content()->addAttributes(Attributes::create(['class' => 'host-info']));
         $vCenter = VCenter::load($host->get('vcenter_uuid'), $host->getConnection());
         $quickStats = HostQuickStats::loadFor($host);
         $this->addSections([
@@ -50,15 +50,14 @@ public function indexAction()
             new HostHardwareInfoTable($host, $quickStats),
             new HostMonitoringInfo($host),
             new HostPhysicalNicTable($host),
-            new HostHbaTable($host),
+            new HostHbaTable($host)
         ]);
     }
 
     /**
      * @throws MissingParameterException|NotFoundError
-
      */
-    public function vmsAction()
+    public function vmsAction(): void
     {
         $host = $this->addHost();
         $table = new VmsTable($this->db(), $this->url());
@@ -72,9 +71,8 @@ public function vmsAction()
 
     /**
      * @throws MissingParameterException|NotFoundError
-
      */
-    public function sensorsAction()
+    public function sensorsAction(): void
     {
         $table = new HostSensorsTable($this->db());
         $table->filterHost($this->addHost());
@@ -83,9 +81,8 @@ public function sensorsAction()
 
     /**
      * @throws MissingParameterException|NotFoundError
-
      */
-    public function pcidevicesAction()
+    public function pcidevicesAction(): void
     {
         $table = new HostPciDevicesTable($this->db());
         $table->filterHost($this->addHost())->renderTo($this);
@@ -93,30 +90,30 @@ public function pcidevicesAction()
 
     /**
      * @throws MissingParameterException|NotFoundError
-
      */
-    public function eventsAction()
+    public function eventsAction(): void
     {
         $table = new EventHistoryTable($this->db());
         $table->filterHost($this->addHost())->renderTo($this);
     }
 
-    public function monitoringAction()
+    public function monitoringAction(): void
     {
         $this->showMonitoringDetails($this->addHost());
     }
 
     /**
      * @return HostSystem
+     *
      * @throws MissingParameterException|NotFoundError
      */
-    protected function addHost()
+    protected function addHost(): HostSystem
     {
         $host = HostSystem::loadWithUuid($this->params->getRequired('uuid'), $this->db());
         $this->getRestrictionHelper()->assertAccessToVCenterUuidIsGranted($host->get('vcenter_uuid'));
         $quickStats = HostQuickStats::loadFor($host);
         $this->controls()->add($this->hostHeader = new HostHeader($host, $quickStats));
-        $this->controls()->addAttributes(['class' => 'controls-with-object-header']);
+        $this->controls()->addAttributes(Attributes::create(['class' => 'controls-with-object-header']));
         $this->setTitle($host->object()->get('object_name'));
         $this->handleTabs($host);
 
@@ -125,9 +122,12 @@ protected function addHost()
 
     /**
      * @param HostSystem $host
+     *
+     * @return void
+     *
      * @throws MissingParameterException
      */
-    protected function handleTabs(HostSystem $host)
+    protected function handleTabs(HostSystem $host): void
     {
         $hexId = $this->params->getRequired('uuid');
         $this->tabs()->add('index', [
diff --git a/application/controllers/HostsController.php b/application/controllers/HostsController.php
index 050d531a..69ce3618 100644
--- a/application/controllers/HostsController.php
+++ b/application/controllers/HostsController.php
@@ -3,15 +3,15 @@
 namespace Icinga\Module\Vspheredb\Controllers;
 
 use Icinga\Authentication\Auth;
-use Icinga\Module\Vspheredb\Web\OverviewTree;
-use Icinga\Module\Vspheredb\Web\Widget\AdditionalTableActions;
 use Icinga\Module\Vspheredb\Web\Controller\ObjectsController;
+use Icinga\Module\Vspheredb\Web\OverviewTree;
 use Icinga\Module\Vspheredb\Web\Table\Objects\HostsTable;
+use Icinga\Module\Vspheredb\Web\Widget\AdditionalTableActions;
 use Icinga\Module\Vspheredb\Web\Widget\Summaries;
 
 class HostsController extends ObjectsController
 {
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->handleTabs();
         $this->addTreeViewToggle();
@@ -40,7 +40,7 @@ public function indexAction()
         $this->content()->prepend($summaries);
     }
 
-    public function exportAction()
+    public function exportAction(): void
     {
         $this->sendExport('host_system');
     }
diff --git a/application/controllers/MonitoringController.php b/application/controllers/MonitoringController.php
index 21b3b9fd..a56ac0dc 100644
--- a/application/controllers/MonitoringController.php
+++ b/application/controllers/MonitoringController.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Controllers;
 
+use Exception;
 use gipfl\IcingaWeb2\Link;
 use gipfl\Web\Widget\Hint;
 use Icinga\Module\Vspheredb\DbObject\ManagedObject;
@@ -21,21 +22,22 @@
 use Icinga\Module\Vspheredb\Web\Table\TableWithVCenterFilter;
 use Icinga\Module\Vspheredb\Web\Widget\Documentation;
 use Icinga\Web\Notification;
+use ipl\Html\Attributes;
+use ipl\Html\Contract\Form;
 use ipl\Html\Html;
 use Ramsey\Uuid\Uuid;
-use RuntimeException;
 
 class MonitoringController extends Controller
 {
     use AsyncControllerHelper;
 
-    protected $vCenterFilterForm;
+    protected ?FilterVCenterForm $vCenterFilterForm = null;
 
-    public function init()
+    public function init(): void
     {
         parent::init();
         $action = $this->getRequest()->getActionName();
-        if (preg_match('/tree$/', $action) || in_array($action, ['index', 'configuration', 'history'])) {
+        if (str_ends_with($action, 'tree') || in_array($action, ['index', 'configuration', 'history'])) {
             $tabs = $this->tabs();
             $tabs->add('index', [
                 'label' => $this->translate('Monitoring'),
@@ -61,7 +63,7 @@ public function init()
             }
             $tabs->activate($action);
         }
-        if (preg_match('/tree$/', $action)) {
+        if (str_ends_with($action, 'tree')) {
             $this->actions()->add(
                 Link::create($this->translate('Back to overview'), 'vspheredb/monitoring', null, [
                     'class' => 'icon-left-small'
@@ -74,7 +76,7 @@ public function init()
         }
     }
 
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->addTitle($this->translate('Monitoring Rules'));
         $this->setAutorefreshInterval(20);
@@ -83,7 +85,7 @@ public function indexAction()
         $table->renderTo($this);
     }
 
-    public function problemsAction()
+    public function problemsAction(): void
     {
         $this->addSingleTab($this->translate('Current Problems'));
         $vCenter = $this->requireVCenter();
@@ -97,7 +99,7 @@ public function problemsAction()
         $table->renderTo($this);
     }
 
-    public function historyAction()
+    public function historyAction(): void
     {
         $this->addTitle($this->translate('Monitoring Rules - Problem History'));
         $this->setAutorefreshInterval(20);
@@ -106,13 +108,11 @@ public function historyAction()
         $table->renderTo($this);
     }
 
-    public function configurationAction()
+    public function configurationAction(): void
     {
         $this->assertPermission('vspheredb/admin');
         $this->addTitle($this->translate('Monitoring Rules'));
-        $this->content()->addAttributes([
-            'class' => 'overview-chapter'
-        ]);
+        $this->content()->addAttributes(Attributes::create(['class' => 'overview-chapter']));
         $this->content()->add([
             Hint::info(Html::sprintf($this->translate(
                 'The Icinga vSphere%s Integration ships a lot of data, state and sensor values.'
@@ -143,45 +143,55 @@ public function configurationAction()
         ]);
     }
 
-    public function hostrulesAction()
+    public function hostrulesAction(): void
     {
         $this->showType(ObjectType::HOST_SYSTEM);
     }
 
-    public function hosttreeAction()
+    public function hosttreeAction(): void
     {
         $this->showTree(ObjectType::HOST_SYSTEM);
     }
 
-    public function vmrulesAction()
+    public function vmrulesAction(): void
     {
         $this->showType(ObjectType::VIRTUAL_MACHINE);
     }
 
-    public function vmtreeAction()
+    public function vmtreeAction(): void
     {
         $this->showTree(ObjectType::VIRTUAL_MACHINE);
     }
 
-    public function datastorerulesAction()
+    public function datastorerulesAction(): void
     {
         $this->showType(ObjectType::DATASTORE);
     }
 
-    public function datastoretreeAction()
+    public function datastoretreeAction(): void
     {
         $this->showTree(ObjectType::DATASTORE);
     }
 
-    public function showTree($chosenType)
+    /**
+     * @param ObjectType $chosenType
+     *
+     * @return void
+     */
+    public function showTree(ObjectType $chosenType): void
     {
         $this->assertPermission('vspheredb/admin');
         $this->addTitle($this->translate('Monitoring'));
-        $tree = new MonitoringRulesTree($this->db(), $chosenType);
-        $this->content()->add(new MonitoringRulesTreeRenderer($tree, "vspheredb/monitoring/{$chosenType}rules"));
+        $tree = new MonitoringRulesTree($this->db(), $chosenType->value);
+        $this->content()->add(new MonitoringRulesTreeRenderer($tree, "vspheredb/monitoring/{$chosenType->value}rules"));
     }
 
-    public function showType($chosenType)
+    /**
+     * @param ObjectType $chosenType
+     *
+     * @return void
+     */
+    public function showType(ObjectType $chosenType): void
     {
         $this->assertPermission('vspheredb/admin');
         $this->addSingleTab($this->translate('Rules'));
@@ -222,12 +232,12 @@ public function showType($chosenType)
             }
         }
         $this->addTitle($title);
-        $tree = new MonitoringRulesTree($db, $chosenType);
-        $storedConfig = MonitoringRuleSet::loadOptionalForUuid($binaryUuid, $chosenType, $db);
+        $tree = new MonitoringRulesTree($db, $chosenType->value);
+        $storedConfig = MonitoringRuleSet::loadOptionalForUuid($binaryUuid, $chosenType->value, $db);
         $inherited = InheritedSettings::loadFor($binaryUuid, $tree, $db);
         $inherited->setInternalDefaults(RuleSetRegistry::default());
         $form = new RuleForm($chosenType, $binaryUuid, $db, $inherited, $storedConfig);
-        $form->on(RuleForm::ON_SUCCESS, function (RuleForm $form) use ($title) {
+        $form->on(Form::ON_SUBMIT, function (RuleForm $form) use ($title) {
             if ($form->hasNotBeenModified()) {
                 Notification::info($this->translate('No change has been applied'));
                 $this->redirectNow($this->url());
@@ -241,7 +251,7 @@ public function showType($chosenType)
                         'Current problems have NOT been recalculated, they will be applied with a short delay'
                     ));
                 }
-            } catch (\Exception $e) {
+            } catch (Exception $e) {
                 Notification::info(
                     $this->translate(
                         'Error when triggering problem recalculation, changes will be applied with a short delay'
@@ -267,22 +277,28 @@ public function showType($chosenType)
         ]);
     }
 
-    protected function getTypeLabelForObjectType(string $type): string
+    /**
+     * @param ObjectType $type
+     *
+     * @return string
+     */
+    protected function getTypeLabelForObjectType(ObjectType $type): string
     {
-        switch ($type) {
-            case 'host':
-                return $this->translate('Host Systems');
-            case 'vm':
-                return $this->translate('Virtual Machines');
-            case 'datastore':
-                return $this->translate('Datastores');
-        }
-
-        throw new RuntimeException("Unexpected object type: '$type'");
+        return match ($type) {
+            ObjectType::HOST_SYSTEM     => $this->translate('Host Systems'),
+            ObjectType::VIRTUAL_MACHINE => $this->translate('Virtual Machines'),
+            ObjectType::DATASTORE       => $this->translate('Datastores')
+        };
     }
 
-    // Duplicated from ObjectsController
-    protected function filterByVCenterIfRequired(TableWithVCenterFilter $table)
+    /**
+     * Duplicated from ObjectsController
+     *
+     * @param TableWithVCenterFilter $table
+     *
+     * @return void
+     */
+    protected function filterByVCenterIfRequired(TableWithVCenterFilter $table): void
     {
         $this->getRestrictionHelper()->restrictTable($table);
         $this->controls()->prepend($this->getVCenterFilterForm());
@@ -292,7 +308,11 @@ protected function filterByVCenterIfRequired(TableWithVCenterFilter $table)
         }
     }
 
-    // Duplicated from ObjectsController
+    /**
+     * Duplicated from ObjectsController
+     *
+     * @return FilterVCenterForm
+     */
     protected function getVCenterFilterForm(): FilterVCenterForm
     {
         if ($this->vCenterFilterForm === null) {
diff --git a/application/controllers/OverviewController.php b/application/controllers/OverviewController.php
index 3e883ee3..c43c2ae8 100644
--- a/application/controllers/OverviewController.php
+++ b/application/controllers/OverviewController.php
@@ -7,7 +7,7 @@
 
 class OverviewController extends ObjectsController
 {
-    public function indexAction()
+    public function indexAction(): void
     {
         $type = $this->params->getRequired('type');
         $this->activateTab($type)
@@ -15,7 +15,12 @@ public function indexAction()
              ->content()->add(new OverviewTree($this->db(), $this->getRestrictionHelper(), $type));
     }
 
-    protected function activateTab($name)
+    /**
+     * @param string $name
+     *
+     * @return $this
+     */
+    protected function activateTab(string $name): static
     {
         $this->controls()->getTabs()->add('datastore', [
             'label' => $this->translate('Datastores'),
diff --git a/application/controllers/PerfdataController.php b/application/controllers/PerfdataController.php
index 8fe28a3f..b29d58f9 100644
--- a/application/controllers/PerfdataController.php
+++ b/application/controllers/PerfdataController.php
@@ -17,19 +17,19 @@
 use Icinga\Module\Vspheredb\Web\Tabs\VCenterTabs;
 use Icinga\Module\Vspheredb\Web\Widget\AdditionalTableActions;
 use Icinga\Web\Notification;
-use ipl\Html\Html;
+use ipl\Html\Contract\Form;
 use Ramsey\Uuid\Uuid;
 
 class PerfdataController extends Controller
 {
     use AsyncControllerHelper;
 
-    public function init()
+    public function init(): void
     {
         $this->assertPermission('vspheredb/admin');
     }
 
-    public function countersAction()
+    public function countersAction(): void
     {
         $vCenter = $this->requireVCenter();
         $this->tabs(new VCenterTabs($vCenter))->activate('perfcounters');
@@ -47,14 +47,14 @@ public function countersAction()
         $table->renderTo($this);
     }
 
-    public function consumersAction()
+    public function consumersAction(): void
     {
         $this->setAutorefreshInterval(10);
         $this->tabs(new ConfigTabs())->activate('perfdata');
         $this->addTitle($this->translate('Performance Data Consumers'));
         $this->actions()->add(Link::create($this->translate('Add'), 'vspheredb/perfdata/consumer', null, [
             'data-base-target' => '_next',
-            'class'            => 'icon-plus',
+            'class'            => 'icon-plus'
         ]));
         $table = new PerfDataConsumerTable($this->db()->getDbAdapter());
         if (count($table) === 0) {
@@ -64,20 +64,20 @@ public function consumersAction()
         $table->renderTo($this);
     }
 
-    public function consumerAction()
+    public function consumerAction(): void
     {
         $store = new ZfDbStore($this->db()->getDbAdapter());
         $form = new PerfdataConsumerForm($this->loop(), $this->remoteClient(), $store);
-        $form->on($form::ON_DELETE, function () {
+        $form->on(PerfdataConsumerForm::ON_DELETE, function () {
             Notification::success($this->translate('Performance Data Consumer has been removed'));
             $this->redirectNow('vspheredb/perfdata/consumers');
         });
-        $form->on(PerfdataConsumerForm::ON_SUCCESS, function (PerfdataConsumerForm $form) {
-            if ($form->wasNew()) {
-                Notification::success($this->translate('Performance Data Consumer has been created'));
-            } else {
-                Notification::success($this->translate('Performance Data Consumer has been updated'));
-            }
+        $form->on(Form::ON_SUBMIT, function (PerfdataConsumerForm $form) {
+            Notification::success(
+                $form->wasNew()
+                    ? $this->translate('Performance Data Consumer has been created')
+                    : $this->translate('Performance Data Consumer has been updated')
+            );
             $this->redirectNow(Url::fromPath('vspheredb/perfdata/consumer', [
                 'uuid' => Uuid::fromBytes($form->getObject()->get('uuid'))->toString()
             ]));
diff --git a/application/controllers/PhperrorController.php b/application/controllers/PhperrorController.php
deleted file mode 100644
index be00199e..00000000
--- a/application/controllers/PhperrorController.php
+++ /dev/null
@@ -1,43 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Controllers;
-
-use Icinga\Application\Icinga;
-use Icinga\Module\Vspheredb\Application\DependencyChecker;
-use Icinga\Module\Vspheredb\Web\Table\Dependency\DependencyInfoTable;
-use Icinga\Web\Controller;
-
-class PhperrorController extends Controller
-{
-    public function errorAction()
-    {
-        $this->getTabs()->add('error', [
-            'label' => $this->translate('Error'),
-            'url'   => $this->getRequest()->getUrl()
-        ])->activate('error');
-        $requiredVersion = '7.1.x';
-        $msg = $this->translate(
-            "PHP version %s is required for vSphereDB, you're running %s."
-        );
-        $this->view->title = $this->translate('Unsatisfied dependencies');
-        $this->view->message = sprintf($msg, $requiredVersion, PHP_VERSION);
-    }
-
-    public function dependenciesAction()
-    {
-        $checker = new DependencyChecker(Icinga::app());
-        if ($checker->satisfiesDependencies($this->Module())) {
-            $this->redirectNow('vspheredb/vcenters');
-        }
-        $this->setAutorefreshInterval(15);
-        $this->getTabs()->add('error', [
-            'label' => $this->translate('Error'),
-            'url'   => $this->getRequest()->getUrl()
-        ])->activate('error');
-        $this->view->title = $this->translate('Unsatisfied dependencies');
-        $this->view->table = (new DependencyInfoTable($checker, $this->Module()))->render();
-        $this->view->message = $this->translate(
-            "Icinga vSphereDb depends on the following modules, please install/upgrade as required"
-        );
-    }
-}
diff --git a/application/controllers/PortgroupController.php b/application/controllers/PortgroupController.php
index 67595816..d5e3c805 100644
--- a/application/controllers/PortgroupController.php
+++ b/application/controllers/PortgroupController.php
@@ -3,6 +3,8 @@
 namespace Icinga\Module\Vspheredb\Controllers;
 
 use Icinga\Authentication\Auth;
+use Icinga\Exception\MissingParameterException;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\DbObject\DistributedVirtualPortgroup;
 use Icinga\Module\Vspheredb\Web\Controller\ObjectsController;
 use Icinga\Module\Vspheredb\Web\Table\Objects\NetworkAdaptersTable;
@@ -12,10 +14,10 @@
 class PortgroupController extends ObjectsController
 {
     /**
-     * @throws \Icinga\Exception\MissingParameterException
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws MissingParameterException
+     * @throws NotFoundError
      */
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->setAutorefreshInterval(15);
         $table = new NetworkAdaptersTable($this->db(), $this->url());
diff --git a/application/controllers/ResourcepoolsController.php b/application/controllers/ResourcepoolsController.php
index 08e1fb1f..1f1a8876 100644
--- a/application/controllers/ResourcepoolsController.php
+++ b/application/controllers/ResourcepoolsController.php
@@ -10,7 +10,7 @@
 
 class ResourcepoolsController extends ObjectsController
 {
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->addSingleTab($this->translate('Resource Pools'));
         $table = new ResourcePoolsTable($this->db(), $this->url());
diff --git a/application/controllers/ResourcesController.php b/application/controllers/ResourcesController.php
index d6b6e115..983e2fc8 100644
--- a/application/controllers/ResourcesController.php
+++ b/application/controllers/ResourcesController.php
@@ -4,6 +4,7 @@
 
 use gipfl\IcingaWeb2\Link;
 use Icinga\Authentication\Auth;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Module\Vspheredb\Web\Controller\ObjectsController;
 use Icinga\Module\Vspheredb\Web\Table\Objects\ComputeClusterHostSummaryTable;
@@ -15,9 +16,9 @@
 class ResourcesController extends ObjectsController
 {
     /**
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws NotFoundError
      */
-    public function clustersAction()
+    public function clustersAction(): void
     {
         if ($vCenterUuid = $this->params->get('vcenter')) {
             $vCenter = VCenter::loadWithUuid($vCenterUuid, $this->db());
@@ -47,9 +48,9 @@ public function clustersAction()
     }
 
     /**
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws NotFoundError
      */
-    public function hostsAction()
+    public function hostsAction(): void
     {
         $this->addSingleTab('Compute Resources');
 
@@ -73,7 +74,7 @@ public function hostsAction()
         $this->showTable($table, 'vspheredb/groupedvms');
     }
 
-    public function projectsAction()
+    public function projectsAction(): void
     {
         $this->addSingleTab('Project Summary');
         $this->setAutorefreshInterval(15);
diff --git a/application/controllers/RpcServerUpdateHelper.php b/application/controllers/RpcServerUpdateHelper.php
index 6afec32a..cb995783 100644
--- a/application/controllers/RpcServerUpdateHelper.php
+++ b/application/controllers/RpcServerUpdateHelper.php
@@ -2,26 +2,28 @@
 
 namespace Icinga\Module\Vspheredb\Controllers;
 
+use Exception;
 use Icinga\Module\Vspheredb\DbObject\VCenterServer;
 use Icinga\Module\Vspheredb\Polling\ServerSet;
 
 trait RpcServerUpdateHelper
 {
-    protected function sendServerInfoToSocket()
+    protected function sendServerInfoToSocket(): string
     {
         /** @var ConfigurationController $this */
         try {
             $connection = $this->db();
             if (
-                $this->syncRpcCall('vsphere.setServers', [
-                'servers' => ServerSet::fromServers(VCenterServer::loadEnabledServers($connection))
-                ])
+                $this->syncRpcCall(
+                    'vsphere.setServers',
+                    ['servers' => ServerSet::fromServers(VCenterServer::loadEnabledServers($connection))]
+                )
             ) {
                 return $this->translate('Daemon configuration has been refreshed');
-            } else {
-                return $this->translate('Daemon configuration has NOT been refreshed');
             }
-        } catch (\Exception $e) {
+
+            return $this->translate('Daemon configuration has NOT been refreshed');
+        } catch (Exception $e) {
             return $this->translate('Daemon configuration refresh FAILED: ' . $e->getMessage());
         }
     }
diff --git a/application/controllers/SingleObjectMonitoring.php b/application/controllers/SingleObjectMonitoring.php
index 75a75f0d..193861cc 100644
--- a/application/controllers/SingleObjectMonitoring.php
+++ b/application/controllers/SingleObjectMonitoring.php
@@ -6,6 +6,7 @@
 use gipfl\Web\Widget\Hint;
 use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
 use Icinga\Module\Vspheredb\Monitoring\CheckRunner;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
 use Icinga\Module\Vspheredb\Web\Table\Monitoring\MonitoringRuleProblemHistoryTable;
 use Icinga\Module\Vspheredb\Web\Widget\CheckPluginHelper;
 use ipl\Html\Html;
@@ -13,7 +14,12 @@
 
 trait SingleObjectMonitoring
 {
-    protected function showMonitoringDetails(BaseDbObject $object)
+    /**
+     * @param BaseDbObject $object
+     *
+     * @return void
+     */
+    protected function showMonitoringDetails(BaseDbObject $object): void
     {
         $history = $this->params->get('history');
         if ($history) {
@@ -37,7 +43,12 @@ protected function showMonitoringDetails(BaseDbObject $object)
         }
     }
 
-    protected function showMonitoringHistory(BaseDbObject $object)
+    /**
+     * @param BaseDbObject $object
+     *
+     * @return void
+     */
+    protected function showMonitoringHistory(BaseDbObject $object): void
     {
         $this->setAutorefreshInterval(20);
         $table = new MonitoringRuleProblemHistoryTable($this->db()->getDbAdapter());
@@ -46,21 +57,20 @@ protected function showMonitoringHistory(BaseDbObject $object)
         $table->renderTo($this);
     }
 
-    protected function showRuleConfigurationHint(BaseDbObject $object)
+    /**
+     * @param BaseDbObject $object
+     *
+     * @return void
+     */
+    protected function showRuleConfigurationHint(BaseDbObject $object): void
     {
-        switch ($object->getTableName()) {
-            case 'virtual_machine':
-                $tab = 'vmtree';
-                break;
-            case 'host_system':
-                $tab = 'hosttree';
-                break;
-            case 'datastore':
-                $tab = 'datastoretree';
-                break;
-            default:
-                $tab = null;
-        }
+        $tab = match ($object->getTableName()) {
+            'virtual_machine' => 'vmtree',
+            'host_system'     => 'hosttree',
+            'datastore'       => 'datastoretree',
+            default           => null,
+        };
+
         if ($tab) {
             $this->content()->add(Html::tag('p', [Html::tag('br'), Html::sprintf(
                 $this->translate('Please click %s to configure related Monitoring Rules'),
@@ -69,6 +79,12 @@ protected function showRuleConfigurationHint(BaseDbObject $object)
         }
     }
 
+    /**
+     * @param BaseDbObject $object
+     * @param ?bool $inspect
+     *
+     * @return Hint
+     */
     protected function createMonitoringHint(BaseDbObject $object, ?bool $inspect = null): Hint
     {
         return Hint::info(Html::sprintf(
@@ -81,13 +97,18 @@ protected function createMonitoringHint(BaseDbObject $object, ?bool $inspect = n
                 'class' => 'logOutput'
             ], sprintf(
                 'icingacli vspheredb check %s --uuid %s%s',
-                CheckRunner::getCheckTypeForObject($object),
+                ObjectType::fromDbObject($object)->value,
                 Uuid::fromBytes($object->get('uuid'))->toString(),
                 $inspect ? ' --inspect' : ''
             ))
         ));
     }
 
+    /**
+     * @param ?bool $inspect
+     *
+     * @return Link
+     */
     protected function createMonitoringInspectionLink(?bool $inspect = null): Link
     {
         if ($inspect) {
@@ -97,16 +118,21 @@ protected function createMonitoringInspectionLink(?bool $inspect = null): Link
                 null,
                 ['class' => 'icon-left-big']
             );
-        } else {
-            return Link::create(
-                $this->translate('Inspect'),
-                $this->url()->with('inspect', true),
-                null,
-                ['class' => 'icon-services']
-            );
         }
+
+        return Link::create(
+            $this->translate('Inspect'),
+            $this->url()->with('inspect', true),
+            null,
+            ['class' => 'icon-services']
+        );
     }
 
+    /**
+     * @param ?bool $inspect
+     *
+     * @return Link
+     */
     protected function createMonitoringHistoryLink(?bool $inspect = null): Link
     {
         if ($inspect) {
@@ -116,13 +142,13 @@ protected function createMonitoringHistoryLink(?bool $inspect = null): Link
                 null,
                 ['class' => 'icon-left-big']
             );
-        } else {
-            return Link::create(
-                $this->translate('Show history'),
-                $this->url()->with('history', true),
-                null,
-                ['class' => 'icon-history']
-            );
         }
+
+        return Link::create(
+            $this->translate('Show history'),
+            $this->url()->with('history', true),
+            null,
+            ['class' => 'icon-history']
+        );
     }
 }
diff --git a/application/controllers/StoragepodsController.php b/application/controllers/StoragepodsController.php
index a09ccfcf..7cf003fa 100644
--- a/application/controllers/StoragepodsController.php
+++ b/application/controllers/StoragepodsController.php
@@ -10,7 +10,7 @@
 
 class StoragepodsController extends ObjectsController
 {
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->addSingleTab($this->translate('Storage Pods'));
         $this->setAutorefreshInterval(15);
diff --git a/application/controllers/SwitchController.php b/application/controllers/SwitchController.php
index 50693960..65d8df70 100644
--- a/application/controllers/SwitchController.php
+++ b/application/controllers/SwitchController.php
@@ -3,6 +3,8 @@
 namespace Icinga\Module\Vspheredb\Controllers;
 
 use Icinga\Authentication\Auth;
+use Icinga\Exception\MissingParameterException;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\DbObject\DistributedVirtualSwitch;
 use Icinga\Module\Vspheredb\Web\Controller\ObjectsController;
 use Icinga\Module\Vspheredb\Web\Table\Objects\PortGroupsTable;
@@ -12,10 +14,10 @@
 class SwitchController extends ObjectsController
 {
     /**
-     * @throws \Icinga\Exception\MissingParameterException
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws MissingParameterException
+     * @throws NotFoundError
      */
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->setAutorefreshInterval(15);
         $table = new PortGroupsTable($this->db(), $this->url());
diff --git a/application/controllers/SwitchesController.php b/application/controllers/SwitchesController.php
index 2d26146b..dc7fa042 100644
--- a/application/controllers/SwitchesController.php
+++ b/application/controllers/SwitchesController.php
@@ -10,7 +10,7 @@
 
 class SwitchesController extends ObjectsController
 {
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->addSingleTab($this->translate('Switches'));
         $this->setAutorefreshInterval(15);
diff --git a/application/controllers/TopController.php b/application/controllers/TopController.php
index 0058d8f9..adb250f0 100644
--- a/application/controllers/TopController.php
+++ b/application/controllers/TopController.php
@@ -4,15 +4,16 @@
 
 use Icinga\Module\Vspheredb\Web\Controller;
 use Icinga\Module\Vspheredb\Web\Table\TopPerfTable;
+use Zend_Db_Select;
 
 class TopController extends Controller
 {
-    public function init()
+    public function init(): void
     {
         $this->assertPermission('vspheredb/admin');
     }
 
-    public function vmsAction()
+    public function vmsAction(): void
     {
         $this->setAutorefreshInterval(10);
         $parentId = $this->params->get('parent_uuid');
@@ -46,11 +47,11 @@ public function vmsAction()
                 $this->fetchTop(543, $parentId),
                 'formatMicroSeconds',
                 'createVmLink'
-            ),
+            )
         ]);
     }
 
-    public function foldersAction()
+    public function foldersAction(): void
     {
         $this->makeTabs();
         $this->content()->add([
@@ -89,11 +90,17 @@ public function foldersAction()
                 $this->fetchTopPerParent(543, 'AVG'),
                 'formatMicroSeconds',
                 'createTopForParentLink'
-            ),
+            )
         ]);
     }
 
-    protected function fetchTop($counterUuid, $parentUuid = null)
+    /**
+     * @param int $counterUuid
+     * @param     $parentUuid
+     *
+     * @return ?array
+     */
+    protected function fetchTop(int $counterUuid, $parentUuid = null): ?array
     {
         $query = $this->fetchTopQuery($counterUuid);
         if ($parentUuid !== null) {
@@ -102,7 +109,13 @@ protected function fetchTop($counterUuid, $parentUuid = null)
         return $this->db()->getDbAdapter()->fetchAll($query);
     }
 
-    protected function fetchTopPerParent($counterUuid, $agg)
+    /**
+     * @param int $counterUuid
+     * @param string $agg
+     *
+     * @return ?array
+     */
+    protected function fetchTopPerParent(int $counterUuid, string $agg): ?array
     {
         $db = $this->db()->getDbAdapter();
         $query = $db->select()->from(
@@ -112,23 +125,23 @@ protected function fetchTopPerParent($counterUuid, $agg)
                 'value_minus1' => "$agg(c.value_minus1)",
                 'value_minus2' => "$agg(c.value_minus2)",
                 'value_minus3' => "$agg(c.value_minus3)",
-                'value_minus4' => "$agg(c.value_minus4)",
+                'value_minus4' => "$agg(c.value_minus4)"
             ]
         )->join(
             ['o' => 'object'],
             'o.uuid = c.object_uuid',
             [
                 'o.uuid',
-                'o.overall_status',
+                'o.overall_status'
             ]
         )->join(
             ['p' => 'object'],
             'o.parent_uuid = p.uuid',
             [
                 'object_uuid' => 'p.uuid',
-                'object_name' => 'p.object_name',
+                'object_name' => 'p.object_name'
             ]
-        )->where('counter_key = ?', (int) $counterUuid)
+        )->where('counter_key = ?', $counterUuid)
             ->group('p.uuid')
             ->order('value_last DESC')
             ->limit($this->params->get('limit', 10));
@@ -136,7 +149,12 @@ protected function fetchTopPerParent($counterUuid, $agg)
         return $db->fetchAll($query);
     }
 
-    protected function fetchTopQuery($counterId)
+    /**
+     * @param int $counterId
+     *
+     * @return Zend_Db_Select
+     */
+    protected function fetchTopQuery(int $counterId): Zend_Db_Select
     {
         return $this->db()->getDbAdapter()->select()->from(
             ['c' => 'counter_300x5'],
@@ -148,7 +166,7 @@ protected function fetchTopQuery($counterId)
                 'c.value_minus1',
                 'c.value_minus2',
                 'c.value_minus3',
-                'c.value_minus4',
+                'c.value_minus4'
             ]
         )->join(
             ['o' => 'object'],
@@ -156,19 +174,30 @@ protected function fetchTopQuery($counterId)
             [
                 'o.uuid',
                 'object_name' => 'o.object_name',
-                'o.overall_status',
+                'o.overall_status'
             ]
-        )->where('counter_key = ?', (int) $counterId)
+        )->where('counter_key = ?', $counterId)
             ->order('value_last DESC')
             ->limit($this->params->get('limit', 10));
     }
 
-    protected function makeTopTable($title, $rows, $format, $link)
+    /**
+     * @param string $title
+     * @param ?array $rows
+     * @param ?string $format
+     * @param string $link
+     *
+     * @return TopPerfTable
+     */
+    protected function makeTopTable(string $title, ?array $rows, ?string $format, string $link): TopPerfTable
     {
         return new TopPerfTable($title, $rows, $format, $link);
     }
 
-    protected function makeTabs()
+    /**
+     * @return void
+     */
+    protected function makeTabs(): void
     {
         $this->tabs()->add('vms', [
             'label' => 'Top VMs',
diff --git a/application/controllers/VcenterController.php b/application/controllers/VcenterController.php
index 1241dbc0..1c4e53d6 100644
--- a/application/controllers/VcenterController.php
+++ b/application/controllers/VcenterController.php
@@ -20,7 +20,9 @@
 use Icinga\Module\Vspheredb\Web\Widget\UsageSummary;
 use Icinga\Module\Vspheredb\Web\Widget\VCenterHeader;
 use Icinga\Module\Vspheredb\Web\Widget\VCenterSummaries;
+use Icinga\Security\SecurityException;
 use Icinga\Web\Notification;
+use ipl\Html\Contract\Form;
 use Ramsey\Uuid\Uuid;
 
 class VcenterController extends Controller
@@ -28,7 +30,7 @@ class VcenterController extends Controller
     use AsyncControllerHelper;
     use RpcServerUpdateHelper;
 
-    public function indexAction()
+    public function indexAction(): void
     {
         $vCenter = $this->requireVCenter();
         $this->tabs(new VCenterTabs($vCenter))->activate('vcenter');
@@ -53,7 +55,7 @@ public function indexAction()
         $this->content()->add(new VCenterSummaries($vCenter));
     }
 
-    public function editAction()
+    public function editAction(): void
     {
         $this->assertPermission('vspheredb/admin');
         $vCenter = $this->requireVCenter();
@@ -75,7 +77,7 @@ public function editAction()
         };
 
         $form = new VCenterForm($vCenter);
-        $form->on(VCenterForm::ON_SUCCESS, $success);
+        $form->on(Form::ON_SUBMIT, $success);
         $form->handleRequest($this->getServerRequest());
         $this->content()->add($form);
 
@@ -84,7 +86,7 @@ public function editAction()
         if ($subscription = PerfdataSubscription::optionallyLoadForVCenter($vCenter, $store)) {
             $form->setObject($subscription);
         }
-        $form->on(VCenterShipMetricsForm::ON_SUCCESS, function () {
+        $form->on(Form::ON_SUBMIT, function () {
             $this->redirectNow($this->getOriginalUrl());
         });
         $form->on(VCenterShipMetricsForm::ON_DELETE, function () {
@@ -94,7 +96,7 @@ public function editAction()
         $this->content()->add($form);
 
         $form = new DeleteVCenterForm($this->db(), $vCenter, $this->remoteClient(), $this->loop());
-        $form->on(DeleteVCenterForm::ON_SUCCESS, function () use ($vCenter) {
+        $form->on(Form::ON_SUBMIT, function () use ($vCenter) {
             $this->redirectNow('vspheredb/vcenters');
         });
         $form->handleRequest($this->getServerRequest());
@@ -102,9 +104,9 @@ public function editAction()
     }
 
     /**
-     * @throws \Icinga\Security\SecurityException
+     * @throws SecurityException
      */
-    public function serverAction()
+    public function serverAction(): void
     {
         $this->assertPermission('vspheredb/admin');
         $this->addSingleTab($this->translate('vCenter Server'));
@@ -116,14 +118,12 @@ public function serverAction()
             $this->addTitle($this->translate('Create a new vCenter/ESXi-Connection'));
         }
 
-        $form->on(VCenterServerForm::ON_SUCCESS, function (VCenterServerForm $form) {
+        $form->on(Form::ON_SUBMIT, function (VCenterServerForm $form) {
             $object = $form->getObject();
             if ($object->hasBeenModified()) {
-                $msg = sprintf(
-                    $object->hasBeenLoadedFromDb()
-                        ? $this->translate('The Connection has successfully been stored')
-                        : $this->translate('A new Connection has successfully been created')
-                );
+                $msg = $object->hasBeenLoadedFromDb()
+                    ? $this->translate('The Connection has successfully been stored')
+                    : $this->translate('A new Connection has successfully been created');
                 $object->store();
                 $msg .= '. ' . $this->sendServerInfoToSocket();
             } else {
@@ -140,7 +140,10 @@ public function serverAction()
         }
     }
 
-    protected function handleTabs()
+    /**
+     * @return void
+     */
+    protected function handleTabs(): void
     {
         $action = $this->getRequest()->getActionName();
         $tabs = $this->tabs(new MainTabs($this->Auth(), $this->db()));
diff --git a/application/controllers/VcentersController.php b/application/controllers/VcentersController.php
index 560b83e7..ad55dc97 100644
--- a/application/controllers/VcentersController.php
+++ b/application/controllers/VcentersController.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Controllers;
 
+use Exception;
 use gipfl\IcingaWeb2\Link;
 use gipfl\Web\Widget\Hint;
 use Icinga\Authentication\Auth;
@@ -16,16 +17,20 @@
 use Icinga\Module\Vspheredb\Web\Widget\UsageSummary;
 use Icinga\Module\Vspheredb\WebUtil;
 use ipl\Html\Html;
+use Zend_Db_Select_Exception;
 
 class VcentersController extends ObjectsController
 {
     use AsyncControllerHelper;
 
-    protected function getConnectionsByVCenter()
+    /**
+     * @return ?array
+     */
+    protected function getConnectionsByVCenter(): ?array
     {
         try {
             $connections = $this->syncRpcCall('vsphere.getApiConnections');
-        } catch (\Exception $e) {
+        } catch (Exception) {
             return null;
         }
         $connectionState = new ConnectionState($connections, $this->db()->getDbAdapter());
@@ -33,9 +38,9 @@ protected function getConnectionsByVCenter()
     }
 
     /**
-     * @throws \Zend_Db_Select_Exception
+     * @throws Zend_Db_Select_Exception
      */
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->setAutorefreshInterval(15);
         $this->addSingleTab($this->translate('VCenters'));
@@ -79,7 +84,10 @@ public function indexAction()
         // $this->controls()->prepend($this->cpuSummary($table));
     }
 
-    protected function addNoVCenterHint()
+    /**
+     * @return void
+     */
+    protected function addNoVCenterHint(): void
     {
         $this->content()->add(Hint::warning(
             $this->translate('No vCenter available. You might want to check your %s or your %s'),
@@ -96,10 +104,12 @@ protected function addNoVCenterHint()
 
     /**
      * @param VCenterSummaryTable $table
+     *
      * @return CpuAbsoluteUsage
-     * @throws \Zend_Db_Select_Exception
+     *
+     * @throws Zend_Db_Select_Exception
      */
-    protected function cpuSummary(VCenterSummaryTable $table)
+    protected function cpuSummary(VCenterSummaryTable $table): CpuAbsoluteUsage
     {
         $query = clone($table->getQuery());
         $query->reset('columns')->reset('limitcount')->reset('limitoffset')->reset('group');
@@ -107,7 +117,7 @@ protected function cpuSummary(VCenterSummaryTable $table)
             'used_mhz'  => 'SUM(hqs.overall_cpu_usage)',
             'total_mhz' => 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)',
             'used_mb'   => 'SUM(hqs.overall_memory_usage_mb)',
-            'total_mb'  => 'SUM(h.hardware_memory_size_mb)',
+            'total_mb'  => 'SUM(h.hardware_memory_size_mb)'
         ]);
 
         $total = $this->db()->getDbAdapter()->fetchRow($query);
@@ -117,7 +127,10 @@ protected function cpuSummary(VCenterSummaryTable $table)
         );
     }
 
-    protected function handleTabs()
+    /**
+     * @return void
+     */
+    protected function handleTabs(): void
     {
         $action = $this->getRequest()->getControllerName();
         $tabs = $this->tabs(new MainTabs($this->Auth(), $this->db()));
@@ -128,7 +141,10 @@ protected function handleTabs()
         }
     }
 
-    protected function checkDaemonStatus()
+    /**
+     * @return void
+     */
+    protected function checkDaemonStatus(): void
     {
         $db = $this->db()->getDbAdapter();
         $daemon = $db->fetchRow(
@@ -152,7 +168,10 @@ protected function checkDaemonStatus()
         }
     }
 
-    protected function checkForMigrations()
+    /**
+     * @return void
+     */
+    protected function checkForMigrations(): void
     {
         if (Db::migrationsForDb($this->db())->hasPendingMigrations()) {
             $this->redirectNow('vspheredb/configuration/database');
diff --git a/application/controllers/VmController.php b/application/controllers/VmController.php
index 730b7d7e..ec2d7830 100644
--- a/application/controllers/VmController.php
+++ b/application/controllers/VmController.php
@@ -9,6 +9,7 @@
 use Icinga\Module\Vspheredb\DbObject\VmQuickStats;
 use Icinga\Module\Vspheredb\Web\Controller;
 use Icinga\Module\Vspheredb\Web\Table\AlarmHistoryTable;
+use Icinga\Module\Vspheredb\Web\Table\EventHistoryTable;
 use Icinga\Module\Vspheredb\Web\Table\Object\VmEssentialInfoTable;
 use Icinga\Module\Vspheredb\Web\Table\Object\VmExtraInfoTable;
 use Icinga\Module\Vspheredb\Web\Table\Object\VmLocationInfoTable;
@@ -16,7 +17,6 @@
 use Icinga\Module\Vspheredb\Web\Table\VmDisksTable;
 use Icinga\Module\Vspheredb\Web\Table\VmDiskUsageTable;
 use Icinga\Module\Vspheredb\Web\Table\VmNetworkAdapterTable;
-use Icinga\Module\Vspheredb\Web\Table\EventHistoryTable;
 use Icinga\Module\Vspheredb\Web\Table\VmSnapshotTable;
 use Icinga\Module\Vspheredb\Web\Widget\CustomValueDetails;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
@@ -25,6 +25,7 @@
 use Icinga\Module\Vspheredb\Web\Widget\VmHardwareTree;
 use Icinga\Module\Vspheredb\Web\Widget\VmHeader;
 use Icinga\Module\Vspheredb\Web\Widget\VmRouteConfigTable;
+use ipl\Html\Attributes;
 
 class VmController extends Controller
 {
@@ -35,12 +36,10 @@ class VmController extends Controller
      * @throws MissingParameterException
      * @throws NotFoundError
      */
-    public function indexAction()
+    public function indexAction(): void
     {
         $vm = $this->addVm();
-        $this->content()->addAttributes([
-            'class' => 'vm-info'
-        ]);
+        $this->content()->addAttributes(Attributes::create(['class' => 'vm-info']));
         $vCenter = VCenter::load($vm->get('vcenter_uuid'), $vm->getConnection());
         $this->addSections([
             new VmEssentialInfoTable($vm),
@@ -54,26 +53,26 @@ public function indexAction()
             new VmDiskUsageTable($vm),
             new VmSnapshotTable($vm),
             new BackupToolInfo($vm),
-            new VmExtraInfoTable($vm),
+            new VmExtraInfoTable($vm)
         ]);
     }
 
     /**
      * @throws MissingParameterException|NotFoundError
      */
-    public function hardwareAction()
+    public function hardwareAction(): void
     {
         $vm = $this->addVm();
         $this->content()->add([
             new SubTitle($this->translate('Hardware'), 'print'),
-            new VmHardwareTree($vm),
+            new VmHardwareTree($vm)
         ]);
     }
 
     /**
      * @throws MissingParameterException|NotFoundError
      */
-    public function eventsAction()
+    public function eventsAction(): void
     {
         $table = new EventHistoryTable($this->db());
         $table->filterVm($this->addVm())->renderTo($this);
@@ -82,35 +81,39 @@ public function eventsAction()
     /**
      * @throws MissingParameterException|NotFoundError
      */
-    public function alarmsAction()
+    public function alarmsAction(): void
     {
         $table = new AlarmHistoryTable($this->db());
         $table->filterEntityUuid($this->addVm()->get('uuid'))->renderTo($this);
     }
 
-    public function monitoringAction()
+    public function monitoringAction(): void
     {
         $this->showMonitoringDetails($this->addVm());
     }
 
     /**
      * @return VirtualMachine
+     *
      * @throws MissingParameterException
      * @throws NotFoundError
      */
-    protected function addVm()
+    protected function addVm(): VirtualMachine
     {
         $vm = VirtualMachine::loadWithUuid($this->params->getRequired('uuid'), $this->db());
         $this->getRestrictionHelper()->assertAccessToVCenterUuidIsGranted($vm->get('vcenter_uuid'));
         $this->controls()->add(new VmHeader($vm, VmQuickStats::loadFor($vm)));
-        $this->controls()->addAttributes(['class' => 'controls-with-object-header']);
+        $this->controls()->addAttributes(Attributes::create(['class' => 'controls-with-object-header']));
         $this->setTitle($vm->object()->get('object_name'));
         $this->handleTabs();
 
         return $vm;
     }
 
-    protected function handleTabs()
+    /**
+     * @return void
+     */
+    protected function handleTabs(): void
     {
         $params = ['uuid' => $this->params->get('uuid')];
         $this->tabs()->add('index', [
diff --git a/application/controllers/VmsController.php b/application/controllers/VmsController.php
index c22845a4..cf53cb7f 100644
--- a/application/controllers/VmsController.php
+++ b/application/controllers/VmsController.php
@@ -14,12 +14,12 @@
 
 class VmsController extends ObjectsController
 {
-    protected $otherTabActions = [
+    protected array $otherTabActions = [
         'diskusage' => 'index',
-        'snapshot'  => 'index',
+        'snapshot'  => 'index'
     ];
 
-    public function indexAction()
+    public function indexAction(): void
     {
         $this->handleTabs();
         $this->addTreeViewToggle();
@@ -43,7 +43,7 @@ public function indexAction()
                 'vspheredb/vms/snapshot',
                 $urlParams,
                 ['class' => 'icon-database']
-            ),
+            )
         ]);
 
         $this->setAutorefreshInterval(15);
@@ -59,12 +59,12 @@ public function indexAction()
         $this->content()->prepend($summaries);
     }
 
-    public function exportAction()
+    public function exportAction(): void
     {
         $this->sendExport('virtual_machine');
     }
 
-    public function diskusageAction()
+    public function diskusageAction(): void
     {
         $this->handleTabs();
 
@@ -81,7 +81,7 @@ public function diskusageAction()
                 'vspheredb/vms/snapshot',
                 $urlParams,
                 ['class' => 'icon-database']
-            ),
+            )
         ]);
         $table = new VmsGuestDiskUsageTable($this->db(), $this->url());
         (new AdditionalTableActions($table, Auth::getInstance(), $this->url()))
@@ -89,7 +89,7 @@ public function diskusageAction()
         $this->showTable($table, 'vspheredb/vms', $this->translate('Virtual Machine Guest Disks'));
     }
 
-    public function snapshotAction()
+    public function snapshotAction(): void
     {
         $this->handleTabs();
         $urlParams = $this->getParentParamsToPreserve();
@@ -105,7 +105,7 @@ public function snapshotAction()
                 'vspheredb/vms',
                 $urlParams,
                 ['class' => 'icon-left-small']
-            ),
+            )
         ]);
         $table = new VmsSnapshotsTable($this->db(), $this->url());
         (new AdditionalTableActions($table, Auth::getInstance(), $this->url()))
diff --git a/library/Vspheredb/Addon/BackupTool.php b/library/Vspheredb/Addon/BackupTool.php
index f2d419da..e040167c 100644
--- a/library/Vspheredb/Addon/BackupTool.php
+++ b/library/Vspheredb/Addon/BackupTool.php
@@ -2,9 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\Addon;
 
-use Icinga\Module\Vspheredb\DbObject\CustomValues;
-use ipl\Html\HtmlDocument;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
+use ipl\Html\HtmlDocument;
 
 /**
  * Interface BackupTool
@@ -20,21 +19,24 @@ interface BackupTool
     /**
      * @return string
      */
-    public function getName();
+    public function getName(): string;
 
     /**
      * @param VirtualMachine $vm
+     *
      * @return bool
      */
-    public function wants(VirtualMachine $vm);
+    public function wants(VirtualMachine $vm): bool;
 
     /**
      * @param VirtualMachine $vm
+     *
+     * @return void
      */
-    public function handle(VirtualMachine $vm);
+    public function handle(VirtualMachine $vm): void;
 
     /**
-     * @return HtmlDocument|null
+     * @return ?HtmlDocument
      */
-    public function getInfoRenderer();
+    public function getInfoRenderer(): ?HtmlDocument;
 }
diff --git a/library/Vspheredb/Addon/IbmSpectrumProtect.php b/library/Vspheredb/Addon/IbmSpectrumProtect.php
index 6481c1e3..a1d6ea8b 100644
--- a/library/Vspheredb/Addon/IbmSpectrumProtect.php
+++ b/library/Vspheredb/Addon/IbmSpectrumProtect.php
@@ -12,26 +12,32 @@ class IbmSpectrumProtect implements BackupTool
 
     public const CLOSE_TAG = '</Last Backup>';
 
-    protected $lastAttributes;
+    protected ?array $lastAttributes = null;
 
-    public function getName()
+    /**
+     * @return string
+     */
+    public function getName(): string
     {
         return 'IBM Spectrum Protect';
     }
 
     /**
      * @param VirtualMachine $vm
+     *
      * @return bool
      */
-    public function wants(VirtualMachine $vm)
+    public function wants(VirtualMachine $vm): bool
     {
         return $this->wantsAnnotation($vm->get('annotation'));
     }
 
     /**
      * @param VirtualMachine $vm
+     *
+     * @return void
      */
-    public function handle(VirtualMachine $vm)
+    public function handle(VirtualMachine $vm): void
     {
         $this->parseAnnotation($vm->get('annotation'));
     }
@@ -39,24 +45,25 @@ public function handle(VirtualMachine $vm)
     /**
      * @return IbmSpectrumProtectBackupRunDetails
      */
-    public function getInfoRenderer()
+    public function getInfoRenderer(): IbmSpectrumProtectBackupRunDetails
     {
         return new IbmSpectrumProtectBackupRunDetails($this);
     }
 
     /**
      * @param $annotation
+     *
      * @return bool
      */
-    public function wantsAnnotation($annotation)
+    public function wantsAnnotation($annotation): bool
     {
-        return $annotation !== null && strpos($annotation, static::OPEN_TAG) !== false;
+        return $annotation !== null && str_contains($annotation, static::OPEN_TAG);
     }
 
     /**
      * @return array
      */
-    public function requireParsedAttributes()
+    public function requireParsedAttributes(): array
     {
         $attributes = $this->getAttributes();
         if ($attributes === null) {
@@ -67,14 +74,19 @@ public function requireParsedAttributes()
     }
 
     /**
-     * @return array|null
+     * @return ?array
      */
-    public function getAttributes()
+    public function getAttributes(): ?array
     {
         return $this->lastAttributes;
     }
 
-    protected function parseAnnotation($annotation)
+    /**
+     * @param string $annotation
+     *
+     * @return void
+     */
+    protected function parseAnnotation(string $annotation): void
     {
         $beginPos = strpos($annotation, static::OPEN_TAG);
         if ($beginPos === false) {
@@ -104,25 +116,27 @@ protected function parseAnnotation($annotation)
         ];
 
         foreach ($lines as $line) {
-            if (strpos($line, '=') === false) {
+            if (! str_contains($line, '=')) {
                 continue;
             }
-            [$key, $value] = preg_split('/=/', $line, 2);
-            if ($key === 'Last Run Time') {
-                $attributes[$key] = static::parseTime($value);
-            } elseif ($key === 'Data Transmitted') {
-                $attributes[$key] = static::parseBytes($value);
-            } elseif ($key === 'Duration') {
-                $attributes[$key] = static::parseDuration($value);
-            } else {
-                $attributes[$key] = static::parseString($value);
-            }
+            [$key, $value] = explode('=', $line, 2);
+            $attributes[$key] = match ($key) {
+                'Last Run Time'    => static::parseTime($value),
+                'Data Transmitted' => static::parseBytes($value),
+                'Duration'         => static::parseDuration($value),
+                default            => static::parseString($value)
+            };
         }
 
         $this->lastAttributes = $attributes;
     }
 
-    public function stripAnnotation(&$annotation)
+    /**
+     * @param string $annotation
+     *
+     * @return void
+     */
+    public function stripAnnotation(string &$annotation): void
     {
         $beginPos = strpos($annotation, static::OPEN_TAG);
         if ($beginPos === false) {
@@ -131,15 +145,15 @@ public function stripAnnotation(&$annotation)
         $begin = $beginPos + strlen(static::OPEN_TAG) + 1;
         $end = strpos($annotation, static::CLOSE_TAG, $begin);
 
-        $annotation = substr($annotation, 0, $beginPos)
-            . substr($annotation, $end + strlen(static::CLOSE_TAG));
+        $annotation = substr($annotation, 0, $beginPos) . substr($annotation, $end + strlen(static::CLOSE_TAG));
     }
 
     /**
-     * @param $string
-     * @return string|null
+     * @param string $string
+     *
+     * @return ?string
      */
-    public static function parseString($string)
+    public static function parseString(string $string): ?string
     {
         if (strlen($string) < 2) {
             return $string;
@@ -147,30 +161,32 @@ public static function parseString($string)
 
         if (preg_match("/^'(.*)'$/", $string, $match)) {
             return $match[1];
-        } else {
-            // Be strict. Otherwise we could of course return $string.
-            return null;
         }
+
+        // Be strict. Otherwise we could of course return $string.
+        return null;
     }
 
-    public static function parseDuration($value)
+    /**
+     * @param string $value
+     *
+     * @return float|int|null
+     */
+    public static function parseDuration(string $value): float|int|null
     {
-        if (
-            preg_match(
-                '/^(\d{2}):(\d{2}):(\d{2})$/',
-                static::parseString($value),
-                $match
-            )
-        ) {
-            return intval($match[1]) * 3600
-                + intval($match[2]) * 60
-                + intval($match[3]);
-        } else {
-            return null;
+        if (preg_match('/^(\d{2}):(\d{2}):(\d{2})$/', static::parseString($value), $match)) {
+            return intval($match[1]) * 3600 + intval($match[2]) * 60 + intval($match[3]);
         }
+
+        return null;
     }
 
-    public static function parseBytes($value)
+    /**
+     * @param string $value
+     *
+     * @return ?int
+     */
+    public static function parseBytes(string $value): ?int
     {
         $value = static::parseString($value);
         if ($value === null) {
@@ -182,21 +198,22 @@ public static function parseBytes($value)
             'KB' => 1024,
             'MB' => 1024 * 1024,
             'GB' => 1024 * 1024 * 1024,
-            'TB' => 1024 * 1024 * 1024 * 1024,
+            'TB' => 1024 * 1024 * 1024 * 1024
         ];
 
         if (preg_match('/^([0-9\.]+)\s+(B|KB|MB|GB|TB)$/', $value, $match)) {
             return (int) (sscanf($match[1], '%f')[0] * $byteMultipliers[$match[2]]);
-        } else {
-            return null;
         }
+
+        return null;
     }
 
     /**
      * @param $time
-     * @return int|null
+     *
+     * @return ?int
      */
-    public static function parseTime($time)
+    public static function parseTime($time): ?int
     {
         $time = strtotime(static::parseString($time));
         if ($time === false) {
diff --git a/library/Vspheredb/Addon/NetBackup.php b/library/Vspheredb/Addon/NetBackup.php
index 58dff676..7c666201 100644
--- a/library/Vspheredb/Addon/NetBackup.php
+++ b/library/Vspheredb/Addon/NetBackup.php
@@ -14,12 +14,16 @@ class NetBackup extends SimpleBackupTool
 
     public const CV_EXCLUDE = 'NB_EXCLUDE_FROM_BACKUP';
 
-    protected $customValues = [
+    /** @var string[] */
+    protected array $customValues = [
         self::CV_LAST_BACKUP,
         self::CV_EXCLUDE
     ];
 
-    public function getName()
+    /**
+     * @return string
+     */
+    public function getName(): string
     {
         return 'Veritas NetBackup';
     }
@@ -27,12 +31,17 @@ public function getName()
     /**
      * @return NetBackupRunDetails
      */
-    public function getInfoRenderer()
+    public function getInfoRenderer(): NetBackupRunDetails
     {
         return new NetBackupRunDetails($this);
     }
 
-    protected function parseCustomValues(CustomValues $values)
+    /**
+     * @param CustomValues $values
+     *
+     * @return void
+     */
+    protected function parseCustomValues(CustomValues $values): void
     {
         if ($values->has(self::CV_LAST_BACKUP)) {
             $this->parseLastBackup($values->get(self::CV_LAST_BACKUP));
@@ -42,10 +51,15 @@ protected function parseCustomValues(CustomValues $values)
         }
     }
 
-    protected function parseLastBackup($string)
+    /**
+     * @param string $string
+     *
+     * @return void
+     */
+    protected function parseLastBackup(string $string): void
     {
         // Sun Sep 13 00:27:42 2020 +0200,backuphost.name,jobname
-        $parts = \explode(',', $string);
+        $parts = explode(',', $string);
         $attributes = [];
         if (count($parts) === 3) {
             $attributes['Time'] = strtotime($parts[0]);
diff --git a/library/Vspheredb/Addon/SimpleBackupTool.php b/library/Vspheredb/Addon/SimpleBackupTool.php
index 7eb5eabb..eb7c4196 100644
--- a/library/Vspheredb/Addon/SimpleBackupTool.php
+++ b/library/Vspheredb/Addon/SimpleBackupTool.php
@@ -10,9 +10,13 @@ abstract class SimpleBackupTool implements BackupTool
 {
     public const PREFIX = 'no-such-prefix';
 
-    protected $lastAttributes;
+    /**
+     * @var ?array
+     */
+    protected ?array $lastAttributes = null;
 
-    protected $customValues = [];
+    /** @var string[] */
+    protected array $customValues = [];
 
     /**
      * @return string[]
@@ -24,17 +28,20 @@ protected function getCustomValues(): array
 
     /**
      * @param $annotation
+     *
      * @return bool
      */
-    public function wantsAnnotation($annotation)
+    public function wantsAnnotation($annotation): bool
     {
-        return $annotation !== null && strpos($annotation, static::PREFIX) !== false;
+        return $annotation !== null && str_contains($annotation, static::PREFIX);
     }
 
     /**
      * @param VirtualMachine $vm
+     *
+     * @return void
      */
-    public function handle(VirtualMachine $vm)
+    public function handle(VirtualMachine $vm): void
     {
         $this->parseAnnotation($vm->get('annotation'));
         $this->parseCustomValues($vm->customValues());
@@ -45,7 +52,7 @@ public function handle(VirtualMachine $vm)
      *
      * @param CustomValues $values
      */
-    protected function parseCustomValues(CustomValues $values)
+    protected function parseCustomValues(CustomValues $values): void
     {
         $attributes = [];
         foreach ($this->getCustomValues() as $name) {
@@ -61,9 +68,10 @@ protected function parseCustomValues(CustomValues $values)
 
     /**
      * @param VirtualMachine $vm
+     *
      * @return bool
      */
-    public function wants(VirtualMachine $vm)
+    public function wants(VirtualMachine $vm): bool
     {
         $values = $vm->customValues();
         foreach ($this->getCustomValues() as $name) {
@@ -76,9 +84,9 @@ public function wants(VirtualMachine $vm)
     }
 
     /**
-     * @return array|null
+     * @return ?array
      */
-    public function getAttributes()
+    public function getAttributes(): ?array
     {
         return $this->lastAttributes;
     }
@@ -86,7 +94,7 @@ public function getAttributes()
     /**
      * @return array
      */
-    public function requireParsedAttributes()
+    public function requireParsedAttributes(): array
     {
         $attributes = $this->getAttributes();
         if ($attributes === null) {
@@ -96,7 +104,12 @@ public function requireParsedAttributes()
         return $attributes;
     }
 
-    protected function parseAnnotation($annotation)
+    /**
+     * @param ?string $annotation
+     *
+     * @return void
+     */
+    protected function parseAnnotation(?string $annotation): void
     {
         if ($annotation === null) {
             return;
@@ -119,7 +132,7 @@ protected function parseAnnotation($annotation)
         $parts = preg_split('/],\s/', rtrim($match, ']'));
         $attributes = [];
         foreach ($parts as $part) {
-            if (strpos($part, ': [') === false) {
+            if (! str_contains($part, ': [')) {
                 continue;
             }
             [$key, $value] = preg_split('/:\s\[/', $part, 2);
@@ -131,7 +144,12 @@ protected function parseAnnotation($annotation)
         $this->lastAttributes = $attributes;
     }
 
-    public function stripAnnotation(&$annotation)
+    /**
+     * @param string $annotation
+     *
+     * @return void
+     */
+    public function stripAnnotation(string &$annotation): void
     {
         $begin = strpos($annotation, static::PREFIX);
         if ($begin === false) {
@@ -143,18 +161,27 @@ public function stripAnnotation(&$annotation)
             $end = strlen($annotation);
         }
 
-        $annotation = substr($annotation, 0, $begin)
-        . substr($annotation, $end);
+        $annotation = substr($annotation, 0, $begin) . substr($annotation, $end);
     }
 
-    public function stripCustomValues(CustomValues $values)
+    /**
+     * @param CustomValues $values
+     *
+     * @return void
+     */
+    public function stripCustomValues(CustomValues $values): void
     {
         foreach ($this->getCustomValues() as $name) {
             $values->remove($name);
         }
     }
 
-    public function removeCustomValues(CustomValues $values)
+    /**
+     * @param CustomValues $values
+     *
+     * @return void
+     */
+    public function removeCustomValues(CustomValues $values): void
     {
         foreach ($this->getCustomValues() as $name) {
             $values->remove($name);
diff --git a/library/Vspheredb/Addon/VRangerBackup.php b/library/Vspheredb/Addon/VRangerBackup.php
index bae060b0..8b779103 100644
--- a/library/Vspheredb/Addon/VRangerBackup.php
+++ b/library/Vspheredb/Addon/VRangerBackup.php
@@ -8,9 +8,10 @@ class VRangerBackup extends SimpleBackupTool
 {
     public const PREFIX = 'vRanger Backup & Replication:';
 
-    protected $lastAttributes;
-
-    public function getName()
+    /**
+     * @return string
+     */
+    public function getName(): string
     {
         return 'vRanger Backup & Replication';
     }
@@ -18,12 +19,17 @@ public function getName()
     /**
      * @return VRangerBackupRunDetails
      */
-    public function getInfoRenderer()
+    public function getInfoRenderer(): VRangerBackupRunDetails
     {
         return new VRangerBackupRunDetails($this);
     }
 
-    protected function parseAnnotation($annotation)
+    /**
+     * @param ?string $annotation
+     *
+     * @return void
+     */
+    protected function parseAnnotation(?string $annotation): void
     {
         $this->lastAttributes = null;
         $begin = strpos($annotation, static::PREFIX);
diff --git a/library/Vspheredb/Addon/VeeamBackup.php b/library/Vspheredb/Addon/VeeamBackup.php
index 7e2f5f68..d55148a7 100644
--- a/library/Vspheredb/Addon/VeeamBackup.php
+++ b/library/Vspheredb/Addon/VeeamBackup.php
@@ -10,24 +10,30 @@ class VeeamBackup extends SimpleBackupTool
 {
     public const PREFIX = 'Veeam Backup: ';
 
-    public function getName()
+    /**
+     * @return string
+     */
+    public function getName(): string
     {
         return 'Veeam Backup & Replication';
     }
 
     /**
      * @param VirtualMachine $vm
+     *
      * @return bool
      */
-    public function wants(VirtualMachine $vm)
+    public function wants(VirtualMachine $vm): bool
     {
         return $this->wantsAnnotation($vm->get('annotation'));
     }
 
     /**
      * @param VirtualMachine $vm
+     *
+     * @return void
      */
-    public function handle(VirtualMachine $vm)
+    public function handle(VirtualMachine $vm): void
     {
         $this->parseAnnotation($vm->get('annotation'));
     }
@@ -35,7 +41,7 @@ public function handle(VirtualMachine $vm)
     /**
      * @return VeeamBackupRunDetails
      */
-    public function getInfoRenderer()
+    public function getInfoRenderer(): VeeamBackupRunDetails
     {
         return new VeeamBackupRunDetails($this);
     }
@@ -43,7 +49,7 @@ public function getInfoRenderer()
     /**
      * @return array
      */
-    public function requireParsedAttributes()
+    public function requireParsedAttributes(): array
     {
         $attributes = $this->getAttributes();
         if ($attributes === null) {
diff --git a/library/Vspheredb/Api/Protocol/ClientDecoder.php b/library/Vspheredb/Api/Protocol/ClientDecoder.php
index 6067300e..bd0b8d36 100644
--- a/library/Vspheredb/Api/Protocol/ClientDecoder.php
+++ b/library/Vspheredb/Api/Protocol/ClientDecoder.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Api\Protocol;
 
+use ReturnTypeWillChange;
 use SoapClient;
 use SoapFault;
 
@@ -13,17 +14,19 @@
  */
 final class ClientDecoder extends SoapClient
 {
-    private $response = null;
+    private ?string $response = null;
 
     /**
      * Decodes the SOAP response / return value from the given SOAP envelope (HTTP response body)
      *
      * @param string $function
      * @param string $response
+     *
      * @return mixed
+     *
      * @throws SoapFault if response indicates a fault (error condition) or is invalid
      */
-    public function decode($function, $response)
+    public function decode(string $function, string $response): mixed
     {
         // Temporarily save response internally for further processing
         $this->response = $response;
@@ -48,7 +51,7 @@ public function decode($function, $response)
      *
      * @see SoapClient::__doRequest()
      */
-    #[\ReturnTypeWillChange]
+    #[ReturnTypeWillChange]
     public function __doRequest($request, $location, $action, $version, $oneWay = 0, $uriParserClass = null)
     {
         // the actual result doesn't actually matter, just return the given result
diff --git a/library/Vspheredb/Api/Protocol/ClientEncoder.php b/library/Vspheredb/Api/Protocol/ClientEncoder.php
index fea558fc..cfbcc2b1 100644
--- a/library/Vspheredb/Api/Protocol/ClientEncoder.php
+++ b/library/Vspheredb/Api/Protocol/ClientEncoder.php
@@ -2,8 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\Api\Protocol;
 
-use SoapClient;
 use GuzzleHttp\Psr7\Request;
+use ReturnTypeWillChange;
+use SoapClient;
 use SoapFault;
 
 /**
@@ -14,17 +15,19 @@
  */
 final class ClientEncoder extends SoapClient
 {
-    private $request = null;
+    private ?Request $request = null;
 
     /**
      * Encodes the given RPC function name and arguments as a SOAP request
      *
      * @param string $name
      * @param array $args
+     *
      * @return Request
+     *
      * @throws SoapFault if request is invalid according to WSDL
      */
-    public function encode($name, $args)
+    public function encode(string $name, array $args): Request
     {
         $this->__soapCall($name, $args);
 
@@ -46,7 +49,7 @@ public function encode($name, $args)
      *
      * @see SoapClient::__doRequest()
      */
-    #[\ReturnTypeWillChange]
+    #[ReturnTypeWillChange]
     public function __doRequest($request, $location, $action, $version, $oneWay = 0, $uriParserClass = null)
     {
         $headers = [];
diff --git a/library/Vspheredb/Api/SoapClient.php b/library/Vspheredb/Api/SoapClient.php
index 3f7ab4b3..c76e53e8 100644
--- a/library/Vspheredb/Api/SoapClient.php
+++ b/library/Vspheredb/Api/SoapClient.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Api;
 
+use Exception;
 use gipfl\Curl\CurlAsync;
 use gipfl\Json\JsonEncodeException;
 use gipfl\Json\JsonString;
@@ -22,30 +23,32 @@
  */
 class SoapClient
 {
-    /** @var array */
-    protected $curlOptions;
+    protected array $curlOptions;
 
-    private $curl;
+    private CurlAsync $curl;
 
-    private $encoder;
+    private ClientEncoder $encoder;
 
-    private $decoder;
+    private ClientDecoder $decoder;
 
-    /** @var CookieStore */
-    protected $cookieStore;
+    protected ?CookieStore $cookieStore = null;
 
-    protected $logger;
+    protected LoggerInterface $logger;
 
     /**
-     * @param CurlAsync   $curl
-     * @param string|null $wsdl
-     * @param array       $options
+     * @param CurlAsync $curl
+     * @param ?string $wsdl
+     * @param array $options
+     * @param array $curlOptions
+     * @param ?LoggerInterface $logger
+     *
+     * @throws SoapFault
      */
     public function __construct(
         CurlAsync $curl,
-        $wsdl,
+        ?string $wsdl,
         array $options = [],
-        $curlOptions = [],
+        array $curlOptions = [],
         ?LoggerInterface $logger = null
     ) {
         $this->curl = $curl;
@@ -55,31 +58,29 @@ public function __construct(
         $this->logger = $logger ?: new NullLogger();
     }
 
-    public function setCookieStore(CookieStore $cookieStore)
+    public function setCookieStore(CookieStore $cookieStore): void
     {
         $this->cookieStore = $cookieStore;
     }
 
     /**
      * @param string $method
-     * @param mixed[] $args
+     * @param array $args
+     *
      * @return PromiseInterface<ResponseInterface>
      */
-    public function call($method, $args): PromiseInterface
+    public function call(string $method, array $args): PromiseInterface
     {
-        $request = $this->addCookiesToRequest(
-            $this->encoder->encode($method, $args),
-            $method
-        );
+        $request = $this->addCookiesToRequest($this->encoder->encode($method, $args), $method);
 
         return $this->curl->send($request, $this->curlOptions)
             ->then(function (ResponseInterface $response) use ($method) {
                 try {
-                    $result = $this->decoder->decode($method, (string)$response->getBody());
+                    $result = $this->decoder->decode($method, (string) $response->getBody());
                     $this->checkResponseForCookies($response);
 
                     return $result;
-                } catch (\Exception $e) {
+                } catch (Exception $e) {
                     if ($e instanceof SoapFault) {
                         if ($e->getMessage() === 'looks like we got no XML document') {
                             throw new SoapFault(
@@ -110,24 +111,22 @@ public function call($method, $args): PromiseInterface
                     $status = $response->getStatusCode();
 
                     if ($status > 199 && $status <= 299) {
-                        throw new \Exception($response->getReasonPhrase());
+                        throw new Exception($response->getReasonPhrase());
                     }
 
-                    $this->logger->error(
-                        'Failing Response: ' . $this->getBodyPart($response)
-                    );
+                    $this->logger->error('Failing Response: ' . $this->getBodyPart($response));
 
                     throw $e;
                 }
             });
     }
 
-    protected function getBodyPart(ResponseInterface $response)
+    protected function getBodyPart(ResponseInterface $response): string
     {
         return str_replace(["\r", "\n"], ['\\r', '\\n'], substr($response->getBody(), 0, 800));
     }
 
-    protected function addCookiesToRequest(RequestInterface $request, $soapFunctionName)
+    protected function addCookiesToRequest(RequestInterface $request, $soapFunctionName): RequestInterface
     {
         if ($this->cookieStore && $this->cookieStore->hasCookies()) {
             foreach ($this->cookieStore->getCookies() as $cookie) {
@@ -138,7 +137,7 @@ protected function addCookiesToRequest(RequestInterface $request, $soapFunctionN
         return $request;
     }
 
-    protected function checkResponseForCookies(ResponseInterface $response)
+    protected function checkResponseForCookies(ResponseInterface $response): void
     {
         if ($this->cookieStore) {
             $cookies = $response->getHeader('set-cookie');
diff --git a/library/Vspheredb/Application/Dependency.php b/library/Vspheredb/Application/Dependency.php
deleted file mode 100644
index 929a3f8f..00000000
--- a/library/Vspheredb/Application/Dependency.php
+++ /dev/null
@@ -1,113 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Application;
-
-class Dependency
-{
-    /** @var string */
-    protected $name;
-
-    /** @var string|null */
-    protected $installedVersion;
-
-    /** @var bool|null */
-    protected $enabled;
-
-    /** @var string */
-    protected $operator;
-
-    /** @var string */
-    protected $requiredVersion;
-
-    /** @var string */
-    protected $requirement;
-
-    /**
-     * Dependency constructor.
-     * @param string $name         Usually a module name
-     * @param string $requirement  e.g. >=1.7.0
-     * @param string $installedVersion
-     * @param bool $enabled
-     */
-    public function __construct($name, $requirement, $installedVersion = null, $enabled = null)
-    {
-        $this->name = $name;
-        $this->setRequirement($requirement);
-        if ($installedVersion !== null) {
-            $this->setInstalledVersion($installedVersion);
-        }
-        if ($enabled !== null) {
-            $this->setEnabled($enabled);
-        }
-    }
-
-    public function setRequirement($requirement)
-    {
-        if (preg_match('/^([<>=]+)\s*v?(\d+\.\d+\.\d+)$/', $requirement, $match)) {
-            $this->operator = $match[1];
-            $this->requiredVersion = $match[2];
-            $this->requirement = $requirement;
-        } else {
-            throw new \InvalidArgumentException("'$requirement' is not a valid version constraint");
-        }
-    }
-
-    /**
-     * @return bool
-     */
-    public function isInstalled()
-    {
-        return $this->installedVersion !== null;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getInstalledVersion()
-    {
-        return $this->installedVersion;
-    }
-
-    /**
-     * @param string $version
-     */
-    public function setInstalledVersion($version)
-    {
-        $this->installedVersion = ltrim($version, 'v'); // v0.6.0 VS 0.6.0
-    }
-
-    /**
-     * @return bool
-     */
-    public function isEnabled()
-    {
-        return $this->enabled === true;
-    }
-
-    /**
-     * @param bool $enabled
-     */
-    public function setEnabled($enabled = true)
-    {
-        $this->enabled = $enabled;
-    }
-
-    public function isSatisfied()
-    {
-        if (! $this->isInstalled() || ! $this->isEnabled()) {
-            return false;
-        }
-
-        return version_compare($this->installedVersion, $this->requiredVersion, $this->operator);
-    }
-
-    public function getName()
-    {
-        return $this->name;
-    }
-
-    public function getRequirement()
-    {
-        return $this->requirement;
-    }
-}
diff --git a/library/Vspheredb/Application/DependencyChecker.php b/library/Vspheredb/Application/DependencyChecker.php
deleted file mode 100644
index 27fbf17a..00000000
--- a/library/Vspheredb/Application/DependencyChecker.php
+++ /dev/null
@@ -1,73 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Application;
-
-use Icinga\Application\ApplicationBootstrap;
-use Icinga\Application\Modules\Module;
-use Icinga\Application\Version;
-
-class DependencyChecker
-{
-    /** @var ApplicationBootstrap */
-    protected $app;
-
-    /** @var \Icinga\Application\Modules\Manager */
-    protected $modules;
-
-    public function __construct(ApplicationBootstrap $app)
-    {
-        $this->app = $app;
-        $this->modules = $app->getModuleManager();
-    }
-
-    /**
-     * @param Module $module
-     * @return Dependency[]
-     */
-    public function getDependencies(Module $module)
-    {
-        $dependencies = [];
-        $isV290 = version_compare(Version::VERSION, '2.9.0', '>=');
-        foreach ($module->getDependencies() as $moduleName => $required) {
-            if ($isV290 && in_array($moduleName, ['ipl', 'reactbundle'], true)) {
-                continue;
-            }
-            $dependency = new Dependency($moduleName, $required);
-            $dependency->setEnabled($this->modules->hasEnabled($moduleName));
-            if ($this->modules->hasInstalled($moduleName)) {
-                $dependency->setInstalledVersion($this->modules->getModule($moduleName, false)->getVersion());
-            }
-            $dependencies[] = $dependency;
-        }
-        if ($isV290) {
-            $libs = $this->app->getLibraries();
-            foreach ($module->getRequiredLibraries() as $libraryName => $required) {
-                $dependency = new Dependency($libraryName, $required);
-                if ($libs->has($libraryName)) {
-                    $dependency->setInstalledVersion($libs->get($libraryName)->getVersion());
-                    $dependency->setEnabled();
-                }
-                $dependencies[] = $dependency;
-            }
-        }
-
-        return $dependencies;
-    }
-
-    //     if (version_compare(Version::VERSION, '2.9.0', 'ge')) {
-    //    }
-    /**
-     * @param Module $module
-     * @return bool
-     */
-    public function satisfiesDependencies(Module $module)
-    {
-        foreach ($this->getDependencies($module) as $dependency) {
-            if (! $dependency->isSatisfied()) {
-                return false;
-            }
-        }
-
-        return true;
-    }
-}
diff --git a/library/Vspheredb/Application/MemoryLimit.php b/library/Vspheredb/Application/MemoryLimit.php
index 04c4d04f..b7d12a3d 100644
--- a/library/Vspheredb/Application/MemoryLimit.php
+++ b/library/Vspheredb/Application/MemoryLimit.php
@@ -4,7 +4,12 @@
 
 class MemoryLimit
 {
-    public static function raiseTo($string)
+    /**
+     * @param string $string
+     *
+     * @return void
+     */
+    public static function raiseTo(string $string): void
     {
         $current = static::getBytes();
         $desired = static::parsePhpIniByteString($string);
@@ -13,7 +18,10 @@ public static function raiseTo($string)
         }
     }
 
-    public static function getBytes()
+    /**
+     * @return int
+     */
+    public static function getBytes(): int
     {
         return static::parsePhpIniByteString((string) ini_get('memory_limit'));
     }
@@ -27,10 +35,11 @@ public static function getBytes()
      * > (for Gigabytes), and are all case-insensitive. Anything else assumes
      * > bytes.
      *
-     * @param $string
+     * @param string $string
+     *
      * @return int
      */
-    public static function parsePhpIniByteString($string)
+    public static function parsePhpIniByteString(string $string): int
     {
         $val = trim($string);
 
diff --git a/library/Vspheredb/Auth/RestrictionHelper.php b/library/Vspheredb/Auth/RestrictionHelper.php
index 104fe752..84e0c0d0 100644
--- a/library/Vspheredb/Auth/RestrictionHelper.php
+++ b/library/Vspheredb/Auth/RestrictionHelper.php
@@ -10,18 +10,22 @@
 use Icinga\Module\Vspheredb\Db\DbUtil;
 use Icinga\Module\Vspheredb\Web\Table\TableWithVCenterFilter;
 use Ramsey\Uuid\Uuid;
+use Zend_Db_Adapter_Abstract;
+use Zend_Db_Select;
 
 class RestrictionHelper
 {
-    /** @var Auth */
-    protected $auth;
+    protected Auth $auth;
 
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
 
-    /** @var string[]|null */
-    protected $restrictedVCenterUuids = null;
+    /** @var ?string[] */
+    protected ?array $restrictedVCenterUuids = null;
 
+    /**
+     * @param Auth $auth
+     * @param Db $connection
+     */
     public function __construct(Auth $auth, Db $connection)
     {
         $this->db = $connection->getDbAdapter();
@@ -29,14 +33,25 @@ public function __construct(Auth $auth, Db $connection)
         $this->loadRestrictedVCenterList();
     }
 
-    public function restrictTable(TableWithVCenterFilter $table)
+    /**
+     * @param TableWithVCenterFilter $table
+     *
+     * @return void
+     */
+    public function restrictTable(TableWithVCenterFilter $table): void
     {
         if ($this->restrictedVCenterUuids) {
             $table->filterVCenterUuids($this->restrictedVCenterUuids);
         }
     }
 
-    public function filterQuery($query, $vCenterColumn = 'vcenter_uuid')
+    /**
+     * @param Zend_Db_Select $query
+     * @param string $vCenterColumn
+     *
+     * @return void
+     */
+    public function filterQuery(Zend_Db_Select $query, string $vCenterColumn = 'vcenter_uuid'): void
     {
         $uuids = $this->restrictedVCenterUuids;
         if ($uuids === null) {
@@ -49,14 +64,26 @@ public function filterQuery($query, $vCenterColumn = 'vcenter_uuid')
         }
     }
 
-    public function assertAccessToVCenterUuidIsGranted($uuid)
+    /**
+     * @param string $uuid
+     *
+     * @return void
+     *
+     * @throws NotFoundError
+     */
+    public function assertAccessToVCenterUuidIsGranted(string $uuid): void
     {
         if (! $this->allowsVCenter($uuid)) {
             throw new NotFoundError('Not found');
         }
     }
 
-    public function allowsVCenter($uuid): bool
+    /**
+     * @param string $uuid
+     *
+     * @return bool
+     */
+    public function allowsVCenter(string $uuid): bool
     {
         if ($this->restrictedVCenterUuids === null) {
             return true;
@@ -68,7 +95,10 @@ public function allowsVCenter($uuid): bool
         return in_array($uuid, $this->restrictedVCenterUuids);
     }
 
-    public function loadRestrictedVCenterList()
+    /**
+     * @return void
+     */
+    public function loadRestrictedVCenterList(): void
     {
         $uuids = null;
         $restrictions = $this->auth->getRestrictions('vspheredb/vcenters');
diff --git a/library/Vspheredb/CheckPluginHelper.php b/library/Vspheredb/CheckPluginHelper.php
index e4b21705..abdf3efe 100644
--- a/library/Vspheredb/CheckPluginHelper.php
+++ b/library/Vspheredb/CheckPluginHelper.php
@@ -3,67 +3,64 @@
 namespace Icinga\Module\Vspheredb;
 
 use Exception;
+use gipfl\Cli\AnsiScreen;
 use gipfl\Cli\Screen;
 use Icinga\Module\Vspheredb\Clicommands\Command;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
 use InvalidArgumentException;
 use React\Promise\PromiseInterface;
+use Throwable;
 
 trait CheckPluginHelper
 {
-    /** @var int */
-    protected $state = 0;
+    protected int $state = 0;
 
     protected $sortingState;
 
-    protected $sortingStateMap = [0, 1, 3, 2];
+    protected array $sortingStateMap = [0, 1, 3, 2];
 
-    protected $outputScreen;
+    protected AnsiScreen|Screen|null $outputScreen = null;
 
-    /** @var array */
-    protected $nameStateMap = [
+    protected array $nameStateMap = [
         'OK'       => 0,
         'WARNING'  => 1,
         'CRITICAL' => 2,
-        'UNKNOWN'  => 3,
+        'UNKNOWN'  => 3
     ];
 
-    /** @var array */
-    protected $stateNameMap = [
+    protected array $stateNameMap = [
         'OK',
         'WARNING',
         'CRITICAL',
-        'UNKNOWN',
+        'UNKNOWN'
     ];
 
-    protected $stateColors = [
+    protected array $stateColors = [
         'OK'       => 'green',
         'WARNING'  => 'brown',
         'CRITICAL' => 'red',
-        'UNKNOWN'  => 'purple',
+        'UNKNOWN'  => 'purple'
     ];
 
-    /** @var array */
-    protected $messages = [];
+    protected array $messages = [];
 
-    /** @var string|null */
-    protected $message;
+    protected ?string $message = null;
 
     /**
-     * @param $callable
+     * @param callable $callable
      */
-    protected function run($callable)
+    protected function run(callable $callable): void
     {
         /** @var Command $this */
         $this->loop()->futureTick(function () use ($callable) {
             $result = null;
-            if (\is_callable($callable)) {
+            if (is_callable($callable)) {
                 try {
                     $result = $callable();
                 } catch (Exception $e) {
                     $this->addProblem('UNKNOWN', $this->stripNonUtf8Characters($e->getMessage()));
                     $this->showOptionalTrace($e);
-                } catch (\Throwable $e) {
+                } catch (Throwable $e) {
                     $this->addProblem('UNKNOWN', $this->stripNonUtf8Characters($e->getMessage()));
                     $this->showOptionalTrace($e);
                 }
@@ -87,7 +84,7 @@ protected function run($callable)
         $this->eventuallyStartMainLoop();
     }
 
-    protected function showOptionalTrace($e)
+    protected function showOptionalTrace(Throwable $e): void
     {
         if ($this->showTrace()) {
             echo $e->getTraceAsString();
@@ -96,29 +93,32 @@ protected function showOptionalTrace($e)
 
     /**
      * @param string $string
+     *
      * @return string
      */
-    protected function stripNonUtf8Characters($string)
+    protected function stripNonUtf8Characters(string $string): string
     {
         return iconv('UTF-8', 'UTF-8//IGNORE', $string);
     }
 
     /**
      * @param int|string|null $state
+     *
      * @return string
      */
     protected function getStateName(int|string|null $state = null): string
     {
         if ($state === null) {
             return $this->stateNameMap[$this->state];
-        } else {
-            return $this->stateNameMap[$this->wantNumericState($state)];
         }
+
+        return $this->stateNameMap[$this->wantNumericState($state)];
     }
 
     /**
      * @param int|string $state
      * @param string $message
+     *
      * @return $this
      */
     protected function addProblem(int|string $state, string $message): static
@@ -134,20 +134,17 @@ protected function addProblem(int|string $state, string $message): static
         return $this;
     }
 
-    protected function getOutputScreen()
+    protected function getOutputScreen(): AnsiScreen|Screen
     {
-        if ($this->outputScreen === null) {
-            $this->outputScreen = Screen::factory();
-        }
-
-        return $this->outputScreen;
+        return $this->outputScreen ??= Screen::factory();
     }
 
     /**
      * @param string $message
+     *
      * @return $this
      */
-    protected function addMessage($message)
+    protected function addMessage(string $message): static
     {
         $this->messages[] = $message;
 
@@ -156,9 +153,10 @@ protected function addMessage($message)
 
     /**
      * @param string $message
+     *
      * @return $this
      */
-    protected function prependMessage($message)
+    protected function prependMessage(string $message): static
     {
         array_unshift($this->messages, $message);
 
@@ -167,6 +165,7 @@ protected function prependMessage($message)
 
     /**
      * @param int|string $state
+     *
      * @return $this
      */
     protected function raiseState(int|string $state): static
@@ -182,13 +181,14 @@ protected function raiseState(int|string $state): static
     /**
      * @return int
      */
-    protected function getState()
+    protected function getState(): int
     {
         return $this->state;
     }
 
     /**
      * @param int|string $state
+     *
      * @return int
      */
     protected function wantNumericState(int|string $state): int
@@ -196,24 +196,24 @@ protected function wantNumericState(int|string $state): int
         if (is_int($state) || ctype_digit($state)) {
             if (array_key_exists($state, $this->stateNameMap)) {
                 return (int) $state;
-            } else {
-                throw new InvalidArgumentException(sprintf('%d is not a valid numeric state', $state));
-            }
-        } else {
-            if (array_key_exists($state, $this->nameStateMap)) {
-                return $this->nameStateMap[$state];
-            } else {
-                throw new InvalidArgumentException(sprintf('%s is not a valid state name', $state));
             }
+
+            throw new InvalidArgumentException(sprintf('%d is not a valid numeric state', $state));
+        }
+
+        if (array_key_exists($state, $this->nameStateMap)) {
+            return $this->nameStateMap[$state];
         }
+
+        throw new InvalidArgumentException(sprintf('%s is not a valid state name', $state));
     }
 
-    protected function getMessages()
+    protected function getMessages(): array
     {
         return $this->messages;
     }
 
-    protected function shutdown()
+    protected function shutdown(): void
     {
         $messages = $this->getMessages();
         if (! empty($messages)) {
@@ -221,6 +221,7 @@ protected function shutdown()
         }
         $this->loop()->addTimer(0.01, function () {
             $this->loop()->stop();
+
             exit($this->getState());
         });
     }
diff --git a/library/Vspheredb/Configuration.php b/library/Vspheredb/Configuration.php
index 251fddc5..33cafe14 100644
--- a/library/Vspheredb/Configuration.php
+++ b/library/Vspheredb/Configuration.php
@@ -9,19 +9,11 @@ class Configuration
 {
     public const DEFAULT_SOCKET = '/run/icinga-vspheredb/vspheredb.sock';
 
-    private static $controlSocket;
+    private static ?string $controlSocket = null;
 
-    public static function getSocketPath()
+    public static function getSocketPath(): string
     {
-        if (self::$controlSocket === null) {
-            if ($path = getenv('VSPHEREDB_SOCKET')) {
-                static::setControlSocket($path);
-            } else {
-                static::setControlSocket(self::DEFAULT_SOCKET);
-            }
-        }
-
-        return self::$controlSocket;
+        return self::$controlSocket ??= getenv('VSPHEREDB_SOCKET') ?: self::DEFAULT_SOCKET;
     }
 
     /**
@@ -29,9 +21,9 @@ public static function getSocketPath()
      *
      * Used for testing reasons only. Set null to re-enable the default logic
      *
-     * @param $path
+     * @param string $path
      */
-    public static function setControlSocket($path)
+    public static function setControlSocket(string $path): void
     {
         self::$controlSocket = $path;
     }
diff --git a/library/Vspheredb/Daemon/ConfigWatch.php b/library/Vspheredb/Daemon/ConfigWatch.php
index 811a658b..1518b214 100644
--- a/library/Vspheredb/Daemon/ConfigWatch.php
+++ b/library/Vspheredb/Daemon/ConfigWatch.php
@@ -19,27 +19,24 @@ class ConfigWatch
 
     public const ON_CONFIG = 'dbConfig';
 
-    /** @var string */
-    protected $configFile;
+    protected string $configFile;
 
-    /** @var string */
-    protected $resourceConfigFile;
+    protected ?string $resourceConfigFile = null;
 
-    /** @var string|null */
-    protected $dbResourceName;
+    protected ?string $dbResourceName = null;
 
-    /** @var array|null */
-    protected $resourceConfig;
+    protected ?array $resourceConfig = null;
 
-    protected $interval = 3;
+    protected int $interval = 3;
 
-    /** @var TimerInterface */
-    protected $timer;
+    protected ?TimerInterface $timer = null;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected ?LoopInterface $loop = null;
 
-    public function __construct($dbResourceName = null)
+    /**
+     * @param ?string $dbResourceName
+     */
+    public function __construct(?string $dbResourceName = null)
     {
         $this->configFile = Config::module('vspheredb')->getConfigFile();
         if ($dbResourceName === null) {
@@ -51,8 +48,10 @@ public function __construct($dbResourceName = null)
 
     /**
      * @param LoopInterface $loop
+     *
+     * @return void
      */
-    public function run(LoopInterface $loop)
+    public function run(LoopInterface $loop): void
     {
         $this->loop = $loop;
         $check = function () {
@@ -62,7 +61,10 @@ public function run(LoopInterface $loop)
         $loop->futureTick($check);
     }
 
-    public function stop()
+    /**
+     * @return void
+     */
+    public function stop(): void
     {
         if ($this->timer) {
             $this->loop->cancelTimer($this->timer);
@@ -70,33 +72,40 @@ public function stop()
         }
     }
 
-    protected function checkForFreshConfig()
+    /**
+     * @return void
+     */
+    protected function checkForFreshConfig(): void
     {
         if ($this->configHasBeenChanged()) {
             $this->emit(self::ON_CONFIG, [$this->resourceConfig]);
         }
     }
 
-    protected function getResourceName()
+    /**
+     * @return ?string
+     */
+    protected function getResourceName(): ?string
     {
-        if ($this->dbResourceName) {
-            return $this->dbResourceName;
-        } else {
-            return $this->loadDbResourceName();
-        }
+        return $this->dbResourceName ?: $this->loadDbResourceName();
     }
 
-    protected function loadDbResourceName()
+    /**
+     * @return ?string
+     */
+    protected function loadDbResourceName(): ?string
     {
         $parsed = @parse_ini_file($this->configFile, true);
-        if (isset($parsed['db']['resource'])) {
-            return $parsed['db']['resource'];
-        } else {
-            return null;
-        }
+
+        return $parsed['db']['resource'] ?? null;
     }
 
-    protected function loadDbConfigFromDisk($name)
+    /**
+     * @param ?string $name
+     *
+     * @return ?array
+     */
+    protected function loadDbConfigFromDisk(?string $name): ?array
     {
         if ($name === null) {
             return null;
@@ -108,20 +117,23 @@ protected function loadDbConfigFromDisk($name)
             ksort($section);
 
             return $section;
-        } else {
-            return null;
         }
+
+        return null;
     }
 
-    protected function configHasBeenChanged()
+    /**
+     * @return bool
+     */
+    protected function configHasBeenChanged(): bool
     {
         $resource = $this->loadDbConfigFromDisk($this->loadDbResourceName());
         if ($resource !== $this->resourceConfig) {
             $this->resourceConfig = $resource;
 
             return true;
-        } else {
-            return false;
         }
+
+        return false;
     }
 }
diff --git a/library/Vspheredb/Daemon/ConnectionState.php b/library/Vspheredb/Daemon/ConnectionState.php
index 647ad466..b81f7f83 100644
--- a/library/Vspheredb/Daemon/ConnectionState.php
+++ b/library/Vspheredb/Daemon/ConnectionState.php
@@ -8,20 +8,19 @@
 use Icinga\Module\Vspheredb\Monitoring\Health\ApiConnectionInfo;
 use Icinga\Module\Vspheredb\Monitoring\Health\ServerConnectionInfo;
 use Icinga\Module\Vspheredb\Polling\ApiConnection;
+use Zend_Db_Adapter_Abstract;
 
 class ConnectionState
 {
-    /** @var array */
-    protected $daemonApiConnections;
+    protected array $daemonApiConnections;
 
-    /** @var Adapter|\Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected Adapter|Zend_Db_Adapter_Abstract $db;
 
     /**
      * @param ApiConnectionInfo[] $daemonApiConnections
-     * @param Adapter|\Zend_Db_Adapter_Abstract $db
+     * @param Zend_Db_Adapter_Abstract|Adapter $db
      */
-    public function __construct(array $daemonApiConnections, $db)
+    public function __construct(array $daemonApiConnections, Zend_Db_Adapter_Abstract|Adapter $db)
     {
         $this->daemonApiConnections = [];
         foreach ($daemonApiConnections as $connection) {
@@ -57,6 +56,9 @@ public function getConnectionsByVCenter(): array
         return $connectionsByVCenter;
     }
 
+    /**
+     * @return array
+     */
     protected function getConfiguredServersByVCenter(): array
     {
         $db = $this->db;
@@ -88,17 +90,22 @@ protected function getConfiguredServersByVCenter(): array
         return $result;
     }
 
+    /**
+     * @param ServerConnectionInfo $info
+     *
+     * @return string
+     */
     public static function describe(ServerConnectionInfo $info): string
     {
         $t = StaticTranslator::get();
         $state = $info->getState();
-        $label = $info->serverName;
-        $label = Anonymizer::anonymizeString($label);
-        $lastError = $info->apiConnection ? $info->apiConnection->lastErrorMessage : null;
+        $label = Anonymizer::anonymizeString($info->serverName);
+        $lastError = $info->apiConnection?->lastErrorMessage;
         if ($lastError) {
             $lastError = ": $lastError";
             $lastError = Anonymizer::anonymizeString($lastError);
         }
+
         switch ($state) {
             case 'unknown':
                 return sprintf(
@@ -106,41 +113,26 @@ public static function describe(ServerConnectionInfo $info): string
                     $label
                 ) . $lastError;
             case 'disabled':
-                return sprintf(
-                    $t->translate('Connections to %s have been disabled'),
-                    $label
-                );
+                return sprintf($t->translate('Connections to %s have been disabled'), $label);
             case ApiConnection::STATE_CONNECTED:
-                return sprintf(
-                    $t->translate('API connection with %s is fine'),
-                    $label
-                );
+                return sprintf($t->translate('API connection with %s is fine'), $label);
             case ApiConnection::STATE_LOGIN:
-                return sprintf(
-                    $t->translate('Trying to log in to %s'),
-                    $label
-                ) . $lastError;
+                return sprintf($t->translate('Trying to log in to %s'), $label) . $lastError;
             case ApiConnection::STATE_INIT:
-                return sprintf(
-                    $t->translate('Initializing API connection with %s'),
-                    $label
-                ) . $lastError;
+                return sprintf($t->translate('Initializing API connection with %s'), $label) . $lastError;
             case ApiConnection::STATE_FAILING:
-                return sprintf(
-                    $t->translate('API connection with %s is failing'),
-                    $label
-                ) . $lastError;
+                return sprintf($t->translate('API connection with %s is failing'), $label) . $lastError;
             case ApiConnection::STATE_STOPPING:
-                return sprintf(
-                    $t->translate('Stopping API connection with %s'),
-                    $label
-                ) . $lastError;
+                return sprintf($t->translate('Stopping API connection with %s'), $label) . $lastError;
             default:
                 return $t->translate("Unknown API connection state: $state") . $lastError;
         }
     }
 
-    public static function describeNoServer()
+    /**
+     * @return string
+     */
+    public static function describeNoServer(): string
     {
         return StaticTranslator::get()->translate('There is no configured server for this vCenter');
     }
diff --git a/library/Vspheredb/Daemon/ControlSocket.php b/library/Vspheredb/Daemon/ControlSocket.php
index 06954e39..f6dfbdc3 100644
--- a/library/Vspheredb/Daemon/ControlSocket.php
+++ b/library/Vspheredb/Daemon/ControlSocket.php
@@ -16,28 +16,36 @@ class ControlSocket implements EventEmitterInterface
 {
     use EventEmitterTrait;
 
-    /** @var string */
-    protected $path;
+    protected string $path;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected ?LoopInterface $loop = null;
 
-    /** @var UnixServer */
-    protected $server;
+    protected ?UnixServer $server = null;
 
-    public function __construct($path)
+    /**
+     * @param string $path
+     */
+    public function __construct(string $path)
     {
         $this->path = $path;
         $this->eventuallyRemoveSocketFile();
     }
 
-    public function run(LoopInterface $loop)
+    /**
+     * @param LoopInterface $loop
+     *
+     * @return void
+     */
+    public function run(LoopInterface $loop): void
     {
         $this->loop = $loop;
         $this->listen();
     }
 
-    protected function listen()
+    /**
+     * @return void
+     */
+    protected function listen(): void
     {
         $old = umask(0000);
         $server = new UnixServer('unix://' . $this->path, $this->loop);
@@ -46,17 +54,21 @@ protected function listen()
         $this->server = $server;
     }
 
-    public function shutdown()
+    /**
+     * @return void
+     */
+    public function shutdown(): void
     {
-        if ($this->server) {
-            $this->server->close();
-            $this->server = null;
-        }
+        $this->server?->close();
+        $this->server = null;
 
         $this->eventuallyRemoveSocketFile();
     }
 
-    protected function eventuallyRemoveSocketFile()
+    /**
+     * @return void
+     */
+    protected function eventuallyRemoveSocketFile(): void
     {
         if (file_exists($this->path)) {
             unlink($this->path);
diff --git a/library/Vspheredb/Daemon/DbCleanup.php b/library/Vspheredb/Daemon/DbCleanup.php
index 34246629..3095d70b 100644
--- a/library/Vspheredb/Daemon/DbCleanup.php
+++ b/library/Vspheredb/Daemon/DbCleanup.php
@@ -2,28 +2,30 @@
 
 namespace Icinga\Module\Vspheredb\Daemon;
 
-use gipfl\Log\Logger;
 use gipfl\ZfDb\Adapter\Adapter;
 use Psr\Log\LoggerInterface;
+use Zend_Db_Adapter_Abstract;
 
 class DbCleanup
 {
-    protected $db;
+    protected Adapter|Zend_Db_Adapter_Abstract $db;
 
-    /** @var Logger */
-    protected $logger;
+    protected LoggerInterface $logger;
 
     /**
-     * @param Adapter|\Zend_Db_Adapter_Abstract $db
+     * @param Adapter|Zend_Db_Adapter_Abstract $db
      * @param LoggerInterface $logger
      */
-    public function __construct($db, LoggerInterface $logger)
+    public function __construct(Adapter|Zend_Db_Adapter_Abstract $db, LoggerInterface $logger)
     {
         $this->db = $db;
         $this->logger = $logger;
     }
 
-    public function runForStartup()
+    /**
+     * @return void
+     */
+    public function runForStartup(): void
     {
         $this->logger->notice('Running DB cleanup (this could take some time)');
         $db = $this->db;
@@ -55,7 +57,10 @@ public function runForStartup()
         $this->logger->notice('DB has been cleaned up');
     }
 
-    public function runRegular()
+    /**
+     * @return void
+     */
+    public function runRegular(): void
     {
         $this->logger->notice('Running DB cleanup (this could take some time)');
         $db = $this->db;
@@ -65,12 +70,15 @@ public function runRegular()
         $this->logger->notice('DB has been cleaned up');
     }
 
-    protected function optimizeWhenDeleted($result)
+    /**
+     * @param int $result
+     *
+     * @return void
+     */
+    protected function optimizeWhenDeleted(int $result): void
     {
         if ($result > 0) {
-            $this->logger->info(
-                "Removed $result outdated daemon log lines, optimizing table"
-            );
+            $this->logger->info("Removed $result outdated daemon log lines, optimizing table");
             $this->db->query('OPTIMIZE TABLE vspheredb_daemonlog')->execute();
         }
     }
diff --git a/library/Vspheredb/Daemon/DbLogger.php b/library/Vspheredb/Daemon/DbLogger.php
index 580c2984..a2a9b3a3 100644
--- a/library/Vspheredb/Daemon/DbLogger.php
+++ b/library/Vspheredb/Daemon/DbLogger.php
@@ -11,6 +11,7 @@
 use Psr\Log\LoggerAwareTrait;
 use Ramsey\Uuid\Uuid;
 use SplStack;
+use Zend_Db_Adapter_Abstract;
 
 class DbLogger implements LogWriterWithContext, EventEmitterInterface
 {
@@ -21,19 +22,24 @@ class DbLogger implements LogWriterWithContext, EventEmitterInterface
 
     public const ERROR_PREFIX_LENGTH = 17;
 
-    protected $instance;
+    protected string $instance;
 
-    protected $db;
+    protected ?Zend_Db_Adapter_Abstract $db = null;
 
-    protected $queue;
+    protected SplStack $queue;
 
-    protected $fqdn;
+    protected string $fqdn;
 
-    protected $pid;
+    protected int $pid;
 
-    protected $lastTs = null;
+    protected ?int $lastTs = null;
 
-    public function __construct($instanceUuid, $fqdn, $pid)
+    /**
+     * @param string $instanceUuid
+     * @param string $fqdn
+     * @param int $pid
+     */
+    public function __construct(string $instanceUuid, string $fqdn, int $pid)
     {
         $this->instance = $instanceUuid;
         $this->fqdn = $fqdn;
@@ -41,7 +47,12 @@ public function __construct($instanceUuid, $fqdn, $pid)
         $this->queue = new SplStack();
     }
 
-    public function setDb(?Db $db = null)
+    /**
+     * @param ?Db $db
+     *
+     * @return void
+     */
+    public function setDb(?Db $db = null): void
     {
         if ($db === null) {
             $this->db = null;
@@ -51,7 +62,14 @@ public function setDb(?Db $db = null)
         }
     }
 
-    public function write($level, $message, $context = [])
+    /**
+     * @param string $level
+     * @param string $message
+     * @param array $context
+     *
+     * @return void
+     */
+    public function write($level, $message, $context = []): void
     {
         if (substr($message, 0, self::ERROR_PREFIX_LENGTH) === self::ERROR_PREFIX) {
             return;
@@ -67,7 +85,7 @@ public function write($level, $message, $context = [])
                 'timestamp' => $timestamp,
                 'level'     => $level,
                 'message'   => $message,
-                'context'   => $context,
+                'context'   => $context
             ]);
             if ($this->queue->count() > 100) {
                 $this->queue->pop();
@@ -79,7 +97,15 @@ public function write($level, $message, $context = [])
         $this->reallyWrite($timestamp, $level, $message, $context);
     }
 
-    protected function reallyWrite($timestamp, $level, $message, $context = [])
+    /**
+     * @param int $timestamp
+     * @param string $level
+     * @param string $message
+     * @param array $context
+     *
+     * @return void
+     */
+    protected function reallyWrite(int $timestamp, string $level, string $message, array $context = []): void
     {
         $params = [
             'instance_uuid' => $this->instance,
@@ -87,7 +113,7 @@ protected function reallyWrite($timestamp, $level, $message, $context = [])
             'pid'           => $this->pid,
             'fqdn'         => $this->fqdn,
             'level'         => $level,
-            'message'       => $message,
+            'message'       => $message
         ];
         if (isset($context['pid'])) {
             $params['pid'] = $context['pid'];
@@ -97,24 +123,23 @@ protected function reallyWrite($timestamp, $level, $message, $context = [])
         }
         if (isset($context['vcenter_uuid'])) {
             $uuid = $context['vcenter_uuid'];
-            if (strlen($uuid) === 16) {
-                $params['vcenter_uuid'] = $context['vcenter_uuid'];
-            } else {
-                $params['vcenter_uuid'] = Uuid::fromString($context['vcenter_uuid'])->getBytes();
-            }
+            $params['vcenter_uuid'] = strlen($uuid) === 16
+                ? $context['vcenter_uuid']
+                : Uuid::fromString($context['vcenter_uuid'])->getBytes();
         }
 
         try {
             $this->db->insert('vspheredb_daemonlog', $params);
         } catch (Exception $e) {
-            if ($this->logger) {
-                $this->logger->debug(self::ERROR_PREFIX . $e->getMessage());
-            }
+            $this->logger?->debug(self::ERROR_PREFIX . $e->getMessage());
             $this->emit('error', [$e]);
         }
     }
 
-    protected function flushQueue()
+    /**
+     * @return void
+     */
+    protected function flushQueue(): void
     {
         while (! $this->queue->isEmpty()) {
             $log = $this->queue->pop();
diff --git a/library/Vspheredb/Daemon/DbProcessRunner.php b/library/Vspheredb/Daemon/DbProcessRunner.php
index bfa9204c..bdd541f2 100644
--- a/library/Vspheredb/Daemon/DbProcessRunner.php
+++ b/library/Vspheredb/Daemon/DbProcessRunner.php
@@ -4,6 +4,7 @@
 
 use Evenement\EventEmitterInterface;
 use Evenement\EventEmitterTrait;
+use Exception;
 use gipfl\Process\FinishedProcessState;
 use gipfl\Process\ProcessKiller;
 use gipfl\Protocol\JsonRpc\Handler\NamespacedPacketHandler;
@@ -13,6 +14,7 @@
 use React\ChildProcess\Process;
 use React\EventLoop\LoopInterface;
 use React\Promise\Deferred;
+use React\Promise\PromiseInterface;
 use React\Stream\Util;
 use RuntimeException;
 
@@ -22,29 +24,30 @@ class DbProcessRunner implements EventEmitterInterface
 {
     use EventEmitterTrait;
 
-    /** @var LoopInterface $loop */
-    protected $loop;
+    protected ?LoopInterface $loop = null;
 
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    /** @var JsonRpcConnection */
-    protected $rpc;
+    protected ?JsonRpcConnection $rpc = null;
 
-    /** @var LogProxy */
-    protected $logProxy;
+    protected ?LogProxy $logProxy = null;
 
-    /** @var Process */
-    protected $process;
+    protected ?Process $process = null;
 
-    protected $queue = [];
+    protected array $queue = [];
 
+    /**
+     * @param LoggerInterface $logger
+     */
     public function __construct(LoggerInterface $logger)
     {
         $this->logger = $logger;
     }
 
-    public function stop()
+    /**
+     * @return void
+     */
+    public function stop(): void
     {
         if ($this->process) {
             $process = $this->process;
@@ -55,13 +58,22 @@ public function stop()
         }
     }
 
-    protected function removeProcess()
+    /**
+     * @return void
+     */
+    protected function removeProcess(): void
     {
         $this->process = null;
         $this->rpc = null;
     }
 
-    public function request($method, $params = [])
+    /**
+     * @param string $method
+     * @param array $params
+     *
+     * @return PromiseInterface
+     */
+    public function request(string $method, array $params = []): PromiseInterface
     {
         // return $this->rpc->request($method, $params);
         if ($this->rpc === null) {
@@ -74,14 +86,20 @@ public function request($method, $params = [])
         return $deferred->promise();
     }
 
-    protected function scheduleNextRequest()
+    /**
+     * @return void
+     */
+    protected function scheduleNextRequest(): void
     {
         $this->loop->futureTick(function () {
             $this->sendNextRequest();
         });
     }
 
-    protected function sendNextRequest()
+    /**
+     * @return void
+     */
+    protected function sendNextRequest(): void
     {
         if (empty($this->queue)) {
             return;
@@ -99,7 +117,12 @@ protected function sendNextRequest()
         });
     }
 
-    protected function rejectQueue(\Exception $e)
+    /**
+     * @param Exception $e
+     *
+     * @return void
+     */
+    protected function rejectQueue(Exception $e): void
     {
         foreach ($this->queue as $entry) {
             $entry[0]->reject($e);
@@ -107,7 +130,12 @@ protected function rejectQueue(\Exception $e)
         $this->queue = [];
     }
 
-    public function run(LoopInterface $loop)
+    /**
+     * @param LoopInterface $loop
+     *
+     * @return PromiseInterface
+     */
+    public function run(LoopInterface $loop): PromiseInterface
     {
         if ($this->process) {
             throw new RuntimeException('Process is already running');
diff --git a/library/Vspheredb/Daemon/IcingaCli.php b/library/Vspheredb/Daemon/IcingaCli.php
index bc41c062..7730965d 100644
--- a/library/Vspheredb/Daemon/IcingaCli.php
+++ b/library/Vspheredb/Daemon/IcingaCli.php
@@ -6,46 +6,58 @@
 use gipfl\Process\FinishedProcessState;
 use React\EventLoop\LoopInterface;
 use React\Promise\Deferred;
+use React\Promise\PromiseInterface;
 
 class IcingaCli
 {
     use EventEmitterTrait;
 
-    /** @var IcingaCliRunner */
-    protected $runner;
+    protected IcingaCliRunner $runner;
 
-    protected $arguments = [];
+    protected array $arguments = [];
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected ?LoopInterface $loop = null;
 
     public function __construct(?IcingaCliRunner $runner = null)
     {
-        if ($runner === null) {
-            $runner = IcingaCliRunner::forArgv();
-        }
-        $this->runner = $runner;
+        $this->runner = $runner ?? IcingaCliRunner::forArgv();
         $this->init();
     }
 
-    protected function init()
+    /**
+     * @return void
+     */
+    protected function init(): void
     {
         // Override this if you want.
     }
 
-    public function setArguments($arguments)
+    /**
+     * @param array $arguments
+     *
+     * @return $this
+     */
+    public function setArguments(array $arguments): static
     {
         $this->arguments = $arguments;
 
         return $this;
     }
 
-    public function getArguments()
+    /**
+     * @return array
+     */
+    public function getArguments(): array
     {
         return $this->arguments;
     }
 
-    public function run(LoopInterface $loop)
+    /**
+     * @param LoopInterface $loop
+     *
+     * @return PromiseInterface
+     */
+    public function run(LoopInterface $loop): PromiseInterface
     {
         $this->loop = $loop;
         $process = $this->runner->command($this->getArguments());
diff --git a/library/Vspheredb/Daemon/IcingaCliRpc.php b/library/Vspheredb/Daemon/IcingaCliRpc.php
index dbe6d3c4..1893f91d 100644
--- a/library/Vspheredb/Daemon/IcingaCliRpc.php
+++ b/library/Vspheredb/Daemon/IcingaCliRpc.php
@@ -9,22 +9,16 @@
 use React\Promise\Deferred;
 use React\Promise\PromiseInterface;
 
-use function React\Promise\resolve;
-
 class IcingaCliRpc extends IcingaCli
 {
-    /** @var IcingaCliRunner */
-    protected $runner;
-
-    /** @var JsonRpcConnection */
-    protected $rpc;
-
-    /** @var Deferred */
-    protected $waitingForRpc;
+    protected ?JsonRpcConnection $rpc = null;
 
-    protected $arguments = [];
+    protected ?Deferred $waitingForRpc = null;
 
-    protected function init()
+    /**
+     * @return void
+     */
+    protected function init(): void
     {
         $this->on('start', function (Process $process) {
             $netString = new StreamWrapper(
@@ -32,9 +26,7 @@ protected function init()
                 $process->stdin
             );
             $netString->on('error', function (Exception $e) {
-                if ($this->waitingForRpc) {
-                    $this->waitingForRpc->reject($e);
-                }
+                $this->waitingForRpc?->reject($e);
                 $this->emit('error', [$e]);
             });
             $this->rpc = new JsonRpcConnection($netString);
@@ -48,7 +40,7 @@ protected function init()
     /**
      * @return PromiseInterface <Connection>
      */
-    public function rpc()
+    public function rpc(): PromiseInterface
     {
         if (! $this->waitingForRpc) {
             $this->waitingForRpc = new Deferred();
diff --git a/library/Vspheredb/Daemon/IcingaCliRunner.php b/library/Vspheredb/Daemon/IcingaCliRunner.php
index c83a39e1..3e33adea 100644
--- a/library/Vspheredb/Daemon/IcingaCliRunner.php
+++ b/library/Vspheredb/Daemon/IcingaCliRunner.php
@@ -6,25 +6,26 @@
 
 class IcingaCliRunner
 {
-    /** @var string */
-    protected $binary;
+    protected string $binary;
 
-    /** @var string|null */
-    protected $cwd;
+    protected ?string $cwd = null;
 
-    /** @var array|null */
-    protected $env;
+    protected ?array $env = null;
 
-    public function __construct($binary)
+    /**
+     * @param string $binary
+     */
+    public function __construct(string $binary)
     {
         $this->binary = $binary;
     }
 
     /**
-     * @param array|null $argv
+     * @param ?array $argv
+     *
      * @return IcingaCliRunner
      */
-    public static function forArgv(?array $argv = null)
+    public static function forArgv(?array $argv = null): IcingaCliRunner
     {
         if ($argv === null) {
             global $argv;
@@ -35,13 +36,14 @@ public static function forArgv(?array $argv = null)
     }
 
     /**
-     * @param mixed array|...$arguments
+     * @param mixed $arguments array|...string
+     *
      * @return Process
      */
-    public function command($arguments = null)
+    public function command(...$arguments): Process
     {
-        if (! is_array($arguments)) {
-            $arguments = func_get_args();
+        if (count($arguments) === 1 && is_array($arguments[0])) {
+            $arguments = $arguments[0];
         }
 
         return new Process(
@@ -52,43 +54,36 @@ public function command($arguments = null)
     }
 
     /**
-     * @param string|null $cwd
+     * @param ?string $cwd
+     *
+     * @return void
      */
-    public function setCwd($cwd)
+    public function setCwd(?string $cwd): void
     {
-        if ($cwd === null) {
-            $this->cwd = $cwd;
-        } else {
-            $this->cwd = (string) $cwd;
-        }
+        $this->cwd = $cwd;
     }
 
     /**
-     * @param array|null $env
+     * @param ?array $env
+     *
+     * @return void
      */
-    public function setEnv($env)
+    public function setEnv(?array $env): void
     {
-        if ($env === null) {
-            $this->env = $env;
-        } else {
-            $this->env = (array) $env;
-        }
+        $this->env = $env;
     }
 
     /**
-     * @param $arguments
+     * @param array $arguments
+     *
      * @return string
      */
-    protected function escapedCommand($arguments)
+    protected function escapedCommand(array $arguments): string
     {
         $command = ['exec', escapeshellcmd($this->binary)];
 
         foreach ($arguments as $argument) {
-            if (ctype_alnum(preg_replace('/^\-{1,2}/', '', $argument))) {
-                $command[] = $argument;
-            } else {
-                $command[] = escapeshellarg($argument);
-            }
+            $command[] = ctype_alnum(preg_replace('/^\-{1,2}/', '', $argument)) ? $argument : escapeshellarg($argument);
         }
 
         return implode(' ', $command);
diff --git a/library/Vspheredb/Daemon/ObjectSync.php b/library/Vspheredb/Daemon/ObjectSync.php
index 205b39b2..625b69aa 100644
--- a/library/Vspheredb/Daemon/ObjectSync.php
+++ b/library/Vspheredb/Daemon/ObjectSync.php
@@ -44,24 +44,23 @@
 
 class ObjectSync implements DaemonTask
 {
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
-    /** @var VsphereApi */
-    protected $api;
+    protected VsphereApi $api;
 
     /** @var LoopInterface */
     protected $loop;
 
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    protected $fastTasks = [
+    /** @var string[] */
+    protected array $fastTasks = [
         HostQuickStatsSyncTask::class,
-        VmQuickStatsSyncTask::class,
+        VmQuickStatsSyncTask::class
     ];
 
-    protected $normalTasks = [
+    /** @var string[] */
+    protected array $normalTasks = [
         ManagedObjectReferenceSyncTask::class,
         HostSystemSyncTask::class,
         VirtualMachineSyncTask::class,
@@ -70,40 +69,47 @@ class ObjectSync implements DaemonTask
         ComputeResourceSyncTask::class,
         VmDiskUsageSyncTask::class,
         VmDatastoreUsageSyncTask::class,
-        VmSnapshotSyncTask::class,
+        VmSnapshotSyncTask::class
     ];
 
-    protected $slowTasks = [
+    /** @var string[] */
+    protected array $slowTasks = [
         HostHardwareSyncTask::class,
         HostSensorSyncTask::class,
         HostHbaSyncTask::class,
         HostPhysicalNicSyncTask::class,
         HostVirtualNicSyncTask::class,
-        VmHardwareSyncTask::class,
+        VmHardwareSyncTask::class
     ];
 
-    protected $taggingTasks = [
+    /** @var string[] */
+    protected array $taggingTasks = [
         TaggingTagSyncTask::class,
         TaggingObjectTagSyncTask::class,
-        TaggingCategorySyncTask::class,
+        TaggingCategorySyncTask::class
     ];
 
     /** @var TimerInterface[]  */
-    protected $timers = [];
+    protected array $timers = [];
 
     /** @var PromiseInterface[] */
-    protected $runningTasks = [];
+    protected array $runningTasks = [];
 
-    protected $ready = false;
+    protected bool $ready = false;
 
-    /** @var DbProcessRunner */
-    protected $dbRunner;
+    protected DbProcessRunner $dbRunner;
 
-    /** @var RestApi */
-    protected $restApi;
+    protected RestApi $restApi;
 
-    protected $logTaskNames = false;
+    protected bool $logTaskNames = false;
 
+    /**
+     * @param VCenter $vCenter
+     * @param VsphereApi $api
+     * @param RestApi $restApi
+     * @param DbProcessRunner $dbRunner
+     * @param LoggerInterface $logger
+     */
     public function __construct(
         VCenter $vCenter,
         VsphereApi $api,
@@ -121,20 +127,32 @@ public function __construct(
         $this->dbRunner = $dbRunner;
     }
 
-    protected function removeVCenterOnlyTasks()
+    /**
+     * @return void
+     */
+    protected function removeVCenterOnlyTasks(): void
     {
         $this->normalTasks = array_filter($this->normalTasks, function ($task) {
             return $task !== StoragePodSyncTask::class;
         });
     }
 
-    public function start(LoopInterface $loop)
+    /**
+     * @param LoopInterface $loop
+     *
+     * @return PromiseInterface
+     */
+    public function start(LoopInterface $loop): PromiseInterface
     {
         $this->loop = $loop;
+
         return $this->initialize();
     }
 
-    public function stop()
+    /**
+     * @return PromiseInterface
+     */
+    public function stop(): PromiseInterface
     {
         $this->ready = false;
         foreach ($this->timers as $timer) {
@@ -149,7 +167,10 @@ public function stop()
         return resolve(null);
     }
 
-    protected function initialize()
+    /**
+     * @return PromiseInterface
+     */
+    protected function initialize(): PromiseInterface
     {
         return $this->prepareSyncResultHandler()->then(function () {
             return $this->prepareEventPolling();
@@ -162,7 +183,10 @@ protected function initialize()
         });
     }
 
-    protected function scheduleTasks()
+    /**
+     * @return void
+     */
+    protected function scheduleTasks(): void
     {
         $this->timers[] = $this->loop->addPeriodicTimer(600, function () {
             // There might be new CustomValue definitions
@@ -192,7 +216,10 @@ protected function scheduleTasks()
         });
     }
 
-    protected function refreshOutdatedDatastores()
+    /**
+     * @return void
+     */
+    protected function refreshOutdatedDatastores(): void
     {
         $idx = VmDatastoreUsageSyncStore::class;
         $label = 'Refresh outdated VMs';
@@ -220,14 +247,22 @@ protected function refreshOutdatedDatastores()
         }
     }
 
-    protected function runTasks(array $tasks)
+    /**
+     * @param array $tasks
+     *
+     * @return void
+     */
+    protected function runTasks(array $tasks): void
     {
         foreach ($tasks as $task) {
             $this->runTask(new $task());
         }
     }
 
-    protected function runAllTasks()
+    /**
+     * @return void
+     */
+    protected function runAllTasks(): void
     {
         $this->runTasks(array_merge($this->fastTasks, $this->normalTasks, $this->slowTasks));
         $this->restApi->requireSession()->then(function () {
@@ -235,7 +270,12 @@ protected function runAllTasks()
         });
     }
 
-    protected function runTask(SyncTask $task)
+    /**
+     * @param SyncTask $task
+     *
+     * @return void
+     */
+    protected function runTask(SyncTask $task): void
     {
         $label = $task->getLabel();
         $idx = get_class($task);
@@ -274,7 +314,7 @@ protected function runTask(SyncTask $task)
                 'result'      => $result,
                 'taskLabel'   => $task->getLabel(),
                 'storeClass'  => $task->getSyncStoreClass(),
-                'objectClass' => $task->getObjectClass(),
+                'objectClass' => $task->getObjectClass()
             ])->then(function ($stats) use ($idx, $label) {
                 $stats = SyncStats::fromSerialization($stats);
                 if ($stats->hasChanges()) {
@@ -298,7 +338,10 @@ protected function runTask(SyncTask $task)
         });
     }
 
-    protected function prepareEventPolling()
+    /**
+     * @return PromiseInterface
+     */
+    protected function prepareEventPolling(): PromiseInterface
     {
         return $this->dbRunner->request('db.getLastEventTimeStamp', [
             'vCenterId' => $this->vCenter->get('id')
@@ -310,9 +353,9 @@ protected function prepareEventPolling()
     /**
      * Refreshes the custom fields map in the DB process
      *
-     * @return \React\Promise\PromiseInterface
+     * @return PromiseInterface
      */
-    protected function prepareSyncResultHandler()
+    protected function prepareSyncResultHandler(): PromiseInterface
     {
         return $this->api->fetchCustomFieldsManager()->then(function (?CustomFieldsManager $manager = null) {
             if ($manager === null) {
@@ -321,7 +364,7 @@ protected function prepareSyncResultHandler()
 
             return $this->dbRunner->request('db.setCustomFieldsMap', [
                 'vCenterId' => $this->vCenter->get('id'),
-                'map'       => $manager->requireMap(),
+                'map'       => $manager->requireMap()
             ]);
         });
     }
diff --git a/library/Vspheredb/Daemon/PerfDataSync.php b/library/Vspheredb/Daemon/PerfDataSync.php
index e2835cfe..cdb3cea3 100644
--- a/library/Vspheredb/Daemon/PerfDataSync.php
+++ b/library/Vspheredb/Daemon/PerfDataSync.php
@@ -35,36 +35,39 @@
 use Ramsey\Uuid\UuidInterface;
 use React\EventLoop\LoopInterface;
 use React\EventLoop\TimerInterface;
+use React\Promise\PromiseInterface;
 use stdClass;
 use Throwable;
+use Zend_Db_Adapter_Abstract;
 
 use function React\Promise\resolve;
 
 class PerfDataSync implements DaemonTask
 {
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
-    /** @var VsphereApi */
-    protected $api;
+    protected VsphereApi $api;
 
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    /** @var CurlAsync */
-    protected $curl;
+    protected CurlAsync $curl;
 
-    /** @var ChunkedInfluxDbWriter */
-    protected $influxDbWriter;
+    protected ?ChunkedInfluxDbWriter $influxDbWriter = null;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
     /** @var TimerInterface[]  */
-    protected $timers = [];
+    protected array $timers = [];
 
-    protected $loadingWriterConfig = false;
+    protected bool $loadingWriterConfig = false;
 
+    /**
+     * @param VCenter $vCenter
+     * @param VsphereApi $api
+     * @param CurlAsync $curl
+     * @param LoopInterface $loop
+     * @param LoggerInterface $logger
+     */
     public function __construct(
         VCenter $vCenter,
         VsphereApi $api,
@@ -79,7 +82,12 @@ public function __construct(
         $this->logger = $logger;
     }
 
-    public function start(LoopInterface $loop)
+    /**
+     * @param LoopInterface $loop
+     *
+     * @return PromiseInterface
+     */
+    public function start(LoopInterface $loop): PromiseInterface
     {
         $this->loop = $loop;
         $loop->futureTick(function () {
@@ -89,7 +97,10 @@ public function start(LoopInterface $loop)
         return resolve(null);
     }
 
-    public function stop()
+    /**
+     * @return PromiseInterface
+     */
+    public function stop(): PromiseInterface
     {
         foreach ($this->timers as $timer) {
             $this->loop->cancelTimer($timer);
@@ -99,7 +110,10 @@ public function stop()
         return resolve(null);
     }
 
-    protected function loadWriterConfig()
+    /**
+     * @return PromiseInterface
+     */
+    protected function loadWriterConfig(): PromiseInterface
     {
         if ($this->loadingWriterConfig) {
             return resolve(null);
@@ -109,6 +123,7 @@ protected function loadWriterConfig()
         if (! $loader) {
             $this->stopRunningInfluxDbInstances();
             $this->loadingWriterConfig = false;
+
             return resolve(null);
         }
         return $loader->then(function (?ChunkedInfluxDbWriter $writer) {
@@ -129,15 +144,19 @@ protected function loadWriterConfig()
         });
     }
 
-    protected function stopRunningInfluxDbInstances()
+    /**
+     * @return void
+     */
+    protected function stopRunningInfluxDbInstances(): void
     {
-        if ($this->influxDbWriter) {
-            $this->influxDbWriter->stop();
-            $this->influxDbWriter = null;
-        }
+        $this->influxDbWriter?->stop();
+        $this->influxDbWriter = null;
     }
 
-    protected function initialize()
+    /**
+     * @return void
+     */
+    protected function initialize(): void
     {
         $this->syncCounterInfo()->then(function () {
             $this->loadWriterConfig();
@@ -149,15 +168,17 @@ protected function initialize()
 
     /**
      * @param $spec
-     * @return \React\Promise\PromiseInterface <PerfEntityMetricCSV[]>
+     *
+     * @return PromiseInterface <PerfEntityMetricCSV[]>
      */
-    protected function queryPerf($spec)
+    protected function queryPerf($spec): PromiseInterface
     {
         return $this->api->callOnServiceInstanceObject('perfManager', 'QueryPerf', [
             'querySpec' => $spec
         ])->then(function ($result) {
             if (!isset($result->returnval)) {
                 $this->logger->warning('Got no returnval when fetching performance data');
+
                 return [];
             }
 
@@ -165,22 +186,33 @@ protected function queryPerf($spec)
         });
     }
 
+    /**
+     * @param Zend_Db_Adapter_Abstract $db
+     * @param UuidInterface $vCenterUuid
+     * @param PerformanceSet $set
+     * @param CounterLookup $counterLookup
+     * @param ?int $count
+     *
+     * @return void
+     */
     protected function fetchPerf(
-        $db,
+        Zend_Db_Adapter_Abstract $db,
         UuidInterface $vCenterUuid,
         PerformanceSet $set,
         CounterLookup $counterLookup,
-        $count
-    ) {
+        ?int $count
+    ): void {
         $tags = $counterLookup->fetchTags($vCenterUuid);
         $counterMap = CounterMap::fetchCounters($db, $set, $vCenterUuid);
         if (empty($counterMap)) {
             $this->logger->notice('Got no counters, nothing to do');
+
             return;
         }
         $instances = $counterLookup->fetchRequiredMetricInstances($vCenterUuid);
         if (empty($instances)) {
             $this->logger->notice('Got no instances to fetch, nothing to do');
+
             return;
         }
         $spec = PerformanceQuerySpecHelper::prepareQuerySpec(
@@ -191,6 +223,7 @@ protected function fetchPerf(
         );
         if ($this->influxDbWriter === null) {
             $this->logger->notice('No more InfluxDB writer available, nothing to do');
+
             return;
         }
 
@@ -214,7 +247,12 @@ protected function fetchPerf(
         });
     }
 
-    protected function sync($count = null)
+    /**
+     * @param ?int $count
+     *
+     * @return void
+     */
+    protected function sync(?int $count = null): void
     {
         $db = $this->vCenter->getConnection()->getDbAdapter();
         $uuid = Uuid::fromBytes($this->vCenter->getUuid());
@@ -244,7 +282,10 @@ protected function sync($count = null)
         $this->fetchPerf($db, $uuid, $set, $counterLookup, $count);
     }
 
-    protected function scheduleTasks()
+    /**
+     * @return void
+     */
+    protected function scheduleTasks(): void
     {
         $this->timers[] = $this->loop->addPeriodicTimer(120, function () {
             $this->loadWriterConfig()->then(function () {
@@ -259,17 +300,26 @@ protected function scheduleTasks()
         });
     }
 
-    protected function syncCounterInfo()
+    /**
+     * @return PromiseInterface
+     */
+    protected function syncCounterInfo(): PromiseInterface
     {
         return $this->api->getServiceInstance()->then(function (ServiceContent $content) {
             return $this->api->fetchSingleObject($content->perfManager);
         })->then(function ($result) {
             $this->storeCounterInfo($result);
+
             return resolve(null);
         });
     }
 
-    protected function storeCounterInfo($result)
+    /**
+     * @param mixed $result
+     *
+     * @return void
+     */
+    protected function storeCounterInfo(mixed $result): void
     {
         $store = new PerfCounterInfoSyncStore(
             $this->vCenter->getConnection()->getDbAdapter(),
diff --git a/library/Vspheredb/Daemon/RemoteApi.php b/library/Vspheredb/Daemon/RemoteApi.php
index 4f1883dd..fc57b908 100644
--- a/library/Vspheredb/Daemon/RemoteApi.php
+++ b/library/Vspheredb/Daemon/RemoteApi.php
@@ -14,14 +14,15 @@
 use gipfl\Protocol\NetString\StreamWrapper;
 use gipfl\Socket\UnixSocketInspection;
 use gipfl\Socket\UnixSocketPeer;
-use Icinga\Module\Vspheredb\Daemon\RpcNamespace\RpcNamespaceDbProxy;
-use Icinga\Module\Vspheredb\Daemon\RpcNamespace\RpcNamespaceProcess;
 use Icinga\Module\Vspheredb\Daemon\RpcNamespace\RpcNamespaceCurl;
+use Icinga\Module\Vspheredb\Daemon\RpcNamespace\RpcNamespaceDbProxy;
 use Icinga\Module\Vspheredb\Daemon\RpcNamespace\RpcNamespaceInfluxDb;
 use Icinga\Module\Vspheredb\Daemon\RpcNamespace\RpcNamespaceLogger;
+use Icinga\Module\Vspheredb\Daemon\RpcNamespace\RpcNamespaceProcess;
 use Icinga\Module\Vspheredb\Daemon\RpcNamespace\RpcNamespaceSystem;
 use Icinga\Module\Vspheredb\Daemon\RpcNamespace\RpcNamespaceVsphere;
 use Icinga\Module\Vspheredb\Polling\ApiConnectionHandler;
+use InvalidArgumentException;
 use Psr\Log\LoggerInterface;
 use React\EventLoop\LoopInterface;
 use React\Socket\ConnectionInterface;
@@ -33,24 +34,24 @@ class RemoteApi implements EventEmitterInterface
 {
     use EventEmitterTrait;
 
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
-    /** @var ControlSocket */
-    protected $controlSocket;
+    protected ?ControlSocket $controlSocket = null;
 
-    /** @var ApiConnectionHandler */
-    protected $apiConnectionHandler;
+    protected ApiConnectionHandler $apiConnectionHandler;
 
-    /** @var CurlAsync */
-    protected $curl;
+    protected CurlAsync $curl;
 
-    /** @var RpcNamespaceDbProxy */
-    protected $rpcNamespaceRpcProxy;
+    protected RpcNamespaceDbProxy $rpcNamespaceRpcProxy;
 
+    /**
+     * @param ApiConnectionHandler $apiConnectionHandler
+     * @param CurlAsync $curl
+     * @param LoopInterface $loop
+     * @param LoggerInterface $logger
+     */
     public function __construct(
         ApiConnectionHandler $apiConnectionHandler,
         CurlAsync $curl,
@@ -64,21 +65,37 @@ public function __construct(
         $this->rpcNamespaceRpcProxy = new RpcNamespaceDbProxy('db.');
     }
 
-    public function run($socketPath, LoopInterface $loop)
+    /**
+     * @param string $socketPath
+     * @param LoopInterface $loop
+     *
+     * @return void
+     */
+    public function run(string $socketPath, LoopInterface $loop): void
     {
         $this->loop = $loop;
         $this->initializeControlSocket($socketPath);
     }
 
-    public function setDbProcessRunner(?DbProcessRunner $dbProcessRunner)
+    /**
+     * @param ?DbProcessRunner $dbProcessRunner
+     *
+     * @return void
+     */
+    public function setDbProcessRunner(?DbProcessRunner $dbProcessRunner): void
     {
         $this->rpcNamespaceRpcProxy->setDbProcessRunner($dbProcessRunner);
     }
 
-    protected function initializeControlSocket($path)
+    /**
+     * @param string $path
+     *
+     * @return void
+     */
+    protected function initializeControlSocket(string $path): void
     {
         if (empty($path)) {
-            throw new \InvalidArgumentException('Control socket path expected, got none');
+            throw new InvalidArgumentException('Control socket path expected, got none');
         }
         $this->logger->info("[socket] launching control socket in $path");
         $socket = new ControlSocket($path);
@@ -87,7 +104,12 @@ protected function initializeControlSocket($path)
         $this->controlSocket = $socket;
     }
 
-    protected function isAllowed(UnixSocketPeer $peer)
+    /**
+     * @param UnixSocketPeer $peer
+     *
+     * @return bool
+     */
+    protected function isAllowed(UnixSocketPeer $peer): bool
     {
         if ($peer->getUid() === 0) {
             return true;
@@ -105,7 +127,12 @@ protected function isAllowed(UnixSocketPeer $peer)
         return in_array($myGid, array_map('intval', explode(' ', shell_exec("id -G $uid"))));
     }
 
-    protected function addSocketEventHandlers(ControlSocket $socket)
+    /**
+     * @param ControlSocket $socket
+     *
+     * @return void
+     */
+    protected function addSocketEventHandlers(ControlSocket $socket): void
     {
         $socket->on('connection', function (ConnectionInterface $connection) {
             $jsonRpc = new JsonRpcConnection(new StreamWrapper($connection));
diff --git a/library/Vspheredb/Daemon/RemoteClient.php b/library/Vspheredb/Daemon/RemoteClient.php
index 33b77077..2b3ad8f8 100644
--- a/library/Vspheredb/Daemon/RemoteClient.php
+++ b/library/Vspheredb/Daemon/RemoteClient.php
@@ -5,6 +5,7 @@
 use gipfl\Protocol\JsonRpc\JsonRpcConnection;
 use gipfl\Protocol\NetString\StreamWrapper;
 use React\EventLoop\LoopInterface;
+use React\Promise\PromiseInterface;
 use React\Socket\ConnectionInterface;
 use React\Socket\UnixConnector;
 
@@ -12,50 +13,66 @@
 
 class RemoteClient
 {
-    protected $path;
+    protected string $path;
 
-    /** @var JsonRpcConnection */
-    protected $connection;
+    protected ?JsonRpcConnection $connection = null;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
-    protected $pendingConnection;
+    protected ?PromiseInterface $pendingConnection = null;
 
-    public function __construct($path, LoopInterface $loop)
+    /**
+     * @param string $path
+     * @param LoopInterface $loop
+     */
+    public function __construct(string $path, LoopInterface $loop)
     {
         $this->path = $path;
         $this->loop = $loop;
     }
 
-    public function request($method, $params = null)
+    /**
+     * @param string $method
+     * @param ?array $params
+     *
+     * @return PromiseInterface
+     */
+    public function request(string $method, ?array $params = null): PromiseInterface
     {
         return $this->connection()->then(function (JsonRpcConnection $connection) use ($method, $params) {
             return $connection->request($method, $params);
         });
     }
 
-    public function notify($method, $params = null)
+    /**
+     * @param string $method
+     * @param ?array $params
+     *
+     * @return PromiseInterface
+     */
+    public function notify(string $method, ?array $params = null): PromiseInterface
     {
         return $this->connection()->then(function (JsonRpcConnection $connection) use ($method, $params) {
             $connection->notification($method, $params);
         });
     }
 
-    protected function connection()
+    /**
+     * @return PromiseInterface
+     */
+    protected function connection(): PromiseInterface
     {
         if ($this->connection === null) {
-            if ($this->pendingConnection === null) {
-                return $this->connect();
-            } else {
-                return $this->pendingConnection;
-            }
-        } else {
-            return resolve($this->connection);
+            return $this->pendingConnection ?? $this->connect();
         }
+
+        return resolve($this->connection);
     }
 
-    protected function connect()
+    /**
+     * @return PromiseInterface
+     */
+    protected function connect(): PromiseInterface
     {
         $connector = new UnixConnector($this->loop);
         $connected = function (ConnectionInterface $connection) {
diff --git a/library/Vspheredb/Daemon/RpcNamespace/DbRunner.php b/library/Vspheredb/Daemon/RpcNamespace/DbRunner.php
index 53be1ce9..1f6c78ec 100644
--- a/library/Vspheredb/Daemon/RpcNamespace/DbRunner.php
+++ b/library/Vspheredb/Daemon/RpcNamespace/DbRunner.php
@@ -5,6 +5,7 @@
 use Exception;
 use gipfl\Cli\Process;
 use Icinga\Data\ConfigObject;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Application\MemoryLimit;
 use Icinga\Module\Vspheredb\Daemon\DbCleanup;
 use Icinga\Module\Vspheredb\Db;
@@ -20,6 +21,8 @@
 use React\Promise\Deferred;
 use React\Promise\PromiseInterface;
 use RuntimeException;
+use Throwable;
+use Zend_Db_Adapter_Abstract;
 
 use function React\Promise\reject;
 use function React\Promise\resolve;
@@ -29,27 +32,27 @@
  */
 class DbRunner
 {
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    /** @var Db */
-    protected $connection;
+    protected ?Db $connection = null;
 
-    protected $db;
+    protected ?Zend_Db_Adapter_Abstract $db = null;
 
-    /** @var ?DbCleanup */
-    protected $runningVcenterDeletion = null;
+    protected ?VCenterCleanup $runningVcenterDeletion = null;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
-    protected $vCenters = [];
+    protected array $vCenters = [];
 
     /**
      * @var array vCenterId -> [ SyncStoreClassName => SyncStore ]
      */
-    protected $vCenterSyncStores = [];
+    protected array $vCenterSyncStores = [];
 
+    /**
+     * @param LoggerInterface $logger
+     * @param LoopInterface $loop
+     */
     public function __construct(LoggerInterface $logger, LoopInterface $loop)
     {
         MemoryLimit::raiseTo('1024M');
@@ -68,7 +71,7 @@ public function __construct(LoggerInterface $logger, LoopInterface $loop)
             if ($this->connection) {
                 try {
                     $this->refreshMonitoringRuleProblemsRequest();
-                } catch (\Throwable $e) {
+                } catch (Throwable $e) {
                     $this->logger->error($e->getMessage());
                 }
             }
@@ -77,10 +80,12 @@ public function __construct(LoggerInterface $logger, LoopInterface $loop)
 
     /**
      * @param object $config
+     *
      * @return PromiseInterface
+     *
      * @throws Exception
      */
-    public function setDbConfigRequest($config)
+    public function setDbConfigRequest(object $config): PromiseInterface
     {
         try {
             $this->vCenters = [];
@@ -111,7 +116,10 @@ public function setDbConfigRequest($config)
         }
     }
 
-    protected function setProcessReadyTitle()
+    /**
+     * @return void
+     */
+    protected function setProcessReadyTitle(): void
     {
         Process::setTitle('Icinga::vSphereDB::DB::connected');
     }
@@ -119,25 +127,27 @@ protected function setProcessReadyTitle()
     /**
      * @return bool
      */
-    public function runDbCleanupRequest()
+    public function runDbCleanupRequest(): bool
     {
         $this->requireCleanup()->runForStartup();
+
         return true;
     }
 
     /**
      * @return bool
      */
-    public function clearDbConfigRequest()
+    public function clearDbConfigRequest(): bool
     {
         $this->disconnect();
+
         return true;
     }
 
     /**
      * @return bool
      */
-    public function hasPendingMigrationsRequest()
+    public function hasPendingMigrationsRequest(): bool
     {
         if ($this->connection === null) {
             throw new RuntimeException('Unable to determine migration status, have no DB connection');
@@ -167,10 +177,12 @@ public function setCustomFieldsMapRequest(int $vCenterId, array $map): bool
 
     /**
      * @param int $vCenterId
+     *
      * @return int
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @throws NotFoundError
      */
-    public function getLastEventTimeStampRequest($vCenterId)
+    public function getLastEventTimeStampRequest(int $vCenterId): int
     {
         return VmEventHistorySyncStore::selectLast(
             $this->db,
@@ -185,17 +197,23 @@ public function getLastEventTimeStampRequest($vCenterId)
      * @param string $taskLabel
      * @param string $storeClass
      * @param string $objectClass
+     *
      * @return SyncStats
      */
-    public function processSyncTaskResultRequest($vCenterId, $result, $taskLabel, $storeClass, $objectClass)
-    {
+    public function processSyncTaskResultRequest(
+        int $vCenterId,
+        array $result,
+        string $taskLabel,
+        string $storeClass,
+        string $objectClass
+    ): SyncStats {
         Process::setTitle('Icinga::vSphereDB::DB::Storing ' . $taskLabel);
 
         $stats = new SyncStats($taskLabel);
         try {
             $this->requireSyncStoreForVCenterInstance($vCenterId, $storeClass)
                 ->store($result, $objectClass, $stats);
-        } catch (\Throwable $e) {
+        } catch (Throwable $e) {
             $this->logger->error(sprintf(
                 'Task %s failed. %s: %s (%d)',
                 $taskLabel,
@@ -209,15 +227,20 @@ public function processSyncTaskResultRequest($vCenterId, $result, $taskLabel, $s
         return $stats;
     }
 
-    public function refreshMonitoringRuleProblemsRequest()
+    /**
+     * @return bool
+     */
+    public function refreshMonitoringRuleProblemsRequest(): bool
     {
         if ($this->connection === null) {
             $this->logger->warning('Not refreshing Rule problems, DB is not ready');
+
             return false;
         }
 
         if (Db::migrationsForDb($this->connection)->hasPendingMigrations()) {
             $this->logger->warning('Not refreshing Rule problems, DB is not ready');
+
             return false;
         }
 
@@ -229,26 +252,26 @@ public function refreshMonitoringRuleProblemsRequest()
             $this->logger->debug(sprintf('Refreshing Monitoring Rule problems took %.2Fs', $duration));
 
             return true;
-        } catch (\Throwable $e) {
+        } catch (Throwable $e) {
             $this->logger->error('Refreshing Rule Problems failed: ' . $e->getMessage());
+
             return false;
         }
     }
 
     /**
      * @param int $vCenterId
+     *
      * @return bool
      */
-    public function deleteVcenterRequest($vCenterId)
+    public function deleteVcenterRequest(int $vCenterId): bool
     {
         $this->logger->notice('Got db.deleteVcenter for id=' . $vCenterId);
         if ($this->connection === null) {
             throw new RuntimeException('Unable to remove vCenter, have no DB connection');
         }
         if ($this->runningVcenterDeletion !== null) {
-            throw new RuntimeException(
-                'Unable to remove vCenter, a cleanup is in progress'
-            );
+            throw new RuntimeException('Unable to remove vCenter, a cleanup is in progress');
         }
 
         Process::setTitle('Icinga::vSphereDB::DB::deleteVcenter ' . $vCenterId);
@@ -269,7 +292,8 @@ public function deleteVcenterRequest($vCenterId)
      * @param string $class
      *
      * @return SyncStore
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @throws NotFoundError
      */
     protected function requireSyncStoreForVCenterInstance(int $vCenterId, string $class): SyncStore
     {
@@ -292,7 +316,8 @@ protected function requireSyncStoreForVCenterInstance(int $vCenterId, string $cl
      * @param int $id
      *
      * @return VCenter
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @throws NotFoundError
      */
     protected function requireVCenter(int $id): VCenter
     {
@@ -303,12 +328,17 @@ protected function requireVCenter(int $id): VCenter
         return $this->vCenters[$id];
     }
 
-    protected function connect($config)
+    /**
+     * @param object $config
+     *
+     * @return void
+     */
+    protected function connect(object $config): void
     {
         $this->logger->debug('Connecting to DB');
         try {
             $this->disconnect();
-        } catch (Exception $e) {
+        } catch (Exception) {
             // Ignore disconnection errors
         }
         $this->connection = new Db(new ConfigObject((array) $config));
@@ -316,7 +346,10 @@ protected function connect($config)
         $this->db->getConnection();
     }
 
-    protected function disconnect()
+    /**
+     * @return void
+     */
+    protected function disconnect(): void
     {
         if ($this->connection) {
             $this->connection->getDbAdapter()->closeConnection();
@@ -325,17 +358,21 @@ protected function disconnect()
         }
     }
 
-    protected function requireCleanup()
+    /**
+     * @return DbCleanup
+     */
+    protected function requireCleanup(): DbCleanup
     {
         if ($this->connection === null) {
             throw new RuntimeException('Cannot run DB cleanup w/o DB connection');
         }
         $c = new DbCleanup($this->connection->getDbAdapter(), $this->logger);
         Process::setTitle('Icinga::vSphereDB::DB::cleanup');
+
         return $c;
     }
 
-    protected function applyMigrations()
+    protected function applyMigrations(): PromiseInterface
     {
         try {
             $migrations = Db::migrationsForDb($this->connection);
diff --git a/library/Vspheredb/Daemon/RpcNamespace/LogProxy.php b/library/Vspheredb/Daemon/RpcNamespace/LogProxy.php
index c29088af..05ee5edb 100644
--- a/library/Vspheredb/Daemon/RpcNamespace/LogProxy.php
+++ b/library/Vspheredb/Daemon/RpcNamespace/LogProxy.php
@@ -6,17 +6,24 @@
 
 class LogProxy
 {
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    protected $prefix;
+    protected string $prefix = '';
 
+    /**
+     * @param LoggerInterface $logger
+     */
     public function __construct(LoggerInterface $logger)
     {
         $this->logger = $logger;
     }
 
-    public function setPrefix($prefix)
+    /**
+     * @param string $prefix
+     *
+     * @return $this
+     */
+    public function setPrefix(string $prefix): static
     {
         $this->prefix = $prefix;
 
@@ -27,8 +34,10 @@ public function setPrefix($prefix)
      * @param string $level
      * @param string $message
      * @param array $context
+     *
+     * @return void
      */
-    public function logNotification($level, $message, $context = [])
+    public function logNotification(string $level, string $message, array $context = []): void
     {
         $this->logger->log($level, $this->prefix . $message, $context);
     }
diff --git a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceCurl.php b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceCurl.php
index 8a324abf..30df6fe9 100644
--- a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceCurl.php
+++ b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceCurl.php
@@ -6,21 +6,21 @@
 
 class RpcNamespaceCurl
 {
-    /** @var CurlAsync */
-    protected $curl;
+    protected CurlAsync $curl;
 
+    /**
+     * @param CurlAsync $curl
+     */
     public function __construct(CurlAsync $curl)
     {
         $this->curl = $curl;
     }
 
-    public function getPendingConnectionsRequest()
+    /**
+     * @return array
+     */
+    public function getPendingConnectionsRequest(): array
     {
-        $handles = [];
-        foreach ($this->curl->getPendingCurlHandles() as $idx => $curl) {
-            $handles[$idx] = curl_getinfo($curl);
-        }
-
-        return $handles;
+        return array_map(fn ($curl) => curl_getinfo($curl), $this->curl->getPendingCurlHandles());
     }
 }
diff --git a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceDbProxy.php b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceDbProxy.php
index 2d63b7e8..5abe53dc 100644
--- a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceDbProxy.php
+++ b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceDbProxy.php
@@ -3,35 +3,49 @@
 namespace Icinga\Module\Vspheredb\Daemon\RpcNamespace;
 
 use Icinga\Module\Vspheredb\Daemon\DbProcessRunner;
+use React\Promise\PromiseInterface;
+use RuntimeException;
 
 class RpcNamespaceDbProxy
 {
-    /** @var ?DbProcessRunner */
-    protected $runner;
+    protected ?DbProcessRunner $runner = null;
 
-    /** @var string */
-    protected $prefix;
+    protected string $prefix;
 
+    /**
+     * @param string $prefix
+     */
     public function __construct(string $prefix)
     {
         $this->prefix = $prefix;
     }
 
-    public function setDbProcessRunner(?DbProcessRunner $runner)
+    /**
+     * @param ?DbProcessRunner $runner
+     *
+     * @return void
+     */
+    public function setDbProcessRunner(?DbProcessRunner $runner): void
     {
         $this->runner = $runner;
     }
 
-    public function __call($method, $params)
+    /**
+     * @param string $method
+     * @param array $params
+     *
+     * @return PromiseInterface
+     */
+    public function __call(string $method, array $params)
     {
-        if (preg_match('/Request$/', $method)) {
+        if (str_ends_with($method, 'Request')) {
             if ($this->runner === null) {
-                throw new \RuntimeException('DB runner is not ready');
+                throw new RuntimeException('DB runner is not ready');
             }
 
             return $this->runner->request($this->prefix . substr($method, 0, -7), $params);
         }
 
-        throw new \RuntimeException('Got no such method: ' . $method);
+        throw new RuntimeException('Got no such method: ' . $method);
     }
 }
diff --git a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceInfluxDb.php b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceInfluxDb.php
index 9a95186a..c1121b04 100644
--- a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceInfluxDb.php
+++ b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceInfluxDb.php
@@ -9,20 +9,23 @@
 use gipfl\InfluxDb\InfluxDbConnectionV2;
 use Psr\Log\LoggerInterface;
 use React\EventLoop\LoopInterface;
+use React\Promise\PromiseInterface;
 
 use function React\Promise\resolve;
 
 class RpcNamespaceInfluxDb
 {
-    /**
-     * @var LoopInterface
-     */
-    protected $loop;
+    protected LoopInterface $loop;
 
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    protected $curl;
+    protected CurlAsync $curl;
 
+    /**
+     * @param CurlAsync $curl
+     * @param LoopInterface $loop
+     * @param LoggerInterface $logger
+     */
     public function __construct(CurlAsync $curl, LoopInterface $loop, LoggerInterface $logger)
     {
         $this->curl = $curl;
@@ -32,8 +35,10 @@ public function __construct(CurlAsync $curl, LoopInterface $loop, LoggerInterfac
 
     /**
      * @param string $baseUrl Base URL
+     *
+     * @return PromiseInterface
      */
-    public function discoverVersionRequest($baseUrl)
+    public function discoverVersionRequest(string $baseUrl): PromiseInterface
     {
         return $this->connect($baseUrl)->then(function ($connection) {
             return $connection->getVersion();
@@ -42,12 +47,18 @@ public function discoverVersionRequest($baseUrl)
 
     /**
      * @param string $baseUrl Base URL
-     * @param string $apiVersion v1/v2
-     * @param string $username username / organization
-     * @param string $password password / token
+     * @param ?string $apiVersion v1/v2
+     * @param ?string $username username / organization
+     * @param ?string $password password / token
+     *
+     * @return PromiseInterface
      */
-    public function testConnectionRequest($baseUrl, $apiVersion = null, $username = null, $password = null)
-    {
+    public function testConnectionRequest(
+        string $baseUrl,
+        ?string $apiVersion = null,
+        ?string $username = null,
+        ?string $password = null
+    ): PromiseInterface {
         return $this->listDatabasesRequest($baseUrl, $apiVersion, $username, $password)->then(function () {
             return true;
         });
@@ -55,12 +66,18 @@ public function testConnectionRequest($baseUrl, $apiVersion = null, $username =
 
     /**
      * @param string $baseUrl Base URL
-     * @param string $apiVersion v1/v2
-     * @param string $username username / organization
-     * @param string $password password / token
+     * @param ?string $apiVersion v1/v2
+     * @param ?string $username username / organization
+     * @param ?string $password password / token
+     *
+     * @return PromiseInterface
      */
-    public function listDatabasesRequest($baseUrl, $apiVersion = null, $username = null, $password = null)
-    {
+    public function listDatabasesRequest(
+        string $baseUrl,
+        ?string $apiVersion = null,
+        ?string $username = null,
+        ?string $password = null
+    ): PromiseInterface {
         return $this->connect($baseUrl, $apiVersion, $username, $password)->then(function ($connection) {
             /** @var InfluxDbConnectionV1|InfluxDbConnectionV2 $connection */
             return $connection->listDatabases();
@@ -73,25 +90,42 @@ public function listDatabasesRequest($baseUrl, $apiVersion = null, $username = n
      * @param string $apiVersion v1/v2
      * @param string $username username / organization
      * @param string $password password / token
+     *
+     * @return PromiseInterface
      */
-    public function createDatabaseRequest($dbName, $baseUrl, $apiVersion, $username, $password)
-    {
+    public function createDatabaseRequest(
+        string $dbName,
+        string $baseUrl,
+        string $apiVersion,
+        string $username,
+        string $password
+    ): PromiseInterface {
         return $this->connect($baseUrl, $apiVersion, $username, $password)->then(function ($connection) use ($dbName) {
             /** @var InfluxDbConnection $connection */
             $this->logger->info("CREATING $dbName");
+
             return $connection->createDatabase($dbName);
         });
     }
 
-    protected function connect($baseUrl, $apiVersion = null, $username = null, $password = null)
-    {
-        switch ($apiVersion) {
-            case 'v1':
-                return resolve(new InfluxDbConnectionV1($this->curl, $baseUrl, $username, $password));
-            case 'v2':
-                return resolve(new InfluxDbConnectionV2($this->curl, $baseUrl, $username, $password));
-        }
-
-        return InfluxDbConnectionFactory::create($this->curl, $baseUrl, $username, $password);
+    /**
+     * @param string $baseUrl
+     * @param ?string $apiVersion
+     * @param ?string $username
+     * @param ?string $password
+     *
+     * @return PromiseInterface
+     */
+    protected function connect(
+        string $baseUrl,
+        ?string $apiVersion = null,
+        ?string $username = null,
+        ?string $password = null
+    ): PromiseInterface {
+        return match ($apiVersion) {
+            'v1'    => resolve(new InfluxDbConnectionV1($this->curl, $baseUrl, $username, $password)),
+            'v2'    => resolve(new InfluxDbConnectionV2($this->curl, $baseUrl, $username, $password)),
+            default => InfluxDbConnectionFactory::create($this->curl, $baseUrl, $username, $password),
+        };
     }
 }
diff --git a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceLogger.php b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceLogger.php
index a4da4941..5ed2dc20 100644
--- a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceLogger.php
+++ b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceLogger.php
@@ -8,9 +8,11 @@
 
 class RpcNamespaceLogger
 {
-    /** @var Logger */
-    protected $logger;
+    protected Logger $logger;
 
+    /**
+     * @param Logger $logger
+     */
     public function __construct(Logger $logger)
     {
         $this->logger = $logger;
@@ -19,16 +21,17 @@ public function __construct(Logger $logger)
     /**
      * @return string
      */
-    public function getLogLevelRequest()
+    public function getLogLevelRequest(): string
     {
         return LogLevel::mapNumericToName($this->getCurrentNumericLogLevel());
     }
 
     /**
      * @param string $level
+     *
      * @return bool
      */
-    public function setLogLevelRequest($level)
+    public function setLogLevelRequest(string $level): bool
     {
         $formerLevel = $this->getCurrentNumericLogLevel();
         $numericLevel = LogLevel::mapNameToNumeric($level);
@@ -56,7 +59,10 @@ public function setLogLevelRequest($level)
         return true;
     }
 
-    protected function getCurrentNumericLogLevel()
+    /**
+     * @return int
+     */
+    protected function getCurrentNumericLogLevel(): int
     {
         $level = LogLevel::LEVEL_DEBUG;
         foreach ($this->logger->getFilters() as $filter) {
diff --git a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceProcess.php b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceProcess.php
index c9eb8920..e88f0e78 100644
--- a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceProcess.php
+++ b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceProcess.php
@@ -12,9 +12,11 @@ class RpcNamespaceProcess implements EventEmitterInterface
 
     public const ON_RESTART = 'restart';
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
+    /**
+     * @param LoopInterface $loop
+     */
     public function __construct(LoopInterface $loop)
     {
         $this->loop = $loop;
@@ -33,7 +35,7 @@ protected function prepareProcessInfo(Daemon $daemon)
 
         return (object) [
             'state'   => $this->daemon->getProcessState()->getInfo(),
-            'details' => (object) $details,
+            'details' => (object) $details
         ];
     }
     */
@@ -41,7 +43,7 @@ protected function prepareProcessInfo(Daemon $daemon)
     /**
      * @return bool
      */
-    public function restartRequest()
+    public function restartRequest(): bool
     {
         // Grant some time to ship the response
         $this->loop->addTimer(0.1, function () {
diff --git a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceSystem.php b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceSystem.php
index 2b1b0d64..a2639d14 100644
--- a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceSystem.php
+++ b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceSystem.php
@@ -10,7 +10,7 @@ class RpcNamespaceSystem
     /**
      * @return object
      */
-    public function cpuCountersRequest()
+    public function cpuCountersRequest(): object
     {
         return (object) Cpu::getCounters();
     }
@@ -18,7 +18,7 @@ public function cpuCountersRequest()
     /**
      * @return object
      */
-    public function interfaceCountersRequest()
+    public function interfaceCountersRequest(): object
     {
         return (object) Network::getInterfaceCounters();
     }
diff --git a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceVsphere.php b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceVsphere.php
index 576f0e49..f0b66c5d 100644
--- a/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceVsphere.php
+++ b/library/Vspheredb/Daemon/RpcNamespace/RpcNamespaceVsphere.php
@@ -8,9 +8,11 @@
 
 class RpcNamespaceVsphere
 {
-    /** @var ApiConnectionHandler */
-    protected $apiConnectionHandler;
+    protected ApiConnectionHandler $apiConnectionHandler;
 
+    /**
+     * @param ApiConnectionHandler $apiConnectionHandler
+     */
     public function __construct(ApiConnectionHandler $apiConnectionHandler)
     {
         $this->apiConnectionHandler = $apiConnectionHandler;
@@ -20,6 +22,7 @@ public function __construct(ApiConnectionHandler $apiConnectionHandler)
      * Hint: Full qualified reference is necessary for RPC type check
      *
      * @param \Icinga\Module\Vspheredb\Polling\ServerSet $servers
+     *
      * @return bool
      */
     public function setServersRequest(ServerSet $servers): bool
diff --git a/library/Vspheredb/Daemon/StateMachine.php b/library/Vspheredb/Daemon/StateMachine.php
index b023e1a0..2e06c0ee 100644
--- a/library/Vspheredb/Daemon/StateMachine.php
+++ b/library/Vspheredb/Daemon/StateMachine.php
@@ -6,16 +6,20 @@
 
 trait StateMachine
 {
-    /** @var string */
-    private $currentState;
+    private ?string $currentState = null;
 
     /** @var array [fromState][toState] = [callback, ...] */
-    private $allowedTransitions = [];
+    private array $allowedTransitions = [];
 
     /** @var array [state] = [callback, ...] */
-    private $onState = [];
+    private array $onState = [];
 
-    public function initializeStateMachine($initialState)
+    /**
+     * @param string $initialState
+     *
+     * @return void
+     */
+    public function initializeStateMachine(string $initialState): void
     {
         if ($this->currentState !== null) {
             throw new RuntimeException('StateMachine has already been initialized');
diff --git a/library/Vspheredb/Daemon/VsphereDbDaemon.php b/library/Vspheredb/Daemon/VsphereDbDaemon.php
index ab6c057f..9b3aa731 100644
--- a/library/Vspheredb/Daemon/VsphereDbDaemon.php
+++ b/library/Vspheredb/Daemon/VsphereDbDaemon.php
@@ -8,7 +8,6 @@
 use gipfl\Cli\Process;
 use gipfl\Curl\CurlAsync;
 use gipfl\LinuxHealth\Memory;
-use gipfl\Log\Logger;
 use gipfl\Log\PrefixLogger;
 use gipfl\ReactUtils\RetryUnless;
 use gipfl\SimpleDaemon\DaemonState;
@@ -37,8 +36,11 @@
 use Ramsey\Uuid\Uuid;
 use Ramsey\Uuid\UuidInterface;
 use React\EventLoop\LoopInterface;
+use React\Promise\PromiseInterface;
 use React\Stream\Util as StreamUtil;
 use RuntimeException;
+use Zend_Db_Adapter_Abstract;
+use Zend_Db_Adapter_Exception;
 
 use function React\Promise\resolve;
 
@@ -60,59 +62,52 @@ class VsphereDbDaemon implements DaemonTask, SystemdAwareTask, LoggerAwareInterf
     public const STATE_FAILED   = 'failed';
     public const STATE_IDLE     = 'idle';
 
-    /** @var LoopInterface */
-    private $loop;
+    private ?LoopInterface $loop = null;
 
-    /** @var array|null */
-    protected $dbConfig;
+    protected ?array $dbConfig = null;
 
-    /** @var Db */
-    protected $connection;
+    protected ?Db $connection = null;
 
-    /** @var object */
-    protected $processInfo;
+    protected ?object $processInfo = null;
 
-    protected $delayOnFailed = 5;
+    protected int $delayOnFailed = 5;
 
-    /** @var NotifySystemD|boolean */
-    protected $systemd;
+    protected ?NotifySystemD $systemd = null;
 
-    /** @var DbLogger */
-    protected $dbLogger;
+    protected ?DbLogger $dbLogger = null;
 
-    /** @var RemoteApi */
-    protected $remoteApi;
+    protected ?RemoteApi $remoteApi = null;
 
-    /** @var @var RemoteClient */
-    protected $remoteClient;
+    protected ?RemoteClient $remoteClient = null;
 
-    /** @var CurlAsync */
-    protected $curl;
+    protected ?CurlAsync $curl = null;
 
-    /** @var ApiConnectionHandler */
-    protected $apiConnectionHandler;
+    protected ?ApiConnectionHandler $apiConnectionHandler = null;
 
-    /** @var DbProcessRunner */
-    protected $dbRunner;
+    protected ?DbProcessRunner $dbRunner = null;
 
-    /** @var DaemonState */
-    protected $daemonState;
+    protected ?DaemonState $daemonState = null;
 
-    protected $dbIsReady = false;
+    protected bool $dbIsReady = false;
 
     /** @var array [splhash(ApiConnection) => [ Task, ... ]] */
-    protected $runningTasks = [];
+    protected array $runningTasks = [];
 
-    /** @var ConfigWatch */
-    protected $configWatch;
+    protected ?ConfigWatch $configWatch = null;
 
-    protected $componentStates = [
+    /** @var array<string, string> */
+    protected array $componentStates = [
         self::COMPONENT_DB      => self::STATE_STOPPED,
         self::COMPONENT_LOCALDB => self::STATE_STOPPED,
-        self::COMPONENT_API     => self::STATE_STOPPED,
+        self::COMPONENT_API     => self::STATE_STOPPED
     ];
 
-    public function start(LoopInterface $loop)
+    /**
+     * @param LoopInterface $loop
+     *
+     * @return PromiseInterface
+     */
+    public function start(LoopInterface $loop): PromiseInterface
     {
         MemoryLimit::raiseTo('1024M');
         $this->loop = $loop;
@@ -125,20 +120,25 @@ public function start(LoopInterface $loop)
         $this->initializeDbProcess();
         $this->keepRefreshingServerConfig();
         $this->daemonState->setState(self::STATE_IDLE);
+
         return resolve(null);
     }
 
-    protected function initializeDaemonState()
+    /**
+     * @return DaemonState
+     */
+    protected function initializeDaemonState(): DaemonState
     {
         $daemonState = new DaemonState();
         $daemonState->setComponentStates($this->componentStates);
         $daemonState->on(DaemonState::ON_CHANGE, function ($processTitle, $statusSummary) use ($daemonState) {
-            if (strlen($statusSummary) === 0) {
-                Process::setTitle($processTitle);
-            } else {
-                Process::setTitle("$processTitle: $statusSummary");
+            $title = $processTitle;
+            if (strlen($statusSummary !== 0)) {
+                $title .= ": $statusSummary";
             }
 
+            Process::setTitle($title);
+
             if ($this->systemd && strlen($statusSummary) > 0) {
                 $this->systemd->setStatus($statusSummary);
             }
@@ -156,14 +156,24 @@ protected function initializeDaemonState()
         return $daemonState;
     }
 
-    protected function setInitialDaemonState()
+    /**
+     * @return void
+     */
+    protected function setInitialDaemonState(): void
     {
         $daemonState = $this->daemonState;
         $daemonState->setProcessTitle(self::PROCESS_NAME);
         $daemonState->setState(self::STATE_STARTING);
     }
 
-    protected function onComponentChange($component, $formerState, $currentState)
+    /**
+     * @param string $component
+     * @param string $formerState
+     * @param ?string $currentState
+     *
+     * @return void
+     */
+    protected function onComponentChange(string $component, string $formerState, ?string $currentState): void
     {
         $this->logger->debug("[$component] component changed from $formerState to $currentState");
         if ($this->daemonState->getComponentState($component) !== $currentState) {
@@ -238,9 +248,7 @@ protected function onComponentChange($component, $formerState, $currentState)
                     // Intentional fall-through:
                     // no break
                 case self::STATE_STOPPING:
-                    if ($this->apiConnectionHandler) {
-                        $this->apiConnectionHandler->stop();
-                    }
+                    $this->apiConnectionHandler?->stop();
                     $this->stopAllApiTasks();
                     $this->setApiState(self::STATE_STOPPED);
                     break;
@@ -248,7 +256,12 @@ protected function onComponentChange($component, $formerState, $currentState)
         }
     }
 
-    protected function stopComponent($component)
+    /**
+     * @param string $component
+     *
+     * @return void
+     */
+    protected function stopComponent(string $component): void
     {
         $state = $this->daemonState;
         if (! in_array($state->getComponentState($component), [self::STATE_STOPPED, self::STATE_STOPPING])) {
@@ -257,32 +270,56 @@ protected function stopComponent($component)
         }
     }
 
-    protected function setDbState($state)
+    /**
+     * @param string $state
+     *
+     * @return void
+     */
+    protected function setDbState(string $state): void
     {
         $this->daemonState->setComponentState(self::COMPONENT_DB, $state);
     }
 
-    protected function setLocalDbState($state)
+    /**
+     * @param string $state
+     *
+     * @return void
+     */
+    protected function setLocalDbState(string $state): void
     {
         $this->daemonState->setComponentState(self::COMPONENT_LOCALDB, $state);
     }
 
-    protected function setApiState($state)
+    /**
+     * @param string $state
+     *
+     * @return void
+     */
+    protected function setApiState(string $state): void
     {
         $this->daemonState->setComponentState(self::COMPONENT_API, $state);
     }
 
-    protected function getApiState()
+    /**
+     * @return ?string
+     */
+    protected function getApiState(): ?string
     {
         return $this->daemonState->getComponentState(self::COMPONENT_API);
     }
 
-    protected function getLocalDbState()
+    /**
+     * @return ?string
+     */
+    protected function getLocalDbState(): ?string
     {
         return $this->daemonState->getComponentState(self::COMPONENT_LOCALDB);
     }
 
-    protected function initializeDbProcess()
+    /**
+     * @return void
+     */
+    protected function initializeDbProcess(): void
     {
         $dbRunner = new DbProcessRunner($this->logger);
         $this->setDbState(self::STATE_STARTING);
@@ -295,27 +332,29 @@ protected function initializeDbProcess()
         });
         $dbRunner->run($this->loop)->then(function () use ($dbRunner) {
             $this->dbRunner = $dbRunner;
-            if ($this->remoteApi) {
-                $this->remoteApi->setDbProcessRunner($dbRunner);
-            }
+            $this->remoteApi?->setDbProcessRunner($dbRunner);
             $this->loop->futureTick(function () {
                 $this->setDbState(self::STATE_IDLE);
             });
         });
     }
 
-    protected function stopDbProcess()
+    /**
+     * @return void
+     */
+    protected function stopDbProcess(): void
     {
         if ($this->dbRunner) {
             $this->dbRunner->stop();
             $this->dbRunner = null;
-            if ($this->remoteApi) {
-                $this->remoteApi->setDbProcessRunner(null);
-            }
+            $this->remoteApi?->setDbProcessRunner(null);
         }
     }
 
-    protected function keepRefreshingServerConfig()
+    /**
+     * @return void
+     */
+    protected function keepRefreshingServerConfig(): void
     {
         $refresh = function () {
             if ($this->daemonState->getComponentState(self::COMPONENT_LOCALDB) === self::STATE_READY) {
@@ -326,20 +365,27 @@ protected function keepRefreshingServerConfig()
         $this->loop->futureTick($refresh);
     }
 
-    public function stop()
+    /**
+     * @return PromiseInterface
+     */
+    public function stop(): PromiseInterface
     {
         try {
             $this->daemonState->setState(self::STATE_STOPPING);
             $this->logger->notice('Stopping vSphereDbDaemon');
             $this->dbRunner->stop();
             $this->eventuallyDisconnectFromDb();
-        } catch (\Exception $e) {
+        } catch (Exception $e) {
             $this->logger->error('Failed to stop vSphereDbDaemon: ' . $e->getMessage());
         }
+
         return resolve(null);
     }
 
-    protected function detectProcessInfo()
+    /**
+     * @return void
+     */
+    protected function detectProcessInfo(): void
     {
         $this->processInfo = (object) [
             'instance_uuid' => Uuid::uuid4()->getBytes(),
@@ -347,11 +393,16 @@ protected function detectProcessInfo()
             'pid'           => posix_getpid(),
             'fqdn'          => Platform::getFqdn(),
             'username'      => Platform::getPhpUser(),
-            'php_version'   => Platform::getPhpVersion(),
+            'php_version'   => Platform::getPhpVersion()
         ];
     }
 
-    protected function initializeDbLogger(LoggerInterface $logger)
+    /**
+     * @param LoggerInterface $logger
+     *
+     * @return void
+     */
+    protected function initializeDbLogger(LoggerInterface $logger): void
     {
         // TODO: ProcessInfo!
         $this->dbLogger = new DbLogger(
@@ -366,7 +417,14 @@ protected function initializeDbLogger(LoggerInterface $logger)
         $logger->addWriter($this->dbLogger);
     }
 
-    protected function onNewConnectedServer(ServerInfo $server, AboutInfo $about, UuidInterface $uuid)
+    /**
+     * @param ServerInfo $server
+     * @param AboutInfo $about
+     * @param UuidInterface $uuid
+     *
+     * @return void
+     */
+    protected function onNewConnectedServer(ServerInfo $server, AboutInfo $about, UuidInterface $uuid): void
     {
         if (VCenter::exists($uuid->getBytes(), $this->connection)) {
             $this->logger->info(sprintf('Attached %s to an existing vCenter', $server->get('host')));
@@ -388,7 +446,12 @@ protected function onNewConnectedServer(ServerInfo $server, AboutInfo $about, Uu
         });
     }
 
-    protected function onApiConnection(ApiConnection $connection)
+    /**
+     * @param ApiConnection $connection
+     *
+     * @return void
+     */
+    protected function onApiConnection(ApiConnection $connection): void
     {
         $vCenter = VCenter::loadWithAutoIncId(
             $connection->getServerInfo()->getVCenterId(),
@@ -406,7 +469,7 @@ protected function onApiConnection(ApiConnection $connection)
             $restApi = new RestApi($serverInfo, $vCenter, $this->curl, $logger);
             $this->launchTasksForConnection($connection, [
                 new ObjectSync($vCenter, $connection->getApi(), $restApi, $this->dbRunner, $logger),
-                new PerfDataSync($vCenter, $connection->getApi(), $this->curl, $this->loop, $logger),
+                new PerfDataSync($vCenter, $connection->getApi(), $this->curl, $this->loop, $logger)
             ]);
         } catch (Exception $e) {
             $this->logger->error($e->getMessage());
@@ -416,8 +479,10 @@ protected function onApiConnection(ApiConnection $connection)
     /**
      * @param ApiConnection $connection
      * @param DaemonTask[] $tasks
+     *
+     * @return void
      */
-    protected function launchTasksForConnection(ApiConnection $connection, array $tasks)
+    protected function launchTasksForConnection(ApiConnection $connection, array $tasks): void
     {
         $idx = spl_object_hash($connection);
         $this->runningTasks[$idx] = $tasks;
@@ -427,7 +492,13 @@ protected function launchTasksForConnection(ApiConnection $connection, array $ta
         }
     }
 
-    protected function prepareApi(LoopInterface $loop, LoggerInterface $logger)
+    /**
+     * @param LoopInterface $loop
+     * @param LoggerInterface $logger
+     *
+     * @return void
+     */
+    protected function prepareApi(LoopInterface $loop, LoggerInterface $logger): void
     {
         $socketPath = Configuration::getSocketPath();
 
@@ -463,7 +534,12 @@ function (ServerInfo $server, AboutInfo $info, UuidInterface $uuid) {
         $this->remoteClient = new RemoteClient($socketPath, $loop);
     }
 
-    protected function stopApiTasksForConnection(ApiConnection $connection)
+    /**
+     * @param ApiConnection $connection
+     *
+     * @return void
+     */
+    protected function stopApiTasksForConnection(ApiConnection $connection): void
     {
         $this->stopApiTasksByConnectionIdx(spl_object_hash($connection));
     }
@@ -484,7 +560,10 @@ protected function stopApiTasksByConnectionIdx(string $idx): void
         }
     }
 
-    protected function stopAllApiTasks()
+    /**
+     * @return void
+     */
+    protected function stopAllApiTasks(): void
     {
         foreach ($this->runningTasks as $tasks) {
             foreach ($tasks as $task) {
@@ -495,7 +574,10 @@ protected function stopAllApiTasks()
         $this->runningTasks = [];
     }
 
-    protected function onConnected()
+    /**
+     * @return void
+     */
+    protected function onConnected(): void
     {
         $fail = function (Exception $e) {
             $this->logger->error($e->getMessage());
@@ -521,16 +603,23 @@ protected function onConnected()
             ->then($fail);
     }
 
-    protected function hasSchema()
+    /**
+     * @return bool
+     */
+    protected function hasSchema(): bool
     {
         return (Db::migrationsForDb($this->connection))->hasSchema();
     }
 
-    protected function sendDbConfigToRunner()
+    /**
+     * @return PromiseInterface
+     */
+    protected function sendDbConfigToRunner(): PromiseInterface
     {
         $this->logger->notice('[db] sending DB config to child process');
         if (! $this->daemonState->getComponentState(self::COMPONENT_DB) === self::STATE_READY) {
             $this->logger->warning('[db] DB runner is NOT ready, not sending config');
+
             return resolve(null);
         }
         if ($this->dbConfig === null) {
@@ -540,14 +629,15 @@ protected function sendDbConfigToRunner()
                 $this->logger->error('[db] clearing DB config failed: ' . $e->getMessage());
                 $this->setDbState(self::STATE_FAILED);
             });
-        } else {
-            return $this->dbRunner->request('db.setDbConfig', [
-                'config' => $this->dbConfig
-            ]);
         }
+
+        return $this->dbRunner->request('db.setDbConfig', ['config' => $this->dbConfig]);
     }
 
-    protected function reconnectToDb()
+    /**
+     * @return void
+     */
+    protected function reconnectToDb(): void
     {
         if ($this->connection !== null) {
             $this->eventuallyDisconnectFromDb();
@@ -566,7 +656,12 @@ protected function reconnectToDb()
         });
     }
 
-    protected function connectToDb($config)
+    /**
+     * @param $config
+     *
+     * @return Db
+     */
+    protected function connectToDb($config): Db
     {
         $connection = new Db(new ConfigObject($config));
         $connection->getDbAdapter()->getConnection();
@@ -578,7 +673,12 @@ protected function connectToDb($config)
         return $connection;
     }
 
-    protected function eventuallyDisconnectFromDb($refresh = true)
+    /**
+     * @param bool $refresh
+     *
+     * @return void
+     */
+    protected function eventuallyDisconnectFromDb(bool $refresh = true): void
     {
         if ($this->connection !== null) {
             try {
@@ -603,7 +703,10 @@ protected function eventuallyDisconnectFromDb($refresh = true)
         }
     }
 
-    protected function runConfigWatch()
+    /**
+     * @return void
+     */
+    protected function runConfigWatch(): void
     {
         if ($this->configWatch) {
             return;
@@ -616,23 +719,26 @@ protected function runConfigWatch()
         $config->run($this->loop);
     }
 
-    protected function onDbConfig($config)
+    /**
+     * @param ?array $config
+     *
+     * @return void
+     */
+    protected function onDbConfig(?array $config): void
     {
         if ($config === null) {
             $this->setDbState('config error');
             if ($this->dbConfig === null) {
                 $this->logger->error('[configwatch] Got no valid DB configuration');
+
                 return;
-            } else {
-                $this->logger->error('[configwatch] There is no longer a valid DB configuration');
-                $this->dbConfig = $config;
-                $sent = $this->sendDbConfigToRunner();
             }
+            $this->logger->error('[configwatch] There is no longer a valid DB configuration');
         } else {
             $this->logger->notice('[configwatch] DB configuration loaded');
-            $this->dbConfig = $config;
-            $sent = $this->sendDbConfigToRunner();
         }
+        $this->dbConfig = $config;
+        $sent = $this->sendDbConfigToRunner();
         $sent->then(function () {
             $this->stopComponent(self::COMPONENT_API);
             $this->setDbState(self::STATE_READY);
@@ -642,15 +748,21 @@ protected function onDbConfig($config)
         });
     }
 
-    protected function stopConfigWatch()
+    /**
+     * @return void
+     */
+    protected function stopConfigWatch(): void
     {
-        if ($this->configWatch) {
-            $this->configWatch->stop();
-            $this->configWatch = null;
-        }
+        $this->configWatch?->stop();
+        $this->configWatch = null;
     }
 
-    protected function refreshMyState($disconnectOnError = true)
+    /**
+     * @param bool $disconnectOnError
+     *
+     * @return void
+     */
+    protected function refreshMyState(bool $disconnectOnError = true): void
     {
         if ($this->connection === null) {
             return;
@@ -659,10 +771,10 @@ protected function refreshMyState($disconnectOnError = true)
             $db = $this->connection->getDbAdapter();
             $updated = $db->update('vspheredb_daemon', [
                 'ts_last_refresh' => Util::currentTimestamp(),
-                'process_info' => json_encode($this->getProcessInfo()),
+                'process_info' => json_encode($this->getProcessInfo())
             ], $db->quoteInto('instance_uuid = ?', DbUtil::quoteBinaryCompat($this->processInfo->instance_uuid, $db)));
 
-            if (!$updated) {
+            if (! $updated) {
                 $this->insertMyState($db);
             }
         } catch (Exception $e) {
@@ -674,33 +786,41 @@ protected function refreshMyState($disconnectOnError = true)
     }
 
     /**
-     * @param \Zend_Db_Adapter_Abstract $db
-     * @throws \Zend_Db_Adapter_Exception
+     * @param Zend_Db_Adapter_Abstract $db
+     *
+     * @return void
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
-    protected function insertMyState(\Zend_Db_Adapter_Abstract $db)
+    protected function insertMyState(Zend_Db_Adapter_Abstract $db): void
     {
         $db->insert('vspheredb_daemon', [
             'instance_uuid' => $this->processInfo->instance_uuid,
             'ts_last_refresh' => Util::currentTimestamp(),
-            'process_info'    => json_encode($this->getProcessInfo()),
+            'process_info'    => json_encode($this->getProcessInfo())
         ] + (array) $this->processInfo);
     }
 
-    protected function getProcessInfo()
+    /**
+     * @return object
+     */
+    protected function getProcessInfo(): object
     {
         global $argv;
         /** @var int $pid */
         $pid = $this->processInfo->pid;
-        $info = (object) [$pid => (object) [
+
+        return (object) [$pid => (object) [
             'command' => implode(' ', $argv),
             'running' => true,
             'memory'  => Memory::getUsageForPid($pid)
         ]];
-
-        return $info;
     }
 
-    protected function refreshConfiguredServers()
+    /**
+     * @return void
+     */
+    protected function refreshConfiguredServers(): void
     {
         if ($this->connection === null) {
             return;
@@ -717,7 +837,12 @@ protected function refreshConfiguredServers()
         }
     }
 
-    public function setSystemd(NotifySystemD $systemd)
+    /**
+     * @param NotifySystemD $systemd
+     *
+     * @return void
+     */
+    public function setSystemd(NotifySystemD $systemd): void
     {
         $this->systemd = $systemd;
     }
diff --git a/library/Vspheredb/Data/Anonymizer.php b/library/Vspheredb/Data/Anonymizer.php
index 86e0f792..9f46d15d 100644
--- a/library/Vspheredb/Data/Anonymizer.php
+++ b/library/Vspheredb/Data/Anonymizer.php
@@ -7,9 +7,13 @@
 
 class Anonymizer
 {
-    /** @var ?AnonymizerHook */
-    protected static $instance = null;
+    protected static AnonymizerHook|false|null $instance = null;
 
+    /**
+     * @param ?string $string
+     *
+     * @return ?string
+     */
     public static function anonymizeString(?string $string): ?string
     {
         if ($instance = self::instance()) {
@@ -19,6 +23,11 @@ public static function anonymizeString(?string $string): ?string
         return $string;
     }
 
+    /**
+     * @param ?string $string
+     *
+     * @return ?string
+     */
     public static function shuffleString(?string $string): ?string
     {
         if ($instance = self::instance()) {
@@ -28,16 +37,20 @@ public static function shuffleString(?string $string): ?string
         return $string;
     }
 
+    /**
+     * @return ?AnonymizerHook
+     */
     protected static function instance(): ?AnonymizerHook
     {
         if (self::$instance === null) {
             $instance = Hook::first('vspheredb/Anonymizer');
             if ($instance === null) {
                 self::$instance = false;
+
                 return null;
-            } else {
-                self::$instance = $instance;
             }
+
+            self::$instance = $instance;
         } elseif (self::$instance === false) {
             return null;
         }
diff --git a/library/Vspheredb/Db.php b/library/Vspheredb/Db.php
index d102a4d1..e9de608f 100644
--- a/library/Vspheredb/Db.php
+++ b/library/Vspheredb/Db.php
@@ -10,14 +10,12 @@
 
 class Db extends DbConnection
 {
-    public static function newConfiguredInstance()
+    public static function newConfiguredInstance(): Db
     {
-        return static::fromResourceName(
-            Config::module('vspheredb')->get('db', 'resource')
-        );
+        return static::fromResourceName(Config::module('vspheredb')->get('db', 'resource'));
     }
 
-    public static function migrationsForDb(Db $connection)
+    public static function migrationsForDb(Db $connection): Migrations
     {
         $db = $connection->getDbAdapter();
         assert($db instanceof Zend_Db_Adapter_Pdo_Abstract);
diff --git a/library/Vspheredb/Db/BulkPathLookup.php b/library/Vspheredb/Db/BulkPathLookup.php
index 1debfd75..c72c50c7 100644
--- a/library/Vspheredb/Db/BulkPathLookup.php
+++ b/library/Vspheredb/Db/BulkPathLookup.php
@@ -8,20 +8,27 @@
 
 class BulkPathLookup
 {
-    /** @var Db */
-    protected $db;
+    protected Db $db;
 
-    protected $nodes;
+    protected ?array $nodes = null;
 
-    /** @var ?array */
-    protected $vCenterFilterUuids;
+    protected ?array $vCenterFilterUuids;
 
+    /**
+     * @param Db $db
+     * @param ?array $vCenterUuids
+     */
     public function __construct(Db $db, ?array $vCenterUuids = null)
     {
         $this->db = $db;
         $this->vCenterFilterUuids = $vCenterUuids;
     }
 
+    /**
+     * @param ?string $objectParent
+     *
+     * @return array
+     */
     public function getParents(?string $objectParent): array
     {
         if ($this->nodes === null) {
@@ -41,6 +48,9 @@ public function getParents(?string $objectParent): array
         return array_reverse($path, true);
     }
 
+    /**
+     * @return array
+     */
     protected function fetchAllParents(): array
     {
         $db = $this->db->getDbAdapter();
@@ -55,6 +65,7 @@ protected function fetchAllParents(): array
         foreach ($db->fetchAll($query) as $row) {
             $result[$row->uuid] = $row;
         }
+
         return $result;
     }
 }
diff --git a/library/Vspheredb/Db/CheckRelatedLookup.php b/library/Vspheredb/Db/CheckRelatedLookup.php
index 0544b4be..ea7ca17b 100644
--- a/library/Vspheredb/Db/CheckRelatedLookup.php
+++ b/library/Vspheredb/Db/CheckRelatedLookup.php
@@ -8,18 +8,26 @@
 use Icinga\Module\Vspheredb\DbObject\Datastore;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
+use InvalidArgumentException;
 
 class CheckRelatedLookup
 {
-    /** @var Db */
-    protected $connection;
+    protected Db $connection;
 
+    /**
+     * @param Db $connection
+     */
     public function __construct(Db $connection)
     {
         $this->connection = $connection;
     }
 
-    public function listNonGreenObjects($type)
+    /**
+     * @param string $type
+     *
+     * @return array
+     */
+    public function listNonGreenObjects(string $type): array
     {
         $db = $this->connection->getDbAdapter();
         $select = $db->select()
@@ -45,10 +53,12 @@ public function listNonGreenObjects($type)
     /**
      * @param string $type
      * @param array $filter
+     *
      * @return BaseDbObject
+     *
      * @throws NotFoundError
      */
-    public function findOneBy($type, $filter)
+    public function findOneBy(string $type, array $filter): BaseDbObject
     {
         $result = $this->findBy($type, $filter);
 
@@ -70,9 +80,10 @@ public function findOneBy($type, $filter)
     /**
      * @param string $type
      * @param array $filter
+     *
      * @return array
      */
-    private function findBy($type, $filter)
+    private function findBy(string $type, array $filter): array
     {
         $db = $this->connection->getDbAdapter();
         $class = static::getClassForType($type);
@@ -89,7 +100,7 @@ private function findBy($type, $filter)
             }
             if ($value === null) {
                 $select->where($key);
-            } elseif (strpos($key, '?') === false) {
+            } elseif (! str_contains($key, '?')) {
                 $select->where("$key = ?", $value);
             } else {
                 $select->where($key, $value);
@@ -102,19 +113,17 @@ private function findBy($type, $filter)
     /**
      * @param string $type
      *
-     * @return string
+     * @return class-string
+     *
+     * @throws InvalidArgumentException
      */
     private static function getClassForType(string $type): string
     {
-        $classes = [
+        return match ($type) {
             'VirtualMachine' => VirtualMachine::class,
             'HostSystem'     => HostSystem::class,
             'Datastore'      => Datastore::class,
-        ];
-        if (! isset($classes[$type])) {
-            throw new \InvalidArgumentException("'$type' is an unknown type");
-        }
-
-        return $classes[$type];
+            default          => throw new InvalidArgumentException("'$type' is an unknown type")
+        };
     }
 }
diff --git a/library/Vspheredb/Db/DbConnection.php b/library/Vspheredb/Db/DbConnection.php
index 3f726cf2..3216ff22 100644
--- a/library/Vspheredb/Db/DbConnection.php
+++ b/library/Vspheredb/Db/DbConnection.php
@@ -12,17 +12,28 @@
 
 class DbConnection extends IcingaDbConnection
 {
-    public function isMysql()
+    /**
+     * @return bool
+     */
+    public function isMysql(): bool
     {
         return $this->getDbType() === 'mysql';
     }
 
-    public function isPgsql()
+    /**
+     * @return bool
+     */
+    public function isPgsql(): bool
     {
         return $this->getDbType() === 'pgsql';
     }
 
-    public function quoteBinary($binary)
+    /**
+     * @param string|array $binary
+     *
+     * @return Zend_Db_Expr|array|string
+     */
+    public function quoteBinary(string|array $binary): Zend_Db_Expr|array|string
     {
         if ($binary === '') {
             return '';
@@ -39,7 +50,12 @@ public function quoteBinary($binary)
         return new Zend_Db_Expr('0x' . bin2hex($binary));
     }
 
-    public function hasPgExtension($name)
+    /**
+     * @param string $name
+     *
+     * @return bool
+     */
+    public function hasPgExtension(string $name): bool
     {
         $db = $this->getDbAdapter();
         $query = $db->select()->from(
@@ -50,7 +66,14 @@ public function hasPgExtension($name)
         return (int) $db->fetchOne($query) === 1;
     }
 
-    public static function pgBinEscape($binary)
+    /**
+     * @param $binary
+     *
+     * @return Zend_Db_Expr
+     *
+     * @throws RuntimeException
+     */
+    public static function pgBinEscape($binary): Zend_Db_Expr
     {
         if ($binary instanceof Zend_Db_Expr) {
             throw new RuntimeException('Trying to escape binary twice');
diff --git a/library/Vspheredb/Db/DbObject.php b/library/Vspheredb/Db/DbObject.php
index ee07c33d..c5876f3f 100644
--- a/library/Vspheredb/Db/DbObject.php
+++ b/library/Vspheredb/Db/DbObject.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Db;
 
+use Exception;
 use gipfl\Json\JsonString;
 use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Db;
@@ -10,70 +11,58 @@
 use LogicException;
 use Ramsey\Uuid\Uuid;
 use RuntimeException;
+use stdClass;
 use Zend_Db_Adapter_Abstract;
+use Zend_Db_Adapter_Exception;
 use Zend_Db_Exception;
+use Zend_Db_Expr;
+use Zend_Db_Select;
 
 /**
  * Cloned from Director. Should sooner or later be replaced by something modern
  */
 abstract class DbObject
 {
-    /** @var DbConnection $connection */
-    protected $connection;
+    protected ?DbConnection $connection = null;
 
-    /** @var string Table name. MUST be set when extending this class */
-    protected $table;
+    /** @var ?string Table name. MUST be set when extending this class */
+    protected ?string $table = null;
 
-    /** @var Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected ?Zend_Db_Adapter_Abstract $db = null;
 
     /**
      * Default columns. MUST be set when extending this class. Each table
      * column MUST be defined with a default value. Default value may be null.
      *
-     * @var array
+     * @var ?array
      */
-    protected $defaultProperties;
+    protected ?array $defaultProperties = null;
 
-    /**
-     * Properties as loaded from db
-     */
-    protected $loadedProperties;
+    /** @var ?array Properties as loaded from db */
+    protected ?array $loadedProperties = null;
 
-    /**
-     * Whether at least one property has been modified
-     */
-    protected $hasBeenModified = false;
+    /** @var bool Whether at least one property has been modified */
+    protected bool $hasBeenModified = false;
 
-    /**
-     * Whether this object has been loaded from db
-     */
-    protected $loadedFromDb = false;
+    /** @var bool Whether this object has been loaded from db */
+    protected bool $loadedFromDb = false;
 
-    /**
-     * Object properties
-     */
-    protected $properties = [];
+    /** @var array Object properties */
+    protected array $properties = [];
 
-    /**
-     * Property names that have been modified since object creation
-     */
-    protected $modifiedProperties = [];
+    /** @var array Property names that have been modified since object creation */
+    protected array $modifiedProperties = [];
 
-    /**
-     * Unique key name, could be primary
-     */
-    protected $keyName;
+    /** @var string|string[]|null Unique key name, could be primary */
+    protected string|array|null $keyName = null;
 
-    /**
-     * Set this to an eventual autoincrementing column. May equal $keyName
-     */
-    protected $autoincKeyName;
+    /** @var ?string Set this to an eventual autoincrementing column. May equal $keyName */
+    protected ?string $autoincKeyName = null;
 
     /** @var bool forbid updates to autoinc values */
-    protected $protectAutoinc = true;
+    protected bool $protectAutoinc = true;
 
-    protected $binaryProperties = [];
+    protected array $binaryProperties = [];
 
     /**
      * Constructor is not accessible and should not be overridden
@@ -92,7 +81,10 @@ protected function __construct()
         $this->beforeInit();
     }
 
-    public function getTableName()
+    /**
+     * @return ?string
+     */
+    public function getTableName(): ?string
     {
         return $this->table;
     }
@@ -108,9 +100,9 @@ public function getTableName()
      * the object. Please note that the method is public and allows to check
      * object consistence at any time.
      *
-     * @return boolean  Whether this object is valid
+     * @return boolean Whether this object is valid
      */
-    public function validate()
+    public function validate(): bool
     {
         return true;
     }
@@ -121,7 +113,7 @@ public function validate()
      *
      * @return void
      */
-    protected function beforeInit()
+    protected function beforeInit(): void
     {
     }
 
@@ -131,7 +123,7 @@ protected function beforeInit()
      *
      * @return void
      */
-    protected function onLoadFromDb()
+    protected function onLoadFromDb(): void
     {
     }
 
@@ -142,67 +134,66 @@ protected function onLoadFromDb()
      *
      * @return void
      */
-    protected function beforeStore()
+    protected function beforeStore(): void
     {
     }
 
     /**
-     * Wird ausgeführt, nachdem ein Objekt erfolgreich gespeichert worden ist
+     * Will be executed after an object has been stored successfully
      *
      * @return void
      */
-    protected function onStore()
+    protected function onStore(): void
     {
     }
 
     /**
-     * Wird ausgeführt, nachdem ein Objekt erfolgreich der Datenbank hinzu-
-     * gefügt worden ist
+     * Will be executed after an object has successfully been inserted into the
+     * database
      *
      * @return void
      */
-    protected function onInsert()
+    protected function onInsert(): void
     {
     }
 
     /**
-     * Wird ausgeführt, nachdem bestehendes Objekt erfolgreich der Datenbank
-     * geändert worden ist
+     * Will be executed after an existing object has been successfully updated
      *
      * @return void
      */
-    protected function onUpdate()
+    protected function onUpdate(): void
     {
     }
 
     /**
-     * Wird ausgeführt, bevor ein Objekt gelöscht wird. Die Operation wird
-     * aber auf jeden Fall durchgeführt, außer man wirft eine Exception
+     * Will be executed before an object will be deleted. The operation will
+     * definitely be executed, except an exception is thrown.
      *
      * @return void
      */
-    protected function beforeDelete()
+    protected function beforeDelete(): void
     {
     }
 
     /**
-     * Wird ausgeführt, nachdem bestehendes Objekt erfolgreich aud der
-     * Datenbank gelöscht worden ist
+     * Will be executed after an existing object has been successfully deleted
+     * from the database
      *
      * @return void
      */
-    protected function onDelete()
+    protected function onDelete(): void
     {
     }
 
     /**
      * Set database connection
      *
-     * @param DbConnection $connection Database connection
+     * @param ?DbConnection $connection Database connection
      *
-     * @return self
+     * @return $this
      */
-    public function setConnection(DbConnection $connection)
+    public function setConnection(?DbConnection $connection): static
     {
         $this->connection = $connection;
         $this->db = $connection->getDbAdapter();
@@ -217,10 +208,10 @@ public function setConnection(DbConnection $connection)
      *
      * @return mixed
      */
-    public function get($property)
+    public function get(string $property): mixed
     {
         $func = 'get' . ucfirst($property);
-        if (substr($func, -2) === '[]') {
+        if (str_ends_with($func, '[]')) {
             $func = substr($func, 0, -2);
         }
         // TODO: id check avoids collision with getId. Rethink this.
@@ -229,6 +220,7 @@ public function get($property)
         }
 
         $this->assertPropertyExists($property);
+
         return $this->properties[$property];
     }
 
@@ -244,7 +236,14 @@ public function getProperty(string $key): mixed
         return $this->properties[$key];
     }
 
-    protected function assertPropertyExists($key)
+    /**
+     * @param string $key
+     *
+     * @return $this
+     *
+     * @throws InvalidArgumentException
+     */
+    protected function assertPropertyExists(string $key): static
     {
         if (! array_key_exists($key, $this->properties)) {
             throw new InvalidArgumentException(sprintf(
@@ -256,7 +255,12 @@ protected function assertPropertyExists($key)
         return $this;
     }
 
-    public function hasProperty($key)
+    /**
+     * @param string $key
+     *
+     * @return bool
+     */
+    public function hasProperty(string $key): bool
     {
         if (array_key_exists($key, $this->properties)) {
             return true;
@@ -265,12 +269,13 @@ public function hasProperty($key)
             return false;
         }
         $func = 'get' . ucfirst($key);
-        if (substr($func, -2) === '[]') {
+        if (str_ends_with($func, '[]')) {
             $func = substr($func, 0, -2);
         }
         if (method_exists($this, $func)) {
             return true;
         }
+
         return false;
     }
 
@@ -278,13 +283,12 @@ public function hasProperty($key)
      * Generic setter
      *
      * @param string $key
-     * @param mixed  $value
+     * @param mixed $value
      *
-     * @return self
+     * @return $this|null
      */
-    public function set($key, $value)
+    public function set(string $key, mixed $value): ?static
     {
-        $key = (string) $key;
         if ($value === '') {
             $value = null;
         }
@@ -303,7 +307,7 @@ public function set($key, $value)
         }
 
         $func = 'set' . ucfirst($key);
-        if (substr($func, -2) === '[]') {
+        if (str_ends_with($func, '[]')) {
             $func = substr($func, 0, -2);
         }
 
@@ -318,10 +322,7 @@ public function set($key, $value)
             ));
         }
 
-        if (
-            (is_numeric($value) || is_string($value))
-            && (string) $value === (string) $this->get($key)
-        ) {
+        if ((is_numeric($value) || is_string($value)) && (string) $value === (string) $this->get($key)) {
             return $this;
         }
 
@@ -334,11 +335,11 @@ public function set($key, $value)
 
     /**
      * @param string $key
-     * @param $value
+     * @param mixed $value
      *
      * @return $this
      */
-    protected function reallySet(string $key, $value): static
+    protected function reallySet(string $key, mixed $value): static
     {
         if ($value === $this->properties[$key]) {
             return $this;
@@ -354,11 +355,11 @@ protected function reallySet(string $key, $value): static
     /**
      * Magic getter
      *
-     * @param mixed $key
+     * @param string $key
      *
      * @return mixed
      */
-    public function __get($key)
+    public function __get(string $key): mixed
     {
         return $this->get($key);
     }
@@ -366,12 +367,12 @@ public function __get($key)
     /**
      * Magic setter
      *
-     * @param  string  $key  Key
-     * @param  mixed   $val  Value
+     * @param string $key Key
+     * @param  mixed $val Value
      *
      * @return void
      */
-    public function __set($key, $val)
+    public function __set(string $key, mixed $val): void
     {
         $this->set($key, $val);
     }
@@ -379,10 +380,11 @@ public function __set($key, $val)
     /**
      * Magic isset check
      *
-     * @param  string $key
-     * @return boolean
+     * @param string $key
+     *
+     * @return bool
      */
-    public function __isset($key)
+    public function __isset(string $key): bool
     {
         return array_key_exists($key, $this->properties);
     }
@@ -405,17 +407,12 @@ public function __unset(string $key): void
     /**
      * Runs set() for every key/value pair of the given Array
      *
-     * @param  array $props  Array of properties
-     * @return self
+     * @param array $props Array of properties
+     *
+     * @return $this
      */
-    public function setProperties($props)
+    public function setProperties(array $props): static
     {
-        if (! is_array($props)) {
-            throw new InvalidArgumentException(sprintf(
-                'Array required, got %s',
-                gettype($props)
-            ));
-        }
         foreach ($props as $key => $value) {
             $this->set($key, $value);
         }
@@ -427,7 +424,7 @@ public function setProperties($props)
      *
      * @return array
      */
-    public function getProperties()
+    public function getProperties(): array
     {
         //return $this->properties;
         $res = [];
@@ -438,12 +435,18 @@ public function getProperties()
         return $res;
     }
 
-    protected function getPropertiesForDb()
+    /**
+     * @return ?array
+     */
+    protected function getPropertiesForDb(): ?array
     {
         return $this->properties;
     }
 
-    public function listProperties()
+    /**
+     * @return array
+     */
+    public function listProperties(): array
     {
         return array_keys($this->properties);
     }
@@ -453,20 +456,17 @@ public function listProperties()
      *
      * @return array
      */
-    public function getModifiedProperties()
+    public function getModifiedProperties(): array
     {
         $props = [];
         foreach (array_keys($this->modifiedProperties) as $key) {
-            if ($key === $this->autoincKeyName) {
-                if ($this->protectAutoinc) {
-                    continue;
-                } elseif ($this->properties[$key] === null) {
-                    continue;
-                }
+            if ($key === $this->autoincKeyName && ($this->protectAutoinc || $this->properties[$key] === null)) {
+                continue;
             }
 
             $props[$key] = $this->properties[$key];
         }
+
         return $props;
     }
 
@@ -475,7 +475,7 @@ public function getModifiedProperties()
      *
      * @return array
      */
-    public function listModifiedProperties()
+    public function listModifiedProperties(): array
     {
         return array_keys($this->modifiedProperties);
     }
@@ -485,7 +485,7 @@ public function listModifiedProperties()
      *
      * @return bool
      */
-    public function hasBeenModified()
+    public function hasBeenModified(): bool
     {
         return $this->hasBeenModified;
     }
@@ -493,10 +493,11 @@ public function hasBeenModified()
     /**
      * Whether the given property has been modified
      *
-     * @param  string   $key Property name
-     * @return boolean
+     * @param string $key Property name
+     *
+     * @return bool
      */
-    protected function hasModifiedProperty($key)
+    protected function hasModifiedProperty(string $key): bool
     {
         return array_key_exists($key, $this->modifiedProperties);
     }
@@ -521,7 +522,10 @@ public function getAutoincKeyName(): ?string
         return $this->autoincKeyName;
     }
 
-    public function getKeyParams()
+    /**
+     * @return array
+     */
+    public function getKeyParams(): array
     {
         $params = [];
         $key = $this->getKeyName();
@@ -542,11 +546,11 @@ public function getKeyParams()
      *
      * // TODO: may conflict with ->id
      *
-     * @throws InvalidArgumentException When key can not be calculated
+     * @return string|array|null
      *
-     * @return string|array
+     * @throws InvalidArgumentException When key can not be calculated
      */
-    public function getId()
+    public function getId(): array|string|null
     {
         $keyName = $this->getKeyName();
         if (is_array($keyName)) {
@@ -563,29 +567,33 @@ public function getId()
             }
 
             return $id;
-        } else {
-            if (isset($this->properties[$keyName])) {
-                return $this->properties[$keyName];
-            }
         }
+        if (isset($this->properties[$keyName])) {
+            return $this->properties[$keyName];
+        }
+
         return null;
     }
 
     /**
      * Get the autoinc value if set
      *
-     * @return int
+     * @return ?int
      */
-    public function getAutoincId()
+    public function getAutoincId(): ?int
     {
         $autoincKeyName = $this->getAutoincKeyName();
         if ($autoincKeyName !== null && isset($this->properties[$autoincKeyName])) {
             return (int) $this->properties[$autoincKeyName];
         }
+
         return null;
     }
 
-    protected function forgetAutoincId()
+    /**
+     * @return $this
+     */
+    protected function forgetAutoincId(): static
     {
         $autoincKeyName = $this->getAutoincKeyName();
         if ($autoincKeyName !== null && isset($this->properties[$autoincKeyName])) {
@@ -596,51 +604,46 @@ protected function forgetAutoincId()
     }
 
     /**
-     * Liefert das benutzte Datenbank-Handle
+     * Returns the used database handle
      *
-     * @return Zend_Db_Adapter_Abstract
+     * @return ?Zend_Db_Adapter_Abstract
      */
-    public function getDb()
+    public function getDb(): ?Zend_Db_Adapter_Abstract
     {
         return $this->db;
     }
 
-    public function hasConnection()
+    public function hasConnection(): bool
     {
         return $this->connection !== null;
     }
 
-    public function getConnection()
+    /**
+     * @return ?DbConnection
+     */
+    public function getConnection(): ?DbConnection
     {
         return $this->connection;
     }
 
     /**
-     * Lädt einen Datensatz aus der Datenbank und setzt die entsprechenden
-     * Eigenschaften dieses Objekts
+     * Loads a record from the database and sets the corresponding properties
+     * on the object
+     *
+     * @return $this
      *
      * @throws NotFoundError
-     * @return self
      */
-    protected function loadFromDb()
+    protected function loadFromDb(): static
     {
         $select = $this->db->select()->from($this->table)->where($this->createWhere());
         $properties = $this->db->fetchRow($select);
 
         if (empty($properties)) {
             if (is_array($this->getKeyName())) {
-                throw new NotFoundError(
-                    'Failed to load %s for %s',
-                    $this->table,
-                    $this->createWhere()
-                );
-            } else {
-                throw new NotFoundError(
-                    'Failed to load %s "%s"',
-                    $this->table,
-                    $this->getLogId()
-                );
+                throw new NotFoundError('Failed to load %s for %s', $this->table, $this->createWhere());
             }
+            throw new NotFoundError('Failed to load %s "%s"', $this->table, $this->getLogId());
         }
 
         return $this->setDbProperties($properties);
@@ -649,16 +652,22 @@ protected function loadFromDb()
     /**
      * @param object $row
      * @param Db $db
-     * @return self
+     *
+     * @return static
      */
-    public static function fromDbRow($row, Db $db)
+    public static function fromDbRow(object $row, Db $db): static
     {
         return (new static())
             ->setConnection($db)
             ->setDbProperties($row);
     }
 
-    public function setDbProperties($properties)
+    /**
+     * @param array|stdClass $properties
+     *
+     * @return $this
+     */
+    public function setDbProperties(array|stdClass $properties): static
     {
         foreach ($properties as $key => $val) {
             if (! array_key_exists($key, $this->properties)) {
@@ -682,10 +691,14 @@ public function setDbProperties($properties)
         $this->hasBeenModified = false;
         $this->modifiedProperties = [];
         $this->onLoadFromDb();
+
         return $this;
     }
 
-    public function getOriginalProperties()
+    /**
+     * @return ?array
+     */
+    public function getOriginalProperties(): ?array
     {
         return $this->loadedProperties;
     }
@@ -693,7 +706,7 @@ public function getOriginalProperties()
     /**
      * @param string $key
      *
-     * @return mixed|null
+     * @return ?mixed
      */
     public function getOriginalProperty(string $key): mixed
     {
@@ -720,18 +733,22 @@ public function resetProperty(string $key): static
         return $this;
     }
 
-    public function hasBeenLoadedFromDb()
+    /**
+     * @return bool
+     */
+    public function hasBeenLoadedFromDb(): bool
     {
         return $this->loadedFromDb;
     }
 
     /**
-     * Ändert den entsprechenden Datensatz in der Datenbank
+     * Updates the corresponding record in the database
      *
-     * @return int  Anzahl der geänderten Zeilen
-     * @throws \Zend_Db_Adapter_Exception
+     * @return int|true Number of updated rows
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
-    protected function updateDb()
+    protected function updateDb(): int|true
     {
         $properties = $this->getModifiedProperties();
         if (empty($properties)) {
@@ -748,12 +765,13 @@ protected function updateDb()
     }
 
     /**
-     * Fügt der Datenbank-Tabelle einen entsprechenden Datensatz hinzu
+     * Inserts a record into the database table
+     *
+     * @return int Number of affected rows
      *
-     * @return int  Anzahl der betroffenen Zeilen
-     * @throws \Zend_Db_Adapter_Exception
+     * @throws Zend_Db_Adapter_Exception
      */
-    protected function insertIntoDb()
+    protected function insertIntoDb(): int
     {
         $properties = $this->getPropertiesForDb();
         $autoincKeyName = $this->getAutoincKeyName();
@@ -774,7 +792,12 @@ protected function insertIntoDb()
         return $this->db->insert($this->table, $properties);
     }
 
-    protected function isBinaryColumn($column)
+    /**
+     * @param string $column
+     *
+     * @return bool
+     */
+    protected function isBinaryColumn(string $column): bool
     {
         return in_array($column, $this->binaryProperties);
     }
@@ -782,11 +805,15 @@ protected function isBinaryColumn($column)
     /**
      * Store object to database
      *
-     * @param  DbConnection $db
-     * @return bool Whether storing succeeded
+     * @param ?DbConnection $db
+     *
+     * @return true Whether storing succeeded
+     *
+     * @throws InvalidArgumentException
+     * @throws RuntimeException
      * @throws DuplicateKeyException
      */
-    public function store(?DbConnection $db = null)
+    public function store(?DbConnection $db = null): true
     {
         if ($db !== null) {
             $this->setConnection($db);
@@ -810,15 +837,10 @@ public function store(?DbConnection $db = null)
 
         try {
             if ($this->hasBeenLoadedFromDb()) {
-                if ($this->updateDb() !== false) {
-                    $result = true;
+                if ($this->updateDb()) {
                     $this->onUpdate();
                 } else {
-                    throw new RuntimeException(sprintf(
-                        'FAILED storing %s "%s"',
-                        $table,
-                        $this->getLogId()
-                    ));
+                    throw new RuntimeException(sprintf('FAILED storing %s "%s"', $table, $this->getLogId()));
                 }
             } else {
                 $autoincKeyName = $this->getAutoincKeyName();
@@ -828,30 +850,19 @@ public function store(?DbConnection $db = null)
                     if ($autoId = $this->getAutoincId()) {
                         $logId .= sprintf(', %s=%s', $autoincKeyName, $autoId);
                     }
-                    throw new DuplicateKeyException(
-                        'Trying to recreate %s (%s)',
-                        $table,
-                        $logId
-                    );
+                    throw new DuplicateKeyException('Trying to recreate %s (%s)', $table, $logId);
                 }
 
                 if ($this->insertIntoDb()) {
                     if ($autoincKeyName && $this->getProperty($autoincKeyName) === null) {
-                        if ($this->connection->isPgsql()) {
-                            $this->properties[$autoincKeyName] = $this->db->lastInsertId($table, $autoincKeyName);
-                        } else {
-                            $this->properties[$autoincKeyName] = $this->db->lastInsertId();
-                        }
+                        $this->properties[$autoincKeyName] = $this->connection->isPgsql()
+                            ? $this->db->lastInsertId($table, $autoincKeyName)
+                            : $this->db->lastInsertId();
                     }
                     // $this->log(sprintf('New %s "%s" has been stored', $table, $id));
                     $this->onInsert();
-                    $result = true;
                 } else {
-                    throw new RuntimeException(sprintf(
-                        'FAILED to store new %s "%s"',
-                        $table,
-                        $this->getLogId()
-                    ));
+                    throw new RuntimeException(sprintf('FAILED to store new %s "%s"', $table, $this->getLogId()));
                 }
             }
         } catch (Zend_Db_Exception $e) {
@@ -870,15 +881,15 @@ public function store(?DbConnection $db = null)
         $this->onStore();
         $this->loadedFromDb = true;
 
-        return $result;
+        return true;
     }
 
     /**
      * Delete item from DB
      *
-     * @return int  Affected rows
+     * @return int Affected rows
      */
-    protected function deleteFromDb()
+    protected function deleteFromDb(): int
     {
         return $this->db->delete(
             $this->table,
@@ -890,9 +901,10 @@ protected function deleteFromDb()
      * @param string[]|string $key
      *
      * @return self
+     *
      * @throws InvalidArgumentException
      */
-    protected function setKey(array|string $key)
+    protected function setKey(array|string $key): static
     {
         $keyname = $this->getKeyName();
         if (is_array($keyname)) {
@@ -913,10 +925,14 @@ protected function setKey(array|string $key)
         } else {
             $this->set($keyname, $key);
         }
+
         return $this;
     }
 
-    protected function existsInDb()
+    /**
+     * @return bool
+     */
+    protected function existsInDb(): bool
     {
         $result = $this->db->fetchRow(
             $this->db->select()->from($this->table)->where($this->createWhere())
@@ -924,7 +940,10 @@ protected function existsInDb()
         return $result !== false;
     }
 
-    public function createWhere()
+    /**
+     * @return string
+     */
+    public function createWhere(): string
     {
         if ($id = $this->getAutoincId()) {
             if ($originalId = $this->getOriginalProperty($this->autoincKeyName)) {
@@ -946,31 +965,32 @@ public function createWhere()
             /** @var string $k */
             foreach ($key as $k) {
                 if ($this->hasBeenLoadedFromDb()) {
-                    if ($this->loadedProperties[$k] === null) {
-                        $where[] = sprintf('%s IS NULL', $k);
-                    } else {
-                        $where[] = $this->createQuotedWhere($k, $this->loadedProperties[$k]);
-                    }
+                    $where[] = $this->loadedProperties[$k] === null
+                        ? sprintf('%s IS NULL', $k)
+                        : $this->createQuotedWhere($k, $this->loadedProperties[$k]);
                 } else {
-                    if ($this->properties[$k] === null) {
-                        $where[] = sprintf('%s IS NULL', $k);
-                    } else {
-                        $where[] = $this->createQuotedWhere($k, $this->properties[$k]);
-                    }
+                    $where[] = $this->properties[$k] === null
+                        ? sprintf('%s IS NULL', $k)
+                        : $this->createQuotedWhere($k, $this->properties[$k]);
                 }
             }
 
             return implode(' AND ', $where);
-        } else {
-            if ($this->hasBeenLoadedFromDb()) {
-                return $this->createQuotedWhere($key, $this->loadedProperties[$key]);
-            } else {
-                return $this->createQuotedWhere($key, $this->properties[$key]);
-            }
         }
+
+        return $this->createQuotedWhere(
+            $key,
+            $this->hasBeenLoadedFromDb() ? $this->loadedProperties[$key] : $this->properties[$key]
+        );
     }
 
-    protected function createQuotedWhere($column, $value)
+    /**
+     * @param string $column
+     * @param mixed $value
+     *
+     * @return string
+     */
+    protected function createQuotedWhere(string $column, mixed $value): string
     {
         return $this->db->quoteInto(
             sprintf('%s = ?', $column),
@@ -978,16 +998,25 @@ protected function createQuotedWhere($column, $value)
         );
     }
 
-    protected function eventuallyQuoteBinary($value, $column)
+    /**
+     * @param mixed $value
+     * @param string $column
+     *
+     * @return array|mixed|string|Zend_Db_Expr
+     */
+    protected function eventuallyQuoteBinary(mixed $value, string $column): mixed
     {
         if ($this->isBinaryColumn($column)) {
             return $this->connection->quoteBinary($value);
-        } else {
-            return $value;
         }
+
+        return $value;
     }
 
-    protected function getLogId()
+    /**
+     * @return mixed|string
+     */
+    protected function getLogId(): mixed
     {
         if (is_array($this->keyName)) {
             $id = [];
@@ -999,7 +1028,7 @@ protected function getLogId()
             }
             try {
                 return JsonString::encode($id);
-            } catch (\Exception $e) {
+            } catch (Exception $e) {
                 return 'Key encoding failed: ' . $e->getMessage();
             }
         }
@@ -1009,12 +1038,14 @@ protected function getLogId()
 
     /**
      * @param string $name
+     *
+     * @return mixed|string
      */
-    protected function getReadableProperty(string $name)
+    protected function getReadableProperty(string $name): mixed
     {
         if (isset($this->properties[$name])) {
             $value = $this->properties[$name];
-            if (preg_match('/uuid$/', $name) && strlen($value) === 16) {
+            if (str_ends_with($name, 'uuid') && strlen($value) === 16) {
                 return Uuid::fromBytes($value)->toString();
             }
 
@@ -1024,7 +1055,10 @@ protected function getReadableProperty(string $name)
         return $this->defaultProperties[$name];
     }
 
-    public function delete()
+    /**
+     * @return true
+     */
+    public function delete(): true
     {
         $table = $this->table;
 
@@ -1054,10 +1088,14 @@ public function delete()
         // $this->log(sprintf('%s "%s" has been DELETED', $table, this->getLogId()));
         $this->onDelete();
         $this->loadedFromDb = false;
+
         return true;
     }
 
-    public function __clone()
+    /**
+     * @return void
+     */
+    public function __clone(): void
     {
         $this->onClone();
         $this->forgetAutoincId();
@@ -1065,17 +1103,20 @@ public function __clone()
         $this->hasBeenModified = true;
     }
 
-    protected function onClone()
+    /**
+     * @return void
+     */
+    protected function onClone(): void
     {
     }
 
     /**
      * @param array $properties
-     * @param DbConnection|null $connection
+     * @param ?DbConnection $connection
      *
      * @return static
      */
-    public static function create($properties = [], ?DbConnection $connection = null)
+    public static function create(array $properties = [], ?DbConnection $connection = null): static
     {
         $obj = new static();
         if ($connection !== null) {
@@ -1086,12 +1127,14 @@ public static function create($properties = [], ?DbConnection $connection = null
     }
 
     /**
-     * @param $id
-     * @param DbConnection $connection
+     * @param int|string $id
+     * @param ?DbConnection $connection
+     *
      * @return static
+     *
      * @throws NotFoundError
      */
-    public static function loadWithAutoIncId($id, DbConnection $connection)
+    public static function loadWithAutoIncId(int|string $id, ?DbConnection $connection): static
     {
         /* Need to cast to int, otherwise the id will be matched against
          * object_name, which may wreak havoc if an object has a
@@ -1110,12 +1153,14 @@ public static function loadWithAutoIncId($id, DbConnection $connection)
     }
 
     /**
-     * @param $id
+     * @param string $id
      * @param DbConnection $connection
+     *
      * @return static
+     *
      * @throws NotFoundError
      */
-    public static function load($id, DbConnection $connection)
+    public static function load(string $id, DbConnection $connection): static
     {
         $obj = new static();
         $obj->setConnection($connection)->setKey($id)->loadFromDb();
@@ -1125,13 +1170,16 @@ public static function load($id, DbConnection $connection)
 
     /**
      * @param DbConnection $connection
-     * @param \Zend_Db_Select $query
-     * @param string|null $keyColumn
+     * @param ?Zend_Db_Select $query
+     * @param ?string $keyColumn
      *
      * @return static[]
      */
-    public static function loadAll(DbConnection $connection, $query = null, $keyColumn = null)
-    {
+    public static function loadAll(
+        DbConnection $connection,
+        ?Zend_Db_Select $query = null,
+        ?string $keyColumn = null
+    ): array {
         $objects = [];
         $db = $connection->getDbAdapter();
 
@@ -1144,7 +1192,6 @@ public static function loadAll(DbConnection $connection, $query = null, $keyColu
         $rows = $db->fetchAll($select);
 
         foreach ($rows as $row) {
-            /** @var DbObject $obj */
             $obj = new static();
             $obj->setConnection($connection)->setDbProperties($row);
             if ($keyColumn === null) {
@@ -1168,12 +1215,14 @@ public static function loadAll(DbConnection $connection, $query = null, $keyColu
     /**
      * @param $id
      * @param DbConnection $connection
+     *
      * @return bool
      */
-    public static function exists($id, DbConnection $connection)
+    public static function exists($id, DbConnection $connection): bool
     {
         $obj = new static();
         $obj->setConnection($connection)->setKey($id);
+
         return $obj->existsInDb();
     }
 
diff --git a/library/Vspheredb/Db/DbUtil.php b/library/Vspheredb/Db/DbUtil.php
index adff3318..016b8179 100644
--- a/library/Vspheredb/Db/DbUtil.php
+++ b/library/Vspheredb/Db/DbUtil.php
@@ -16,7 +16,12 @@
 
 class DbUtil
 {
-    public static function binaryResult($value)
+    /**
+     * @param $value
+     *
+     * @return false|mixed|string
+     */
+    public static function binaryResult($value): mixed
     {
         if (is_resource($value)) {
             return stream_get_contents($value);
@@ -26,12 +31,15 @@ public static function binaryResult($value)
     }
 
     /**
-     * @param string|array $binary
+     * @param array|string|null $binary
      * @param Zend_Db_Adapter_Abstract $db
-     * @return Zend_Db_Expr|Zend_Db_Expr[]
+     *
+     * @return Zend_Db_Expr|Zend_Db_Expr[]|null
      */
-    public static function quoteBinaryLegacy($binary, $db)
-    {
+    public static function quoteBinaryLegacy(
+        array|string|null $binary,
+        Zend_Db_Adapter_Abstract $db
+    ): Zend_Db_Expr|array|null {
         if (is_array($binary)) {
             return static::quoteArray($binary, 'quoteBinaryLegacy', $db);
         }
@@ -48,11 +56,12 @@ public static function quoteBinaryLegacy($binary, $db)
     }
 
     /**
-     * @param string|array $binary
+     * @param array|string|null $binary
      * @param Adapter $db
-     * @return Expr|Expr[]
+     *
+     * @return Expr|Expr[]|null
      */
-    public static function quoteBinary($binary, $db)
+    public static function quoteBinary(array|string|null $binary, Adapter $db): Expr|array|null
     {
         if (is_array($binary)) {
             return static::quoteArray($binary, 'quoteBinary', $db);
@@ -70,12 +79,15 @@ public static function quoteBinary($binary, $db)
     }
 
     /**
-     * @param string|array $binary
-     * @param Adapter|Zend_Db_Adapter_Abstract $db
-     * @return Expr|Zend_Db_Expr|Expr[]|Zend_Db_Expr[]
+     * @param array|string|null $binary
+     * @param Zend_Db_Adapter_Abstract|Adapter $db
+     *
+     * @return Expr|Zend_Db_Expr|Expr[]|Zend_Db_Expr[]|null
      */
-    public static function quoteBinaryCompat($binary, $db)
-    {
+    public static function quoteBinaryCompat(
+        array|string|null $binary,
+        Zend_Db_Adapter_Abstract|Adapter $db
+    ): Zend_Db_Expr|Expr|array|null {
         if ($db instanceof Adapter) {
             return static::quoteBinary($binary, $db);
         }
@@ -83,7 +95,14 @@ public static function quoteBinaryCompat($binary, $db)
         return static::quoteBinaryLegacy($binary, $db);
     }
 
-    protected static function quoteArray($array, $method, $db)
+    /**
+     * @param array $array
+     * @param string $method
+     * @param Adapter|Zend_Db_Adapter_Abstract $db
+     *
+     * @return array
+     */
+    protected static function quoteArray(array $array, string $method, Adapter|Zend_Db_Adapter_Abstract $db): array
     {
         $result = [];
         foreach ($array as $bin) {
diff --git a/library/Vspheredb/Db/QueryHelper.php b/library/Vspheredb/Db/QueryHelper.php
index 29d55771..5424094e 100644
--- a/library/Vspheredb/Db/QueryHelper.php
+++ b/library/Vspheredb/Db/QueryHelper.php
@@ -3,11 +3,24 @@
 namespace Icinga\Module\Vspheredb\Db;
 
 use Zend_Db_Adapter_Abstract as ZfDb;
+use Zend_Db_Select;
 
 class QueryHelper
 {
-    public static function applyOptionalVCenterFilter(ZfDb $db, $query, string $column, ?array $vCenterFilterUuids)
-    {
+    /**
+     * @param ZfDb $db
+     * @param Zend_Db_Select $query
+     * @param string $column
+     * @param ?array $vCenterFilterUuids
+     *
+     * @return void
+     */
+    public static function applyOptionalVCenterFilter(
+        ZfDb $db,
+        Zend_Db_Select $query,
+        string $column,
+        ?array $vCenterFilterUuids
+    ): void {
         if ($vCenterFilterUuids === null) {
             return;
         }
diff --git a/library/Vspheredb/Db/TagLookup.php b/library/Vspheredb/Db/TagLookup.php
index 3dc30cb5..05f3fb12 100644
--- a/library/Vspheredb/Db/TagLookup.php
+++ b/library/Vspheredb/Db/TagLookup.php
@@ -10,18 +10,19 @@
 
 class TagLookup
 {
-    /** @var Db */
-    protected $db;
+    protected Db $db;
 
-    /** @var array */
-    protected $assignments;
+    protected array $assignments;
 
     /** @var TaggingTag[] */
-    protected $tags;
+    protected array $tags;
 
     /** @var TaggingCategory[] */
-    protected $categories;
+    protected array $categories;
 
+    /**
+     * @param Db $db
+     */
     public function __construct(Db $db)
     {
         $this->db = $db;
@@ -30,6 +31,11 @@ public function __construct(Db $db)
         $this->categories = TaggingCategory::loadAll($this->db, null, 'uuid');
     }
 
+    /**
+     * @param string $objectUuid
+     *
+     * @return stdClass
+     */
     public function getTags(string $objectUuid): stdClass
     {
         if (!isset($this->assignments[$objectUuid])) {
@@ -71,6 +77,9 @@ public function getTags(string $objectUuid): stdClass
         return (object) $result;
     }
 
+    /**
+     * @return array
+     */
     protected function fetchAllAssignments(): array
     {
         $db = $this->db->getDbAdapter();
diff --git a/library/Vspheredb/Db/VCenterCleanup.php b/library/Vspheredb/Db/VCenterCleanup.php
index 8137c181..9b2985a6 100644
--- a/library/Vspheredb/Db/VCenterCleanup.php
+++ b/library/Vspheredb/Db/VCenterCleanup.php
@@ -3,23 +3,35 @@
 namespace Icinga\Module\Vspheredb\Db;
 
 use Exception;
-use gipfl\ZfDb\Adapter\Adapter;
 use Icinga\Module\Vspheredb\Db;
 use InvalidArgumentException;
 use React\EventLoop\Loop;
 use React\Promise\Deferred;
 use React\Promise\PromiseInterface;
+use RuntimeException;
+use Throwable;
+use Zend_Db_Adapter_Abstract;
 
 class VCenterCleanup
 {
     protected Db $connection;
+
     protected int $vCenterId;
+
     protected array $scheduledQueries = [];
+
     protected string $vCenterUuid;
+
     protected ?Deferred $deferred = null;
-    /** @var \Zend_Db_Adapter_Abstract|Adapter */
-    protected $db;
 
+    protected Zend_Db_Adapter_Abstract $db;
+
+    /**
+     * @param Db $connection
+     * @param int $vCenterId
+     *
+     * @throws InvalidArgumentException
+     */
     public function __construct(Db $connection, int $vCenterId)
     {
         $this->connection = $connection;
@@ -33,6 +45,11 @@ public function __construct(Db $connection, int $vCenterId)
         $this->vCenterUuid = $uuid;
     }
 
+    /**
+     * @return PromiseInterface
+     *
+     * @throws RuntimeException
+     */
     public function run(): PromiseInterface
     {
         if ($this->deferred !== null) {
@@ -45,25 +62,27 @@ public function run(): PromiseInterface
         return $this->deferred->promise();
     }
 
+    /**
+     * @return void
+     */
     protected function tick(): void
     {
         $query = array_shift($this->scheduledQueries);
         if ($query === null) {
-            if ($this->deferred) {
-                // Should never be null, this is just a safety measure
-                $this->deferred->resolve(true);
-            }
+            // Should never be null, this is just a safety measure
+            $this->deferred?->resolve(true);
+
             return;
         }
 
         try {
             $this->db->query($query[0], $query[1]);
             Loop::futureTick(fn () => $this->tick());
-        } catch (\Throwable $e) {
+        } catch (Throwable $e) {
             $deferred = $this->deferred;
             $this->scheduledQueries = [];
             $this->deferred = null;
-            $deferred->reject(new \Exception(sprintf(
+            $deferred->reject(new Exception(sprintf(
                 "Query %s failed: %s",
                 $query[0],
                 $e->getMessage()
@@ -71,6 +90,9 @@ protected function tick(): void
         }
     }
 
+    /**
+     * @return void
+     */
     protected function scheduleQueries(): void
     {
         $uuid = $this->vCenterUuid;
@@ -158,7 +180,7 @@ protected function scheduleQueries(): void
             ['DELETE FROM object WHERE vcenter_uuid = ? ORDER BY level DESC;', [$uuid]],
             ['OPTIMIZE TABLE object', []],
             ['DELETE FROM vcenter WHERE id = ?;', [$this->vCenterId]],
-            ['OPTIMIZE TABLE vcenter', []],
+            ['OPTIMIZE TABLE vcenter', []]
         ];
     }
 }
diff --git a/library/Vspheredb/DbObject/BaseDbObject.php b/library/Vspheredb/DbObject/BaseDbObject.php
index 56642b3c..4af2dc31 100644
--- a/library/Vspheredb/DbObject/BaseDbObject.php
+++ b/library/Vspheredb/DbObject/BaseDbObject.php
@@ -3,82 +3,95 @@
 namespace Icinga\Module\Vspheredb\DbObject;
 
 use gipfl\Json\JsonSerialization;
-use Icinga\Module\Vspheredb\Db\DbObject as VspheredbDbObject;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Db;
+use Icinga\Module\Vspheredb\Db\DbObject as VspheredbDbObject;
 use Icinga\Module\Vspheredb\MappedClass\ElementDescription;
 use Icinga\Module\Vspheredb\Util;
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
+use InvalidArgumentException;
 use Ramsey\Uuid\Uuid;
+use ReturnTypeWillChange;
 
 abstract class BaseDbObject extends VspheredbDbObject implements JsonSerialization
 {
-    /** @var Db $connection Exists in parent, but IDEs need a better hint */
-    protected $connection;
+    protected string|array|null $keyName = 'id';
 
-    protected $keyName = 'id';
+    private ?ManagedObject $object = null;
 
-    /** @var ManagedObject */
-    private $object;
+    protected array $propertyMap = [];
 
-    protected $propertyMap = [];
+    protected array $objectReferences = [];
 
-    protected $objectReferences = [];
+    protected array $booleanProperties = [];
 
-    protected $booleanProperties = [];
-
-    protected $dateTimeProperties = [];
+    protected array $dateTimeProperties = [];
 
     /**
      * @param string $uuid
      * @param Db $connection
+     *
      * @return static
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @throws NotFoundError
      */
-    public static function loadWithUuid(string $uuid, Db $connection)
+    public static function loadWithUuid(string $uuid, Db $connection): static
     {
-        if (strlen($uuid) === 16) {
-            $uuid = Uuid::fromBytes($uuid);
-        } else {
-            $uuid = Uuid::fromString($uuid);
-        }
+        $uuid = strlen($uuid) === 16 ? Uuid::fromBytes($uuid) : Uuid::fromString($uuid);
 
         return static::load($uuid->getBytes(), $connection);
     }
 
-    public function isObjectReference($property)
+    /**
+     * @param string $property
+     *
+     * @return bool
+     */
+    public function isObjectReference(string $property): bool
     {
         return $property === 'parent' || in_array($property, $this->objectReferences);
     }
 
-    public function isBooleanProperty($property)
+    /**
+     * @param string $property
+     *
+     * @return bool
+     */
+    public function isBooleanProperty(string $property): bool
     {
         return in_array($property, $this->booleanProperties);
     }
 
-    protected function isBinaryColumn($column)
+    protected function isBinaryColumn(string $column): bool
     {
         if ($this->isObjectReference($column)) {
             return true;
         }
 
-        if ($column === 'uuid' || substr($column, -5) === '_uuid') {
+        if ($column === 'uuid' || str_ends_with($column, '_uuid')) {
             return true;
         }
 
         return parent::isBinaryColumn($column);
     }
 
-    public function isDateTimeProperty($property)
+    /**
+     * @param string $property
+     *
+     * @return bool
+     */
+    public function isDateTimeProperty(string $property): bool
     {
         return in_array($property, $this->dateTimeProperties);
     }
 
     /**
-     * @param $properties
+     * @param object $properties
      * @param VCenter $vCenter
+     *
      * @return $this
      */
-    public function setMapped($properties, VCenter $vCenter)
+    public function setMapped(object $properties, VCenter $vCenter): static
     {
         if ($this->hasProperty('vcenter_uuid')) {
             $this->set('vcenter_uuid', $vCenter->getUuid());
@@ -96,7 +109,7 @@ public function setMapped($properties, VCenter $vCenter)
                     // Like HostNumericSensorInfo.healthState
                     // Hint: lcfirst -> issue #179, vSphere 7 ships 'Green' instead of 'green',
                     //       at least on that specific system
-                    $value = \lcfirst($value->key);
+                    $value = lcfirst($value->key);
                 }
                 if ($property === 'customValues') {
                     if (empty((array) $value)) {
@@ -113,8 +126,11 @@ public function setMapped($properties, VCenter $vCenter)
         return $this;
     }
 
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    /**
+     * @return object
+     */
+    public function jsonSerialize(): object
     {
         $serialized = [];
         foreach ($this->getProperties() as $key => $value) {
@@ -122,7 +138,7 @@ public function jsonSerialize()
                 $value = DbProperty::dbToBoolean($value);
             } elseif ($this->isObjectReference($key)) {
                 $value = Uuid::fromBytes($value)->toString();
-            } elseif ($key === 'uuid' || substr($key, -5) === '_uuid') { // Hint: SHOULD be keys or references
+            } elseif ($key === 'uuid' || str_ends_with($key, '_uuid')) { // Hint: SHOULD be keys or references
                 if (strlen($value) === 16) {
                     $value = Uuid::fromBytes($value)->toString();
                 } elseif ($value !== null) {
@@ -139,44 +155,60 @@ public function jsonSerialize()
         return (object) $serialized;
     }
 
-    public static function fromSerialization($any)
+    /**
+     * @param mixed $any
+     *
+     * @return static
+     */
+    public static function fromSerialization(mixed $any): static
     {
         return static::create((array) $any);
     }
 
-    protected function createUuidForMoref($value, VCenter $vCenter)
+    /**
+     * @param mixed $value
+     * @param VCenter $vCenter
+     *
+     * @return ?string
+     */
+    protected function createUuidForMoref(mixed $value, VCenter $vCenter): ?string
     {
         if (empty($value)) {
             return null;
-        } elseif ($value instanceof ManagedObjectReference) {
+        }
+
+        if ($value instanceof ManagedObjectReference) {
             return $vCenter->makeBinaryGlobalMoRefUuid($value);
-        } else {
-            return $vCenter->makeBinaryGlobalUuid($value);
         }
+
+        return $vCenter->makeBinaryGlobalUuid($value);
     }
 
     /**
-     * @return ManagedObject
-     * @throws \Icinga\Exception\NotFoundError
+     * @return ?ManagedObject
+     *
+     * @throws NotFoundError
      */
-    public function object()
+    public function object(): ?ManagedObject
     {
-        if ($this->object === null) {
-            $this->object = ManagedObject::load($this->get('uuid'), $this->connection);
-        }
-
-        return $this->object;
+        return $this->object ??= ManagedObject::load($this->get('uuid'), $this->connection);
     }
 
-    public function setManagedObject(?ManagedObject $object)
+    /**
+     * @param ?ManagedObject $object
+     *
+     * @return void
+     */
+    public function setManagedObject(?ManagedObject $object): void
     {
         if ($object === null) {
             $this->object = null;
+
             return;
         }
 
         if ($object->get('uuid') !== $this->get('uuid')) {
-            throw new \InvalidArgumentException(sprintf(
+            throw new InvalidArgumentException(sprintf(
                 'Cannot set ManagedObject UUID %s, expected %s',
                 Uuid::fromBytes($object->get('uuid'))->toString(),
                 Uuid::fromBytes($this->get('uuid'))->toString()
@@ -186,17 +218,22 @@ public function setManagedObject(?ManagedObject $object)
         $this->object = $object;
     }
 
-    public static function getType()
+    /**
+     * @return false|string
+     */
+    public static function getType(): false|string
     {
         $parts = explode('\\', get_class(static::create()));
+
         return end($parts);
     }
 
     /**
      * @param VCenter $vCenter
+     *
      * @return static[]
      */
-    public static function loadAllForVCenter(VCenter $vCenter)
+    public static function loadAllForVCenter(VCenter $vCenter): array
     {
         $dummy = new static();
         $connection = $vCenter->getConnection();
diff --git a/library/Vspheredb/DbObject/BaseVmHardwareDbObject.php b/library/Vspheredb/DbObject/BaseVmHardwareDbObject.php
index 36737150..7a7d14c2 100644
--- a/library/Vspheredb/DbObject/BaseVmHardwareDbObject.php
+++ b/library/Vspheredb/DbObject/BaseVmHardwareDbObject.php
@@ -4,9 +4,9 @@
 
 abstract class BaseVmHardwareDbObject extends BaseDbObject
 {
-    protected $keyName = ['vm_uuid', 'hardware_key'];
+    protected string|array|null $keyName = ['vm_uuid', 'hardware_key'];
 
-    public function setMapped($properties, VCenter $vCenter)
+    public function setMapped($properties, VCenter $vCenter): static
     {
         $properties = (object) $properties;
         $this->set('vcenter_uuid', $vCenter->get('uuid'));
@@ -31,11 +31,7 @@ public function setMapped($properties, VCenter $vCenter)
         return $this;
     }
 
-    /**
-     * @param VCenter $vCenter
-     * @return static[]
-     */
-    public static function loadAllForVCenter(VCenter $vCenter)
+    public static function loadAllForVCenter(VCenter $vCenter): array
     {
         $dummy = new static();
         $objects = static::loadAll(
diff --git a/library/Vspheredb/DbObject/ComputeCluster.php b/library/Vspheredb/DbObject/ComputeCluster.php
index c92e334b..25245b50 100644
--- a/library/Vspheredb/DbObject/ComputeCluster.php
+++ b/library/Vspheredb/DbObject/ComputeCluster.php
@@ -4,12 +4,12 @@
 
 class ComputeCluster extends BaseDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
     // TODO: protected $table = 'compute_cluster';
-    protected $table = 'object';
+    protected ?string $table = 'object';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'           => null,
         'vcenter_uuid'   => null,
         'moref'          => null,
@@ -18,11 +18,10 @@ class ComputeCluster extends BaseDbObject
         'overall_status' => null,
         'level'          => null,
         'parent_uuid'    => null,
-        'tags'           => null,
+        'tags'           => null
     ];
 
-    protected $propertyMap = [
-    ];
+    protected array $propertyMap = [];
 
     public function calculateStats()
     {
@@ -43,7 +42,10 @@ public function calculateStats()
         );
     }
 
-    public function countHosts()
+    /**
+     * @return false|string|null
+     */
+    public function countHosts(): false|string|null
     {
         $db = $this->getDb();
         return $db->fetchOne(
diff --git a/library/Vspheredb/DbObject/ComputeResource.php b/library/Vspheredb/DbObject/ComputeResource.php
index fbbfca74..806b4c3e 100644
--- a/library/Vspheredb/DbObject/ComputeResource.php
+++ b/library/Vspheredb/DbObject/ComputeResource.php
@@ -4,11 +4,11 @@
 
 class ComputeResource extends BaseDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'compute_resource';
+    protected ?string $table = 'compute_resource';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'                     => null,
         'vcenter_uuid'             => null,
         'effective_cpu_mhz'        => null,
@@ -18,10 +18,10 @@ class ComputeResource extends BaseDbObject
         'effective_hosts'          => null,
         'hosts'                    => null,
         'total_cpu_mhz'            => null,
-        'total_memory_size_mb'     => null,
+        'total_memory_size_mb'     => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'summary.effectiveCpu'      => 'effective_cpu_mhz',
         'summary.effectiveMemory'   => 'effective_memory_size_mb',
         'summary.numCpuCores'       => 'cpu_cores',
@@ -30,6 +30,6 @@ class ComputeResource extends BaseDbObject
         'summary.numHosts'          => 'hosts',
         // 'summary.overallStatus' => '',
         'summary.totalCpu'          => 'total_cpu_mhz',
-        'summary.totalMemory'       => 'total_memory_size_mb',
+        'summary.totalMemory'       => 'total_memory_size_mb'
     ];
 }
diff --git a/library/Vspheredb/DbObject/CustomValueSupport.php b/library/Vspheredb/DbObject/CustomValueSupport.php
index 50e8ba56..22e0b3b4 100644
--- a/library/Vspheredb/DbObject/CustomValueSupport.php
+++ b/library/Vspheredb/DbObject/CustomValueSupport.php
@@ -2,28 +2,28 @@
 
 namespace Icinga\Module\Vspheredb\DbObject;
 
+use gipfl\Json\JsonEncodeException;
 use gipfl\Json\JsonString;
 
 trait CustomValueSupport
 {
     /**
-     * @param $value
-     * @throws \gipfl\Json\JsonEncodeException
+     * @param mixed $value
+     *
+     * @return void
+     *
+     * @throws JsonEncodeException
      */
-    protected function setCustomValues($value)
+    protected function setCustomValues(mixed $value): void
     {
-        if ($value === null) {
-            $this->set('custom_values', null);
-        } else {
-            $this->set('custom_values', JsonString::encode($value));
-        }
+        $this->set('custom_values', $value === null ? null : JsonString::encode($value));
     }
 
 
     /**
      * @return CustomValues
      */
-    public function customValues()
+    public function customValues(): CustomValues
     {
         return CustomValues::fromJson($this->get('custom_values'));
     }
diff --git a/library/Vspheredb/DbObject/CustomValues.php b/library/Vspheredb/DbObject/CustomValues.php
index 29775c5c..53655a2e 100644
--- a/library/Vspheredb/DbObject/CustomValues.php
+++ b/library/Vspheredb/DbObject/CustomValues.php
@@ -4,29 +4,48 @@
 
 use gipfl\Json\JsonString;
 use JsonSerializable;
+use ReturnTypeWillChange;
 
 class CustomValues implements JsonSerializable
 {
-    protected $values = [];
+    protected array $values = [];
 
-    public static function create(?array $values = null)
+    /**
+     * @param ?array $values
+     *
+     * @return static
+     */
+    public static function create(?array $values = null): static
     {
         return new static($values);
     }
 
-    public static function fromJson($string)
+    /**
+     * @param ?string $string $string
+     *
+     * @return static
+     */
+    public static function fromJson(?string $string): static
     {
         return new static((array) JsonString::decodeOptional($string));
     }
 
-    public function isEmpty()
+    /**
+     * @return bool
+     */
+    public function isEmpty(): bool
     {
         return empty($this->values);
     }
 
-    public function has($key)
+    /**
+     * @param string $key
+     *
+     * @return bool
+     */
+    public function has(string $key): bool
     {
-        return \array_key_exists($key, $this->values);
+        return array_key_exists($key, $this->values);
     }
 
     /**
@@ -41,47 +60,56 @@ public function remove(string $key): void
 
     /**
      * @param string $key
-     * @param $value
+     * @param mixed $value
      *
      * @return void
      */
-    public function set(string $key, $value): void
+    public function set(string $key, mixed $value): void
     {
         $this->values[$key] = $value;
     }
 
     /**
      * @param string $key
-     * @param $default
+     * @param mixed $default
      *
-     * @return mixed|null
+     * @return ?mixed
      */
-    public function get(string $key, $default = null): mixed
+    public function get(string $key, mixed $default = null): mixed
     {
         if ($this->has($key)) {
             return $this->values[$key];
-        } else {
-            return $default;
         }
+
+        return $default;
     }
 
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    /**
+     * @return object
+     */
+    public function jsonSerialize(): object
     {
         return (object) $this->values;
     }
 
-    public function toArray()
+    /**
+     * @return array
+     */
+    public function toArray(): array
     {
         return $this->values;
     }
 
+    /**
+     * @param ?array $values
+     */
     protected function __construct(?array $values = null)
     {
         if ($values === null) {
             return;
-        } else {
-            $this->values = $values;
         }
+
+        $this->values = $values;
     }
 }
diff --git a/library/Vspheredb/DbObject/Datastore.php b/library/Vspheredb/DbObject/Datastore.php
index 5dbeda5f..062597ac 100644
--- a/library/Vspheredb/DbObject/Datastore.php
+++ b/library/Vspheredb/DbObject/Datastore.php
@@ -4,11 +4,11 @@
 
 class Datastore extends BaseDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'datastore';
+    protected ?string $table = 'datastore';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'                   => null,
         'vcenter_uuid'           => null,
         'maintenance_mode'       => null,
@@ -18,16 +18,16 @@ class Datastore extends BaseDbObject
         'uncommitted'            => null,
         'is_accessible'          => null,
         'multiple_host_access'   => null,
-        'ts_last_forced_refresh' => null,
+        'ts_last_forced_refresh' => null
     ];
 
-    protected $booleanProperties = [
+    protected array $booleanProperties = [
         'is_accessible',
         'multiple_host_access',
         'ssd'
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'summary.maintenanceMode'    => 'maintenance_mode', // "normal"
         'summary.accessible'         => 'is_accessible',
         'summary.freeSpace'          => 'free_space',
diff --git a/library/Vspheredb/DbObject/DbProperty.php b/library/Vspheredb/DbObject/DbProperty.php
index 3b2a00c7..45d921d5 100644
--- a/library/Vspheredb/DbObject/DbProperty.php
+++ b/library/Vspheredb/DbObject/DbProperty.php
@@ -7,42 +7,32 @@
 class DbProperty
 {
     /**
-     * @param ?boolean $value
-     * @return null|string
+     * @param ?bool $value
+     *
+     * @return ?string
      */
-    public static function booleanToDb($value)
+    public static function booleanToDb(?bool $value): ?string
     {
-        if ($value === true) {
-            return 'y';
-        } elseif ($value === false) {
-            return 'n';
-        } elseif ($value === null) {
-            return null;
-        } else {
-            throw new InvalidArgumentException(
-                'Boolean expected, got %s',
-                var_export($value, 1)
-            );
-        }
+        return match ($value) {
+            true    => 'y',
+            false   => 'n',
+            null    => null,
+            default => throw new InvalidArgumentException(sprintf('Boolean expected, got %s', var_export($value, 1)))
+        };
     }
 
     /**
      * @param ?string $value
-     * @return bool|null
+     *
+     * @return ?bool
      */
-    public static function dbToBoolean($value)
+    public static function dbToBoolean(?string $value): ?bool
     {
-        if ($value === 'y') {
-            return true;
-        } elseif ($value === 'n') {
-            return false;
-        } elseif ($value === null) {
-            return null;
-        } else {
-            throw new InvalidArgumentException(
-                'Boolean expected, got %s',
-                var_export($value, 1)
-            );
-        }
+        return match ($value) {
+            'y'     => true,
+            'n'     => false,
+            null    => null,
+            default => throw new InvalidArgumentException(sprintf('Boolean expected, got %s', var_export($value, 1)))
+        };
     }
 }
diff --git a/library/Vspheredb/DbObject/DistributedVirtualPortgroup.php b/library/Vspheredb/DbObject/DistributedVirtualPortgroup.php
index 6c70c159..4e379e59 100644
--- a/library/Vspheredb/DbObject/DistributedVirtualPortgroup.php
+++ b/library/Vspheredb/DbObject/DistributedVirtualPortgroup.php
@@ -6,39 +6,49 @@
 
 class DistributedVirtualPortgroup extends BaseDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'distributed_virtual_portgroup';
+    protected ?string $table = 'distributed_virtual_portgroup';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'           => null,
         'vcenter_uuid'   => null,
         'portgroup_type' => null,
         'distributed_virtual_switch_uuid' => null,
         'vlan'         => null,
         'vlan_ranges'  => null,
-        'num_ports'    => null,
+        'num_ports'    => null
     ];
 
-    protected $objectReferences = [
+    protected array $objectReferences = [
         'distributed_virtual_switch_uuid'
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'config.defaultPortConfig' => 'defaultPortConfig',
         'config.numPorts' => 'num_ports',
         'config.type'     => 'portgroup_type',
-        'config.distributedVirtualSwitch' => 'distributed_virtual_switch_uuid',
+        'config.distributedVirtualSwitch' => 'distributed_virtual_switch_uuid'
     ];
 
-    protected function setDefaultPortConfig($config)
+    /**
+     * @param object $config
+     *
+     * @return void
+     */
+    protected function setDefaultPortConfig(object $config): void
     {
         if (property_exists($config, 'vlan')) {
             $this->setDefaultVlan($config->vlan->vlanId);
         }
     }
 
-    protected function setDefaultVlan($vlan)
+    /**
+     * @param mixed $vlan
+     *
+     * @return void
+     */
+    protected function setDefaultVlan(mixed $vlan): void
     {
         if (is_array($vlan)) {
             $ranges = [];
@@ -46,7 +56,7 @@ protected function setDefaultVlan($vlan)
             foreach ($vlan as $range) {
                 $ranges[] = (object) [
                     'end'   => $range->end,
-                    'start' => $range->start,
+                    'start' => $range->start
                 ];
             }
             $this->set('vlan_ranges', json_encode($ranges));
diff --git a/library/Vspheredb/DbObject/DistributedVirtualSwitch.php b/library/Vspheredb/DbObject/DistributedVirtualSwitch.php
index f3a36139..6e0dcd30 100644
--- a/library/Vspheredb/DbObject/DistributedVirtualSwitch.php
+++ b/library/Vspheredb/DbObject/DistributedVirtualSwitch.php
@@ -10,11 +10,11 @@
  */
 class DistributedVirtualSwitch extends BaseDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'distributed_virtual_switch';
+    protected ?string $table = 'distributed_virtual_switch';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'                 => null,
         'vcenter_uuid'         => null,
         'description'          => null,
@@ -23,10 +23,10 @@ class DistributedVirtualSwitch extends BaseDbObject
         'max_ports'            => null,
         'hostmembers_checksum' => null,
         'portgroups_checksum'  => null,
-        'vms_checksum'         => null,
+        'vms_checksum'         => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         // 'portgroup'           => 'portGroups',
         'config.description'     => 'description',
         // config.uuid?
@@ -35,56 +35,51 @@ class DistributedVirtualSwitch extends BaseDbObject
         'summary.numHosts'       => 'num_hosts',
         'config.numPorts'        => 'num_ports',
         'config.maxPorts'        => 'max_ports',
-        'config.uplinkPortgroup' => 'uplinkPortGroups',
+        'config.uplinkPortgroup' => 'uplinkPortGroups'
     ];
 
-    protected $unstoredPortGroupRefs;
+    protected ?array $unstoredPortGroupRefs = null;
 
-    public function setUplinkPortGroups($portGroups)
+    /**
+     * @param array $portGroups
+     *
+     * @return void
+     */
+    public function setUplinkPortGroups(array $portGroups): void
     {
         var_dump('UPLINK');
         var_dump($portGroups);
     }
 
-    public function XXXXsetPortGroups($portGroups)
-    {
-        $newSum = $this->calculateMorefsChecksum($portGroups);
-        if ($this->get('portgroups_checksum') !== $newSum) {
-            $this->scheduleNewPortgroupRefs($portGroups);
-        }
-    }
-
     /**
      * @param ManagedObjectReference[] $hostMembers
+     *
+     * @return void
      */
-    public function setHostMembers($hostMembers)
+    public function setHostMembers(array $hostMembers): void
     {
         var_dump('HOSTMEMBERS');
         var_dump($hostMembers);
-        return;
-        $newSum = $this->calculateMorefsChecksum($hostMembers);
-        if ($this->get('hostmembers_checksum') !== $newSum) {
-            $this->scheduleNewPortgroupRefs($hostMembers);
-        }
     }
 
-    protected function scheduleNewPortgroupRefs($portGroups)
+    /**
+     * @param array $portGroups
+     *
+     * @return void
+     */
+    protected function scheduleNewPortgroupRefs(array $portGroups): void
     {
         $this->unstoredPortGroupRefs = $portGroups;
     }
 
-    protected function onStore()
-    {
-        if (false && $this->unstoredPortGroupRefs) {
-            $this->replaceMoRefs(
-                $this->get('uuid'),
-                'distributed_switch_portgroup',
-                $this->unstoredPortGroupRefs
-            );
-        }
-    }
-
-    protected function replaceMoRefs($uuid, $table, $refs)
+    /**
+     * @param string $uuid
+     * @param string $table
+     * @param array $refs
+     *
+     * @return void
+     */
+    protected function replaceMoRefs(string $uuid, string $table, array $refs): void
     {
         // TODO: WHAAAAAAAAAAAAAAT?
         $vCenter = VCenter::loadWithAutoIncId(1, $this->getConnection());
@@ -101,7 +96,12 @@ protected function replaceMoRefs($uuid, $table, $refs)
         }
     }
 
-    protected function calculateMorefsChecksum($moRefs)
+    /**
+     * @param array $moRefs
+     *
+     * @return string
+     */
+    protected function calculateMorefsChecksum(array $moRefs): string
     {
         $names = [];
         foreach ($moRefs as $moRef) {
@@ -109,6 +109,7 @@ protected function calculateMorefsChecksum($moRefs)
         }
 
         sort($names);
+
         return sha1(implode('|', $names), true);
     }
 }
diff --git a/library/Vspheredb/DbObject/HostHba.php b/library/Vspheredb/DbObject/HostHba.php
index 365fd067..0e4d04c0 100644
--- a/library/Vspheredb/DbObject/HostHba.php
+++ b/library/Vspheredb/DbObject/HostHba.php
@@ -4,11 +4,11 @@
 
 class HostHba extends BaseVmHardwareDbObject
 {
-    protected $keyName = ['host_uuid', 'hba_key'];
+    protected string|array|null $keyName = ['host_uuid', 'hba_key'];
 
-    protected $table = 'host_hba';
+    protected ?string $table = 'host_hba';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'host_uuid'       => null,
         'hba_key'         => null,
         'device'          => null,
@@ -18,16 +18,16 @@ class HostHba extends BaseVmHardwareDbObject
         'pci'             => null,
         'status'          => null,
         'storage_protocol' => 'scsi',
-        'vcenter_uuid'    => null,
+        'vcenter_uuid'    => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'device'          => 'device',
         'bus'             => 'bus',
         'driver'          => 'driver',
         'model'           => 'model',
         'pci'             => 'pci',
         'status'          => 'status',
-        'storageProtocol' => 'storage_protocol',
+        'storageProtocol' => 'storage_protocol'
     ];
 }
diff --git a/library/Vspheredb/DbObject/HostPciDevice.php b/library/Vspheredb/DbObject/HostPciDevice.php
index d50f9527..3c86f452 100644
--- a/library/Vspheredb/DbObject/HostPciDevice.php
+++ b/library/Vspheredb/DbObject/HostPciDevice.php
@@ -2,11 +2,13 @@
 
 namespace Icinga\Module\Vspheredb\DbObject;
 
+use Icinga\Exception\IcingaException;
+
 class HostPciDevice extends BaseDbObject
 {
-    protected $table = 'host_pci_device';
+    protected ?string $table = 'host_pci_device';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'id'              => null,
         'host_uuid'       => null,
         'bus'             => null,
@@ -20,14 +22,14 @@ class HostPciDevice extends BaseDbObject
         'vendor_name'     => null,
         'sub_vendor_id'   => null,
         'parent_bridge'   => null,
-        'vcenter_uuid'    => null,
+        'vcenter_uuid'    => null
     ];
 
-    protected $objectReferences = [
-        'host_uuid',
+    protected array $objectReferences = [
+        'host_uuid'
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'id'           => 'id',
         'bus'          => 'bus',
         'slot'         => 'slot',
@@ -39,12 +41,12 @@ class HostPciDevice extends BaseDbObject
         'vendorId'     => 'vendor_id',
         'vendorName'   => 'vendor_name',
         'subVendorId'  => 'sub_vendor_id',
-        'parentBridge' => 'parent_bridge',
+        'parentBridge' => 'parent_bridge'
     ];
 
-    protected $keyName = ['host_uuid', 'id'];
+    protected string|array|null $keyName = ['host_uuid', 'id'];
 
-    public function setMapped($properties, VCenter $vCenter)
+    public function setMapped(object $properties, VCenter $vCenter): static
     {
         $this->set('vcenter_uuid', $vCenter->get('uuid'));
 
@@ -58,6 +60,7 @@ public function setMapped($properties, VCenter $vCenter)
                         var_dump(is_int($properties->$key));
                         var_dump($properties->$key);
                         var_dump($properties);
+
                         exit;
                     }
                 } else {
@@ -73,10 +76,12 @@ public function setMapped($properties, VCenter $vCenter)
 
     /**
      * @param VCenter $vCenter
+     *
      * @return static[]
-     * @throws \Icinga\Exception\IcingaException
+     *
+     * @throws IcingaException
      */
-    public static function loadAllForVCenter(VCenter $vCenter)
+    public static function loadAllForVCenter(VCenter $vCenter): array
     {
         $dummy = new static();
         $objects = static::loadAll(
diff --git a/library/Vspheredb/DbObject/HostPhysicalNic.php b/library/Vspheredb/DbObject/HostPhysicalNic.php
index 91e2d585..0337f35e 100644
--- a/library/Vspheredb/DbObject/HostPhysicalNic.php
+++ b/library/Vspheredb/DbObject/HostPhysicalNic.php
@@ -4,11 +4,11 @@
 
 class HostPhysicalNic extends BaseVmHardwareDbObject
 {
-    protected $keyName = ['host_uuid', 'nic_key'];
+    protected string|array|null $keyName = ['host_uuid', 'nic_key'];
 
-    protected $table = 'host_physical_nic';
+    protected ?string $table = 'host_physical_nic';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'host_uuid'                => null,
         'nic_key'                  => null,
         'auto_negotiate_supported' => null,
@@ -18,21 +18,21 @@ class HostPhysicalNic extends BaseVmHardwareDbObject
         'link_duplex'              => null,
         'mac_address'              => null,
         'pci'                      => null,
-        'vcenter_uuid'             => null,
+        'vcenter_uuid'             => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'device'                 => 'device',
         'driver'                 => 'driver',
         'pci'                    => 'pci',
         'linkSpeed.speedMb'      => 'link_speed_mb',
         'linkSpeed.duplex'       => 'link_duplex',
         'mac'                    => 'mac_address',
-        'autoNegotiateSupported' => 'auto_negotiate_supported',
+        'autoNegotiateSupported' => 'auto_negotiate_supported'
     ];
 
-    protected $booleanProperties = [
+    protected array $booleanProperties = [
         'auto_negotiate_supported',
-        'link_duplex',
+        'link_duplex'
     ];
 }
diff --git a/library/Vspheredb/DbObject/HostQuickStats.php b/library/Vspheredb/DbObject/HostQuickStats.php
index c5062da9..76dccf48 100644
--- a/library/Vspheredb/DbObject/HostQuickStats.php
+++ b/library/Vspheredb/DbObject/HostQuickStats.php
@@ -6,41 +6,55 @@
 
 class HostQuickStats extends BaseDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'host_quick_stats';
+    protected ?string $table = 'host_quick_stats';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'                        => null,
         'distributed_cpu_fairness'    => null,
         'distributed_memory_fairness' => null,
         'overall_cpu_usage'           => null,
         'overall_memory_usage_mb'     => null,
         'uptime'                      => null,
-        'vcenter_uuid'                => null,
+        'vcenter_uuid'                => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'summary.quickStats.distributedCpuFairness'    => 'distributed_cpu_fairness',
         'summary.quickStats.distributedMemoryFairness' => 'distributed_memory_fairness',
         'summary.quickStats.overallCpuUsage'           => 'overall_cpu_usage',
         'summary.quickStats.overallMemoryUsage'        => 'overall_memory_usage_mb',
-        'summary.quickStats.uptime'                    => 'uptime',
+        'summary.quickStats.uptime'                    => 'uptime'
     ];
 
-    protected static $preloadCache = null;
+    /** @var ?static[] */
+    protected static ?array $preloadCache = null;
 
-    public static function preloadAll(Db $db)
+    /**
+     * @param Db $db
+     *
+     * @return void
+     */
+    public static function preloadAll(Db $db): void
     {
         self::$preloadCache = self::loadAll($db, null, 'uuid');
     }
 
-    public static function clearPreloadCache()
+    /**
+     * @return void
+     */
+    public static function clearPreloadCache(): void
     {
         self::$preloadCache = null;
     }
 
-    public static function loadFor(HostSystem $object)
+    /**
+     * @param HostSystem $object
+     *
+     * @return static
+     */
+    public static function loadFor(HostSystem $object): static
     {
         if ($object->hasBeenLoadedFromDb()) {
             $connection = $object->getConnection();
diff --git a/library/Vspheredb/DbObject/HostSensor.php b/library/Vspheredb/DbObject/HostSensor.php
index b8ef19d6..0ac8c542 100644
--- a/library/Vspheredb/DbObject/HostSensor.php
+++ b/library/Vspheredb/DbObject/HostSensor.php
@@ -4,9 +4,9 @@
 
 class HostSensor extends BaseDbObject
 {
-    protected $table = 'host_sensor';
+    protected ?string $table = 'host_sensor';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'name'            => null,
         'host_uuid'       => null,
         'health_state'    => null,
@@ -15,27 +15,32 @@ class HostSensor extends BaseDbObject
         'base_units'      => null,
         'rate_units'      => null,
         'sensor_type'     => null,
-        'vcenter_uuid'    => null,
+        'vcenter_uuid'    => null
     ];
 
-    protected $objectReferences = [
-        'host_uuid',
+    protected array $objectReferences = [
+        'host_uuid'
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'name'           => 'name',
         'healthState'    => 'health_state',
         'currentReading' => 'current_reading',
         'unitModifier'   => 'unit_modifier',
         'baseUnits'      => 'base_units',
         'rateUnits'      => 'rate_units',
-        'sensorType'     => 'sensor_type',
+        'sensorType'     => 'sensor_type'
     ];
 
     // TODO: HostNumericSensorInfo has 'id' since v6.5
-    protected $keyName = ['host_uuid', 'name'];
+    protected string|array|null $keyName = ['host_uuid', 'name'];
 
-    public function setName($value)
+    /**
+     * @param string $value
+     *
+     * @return static
+     */
+    public function setName(string $value): static
     {
         // name has the form "description --- state/identifier"
         // TODO: strip the identifier once we changed the key to 'id'
@@ -43,25 +48,17 @@ public function setName($value)
         // $value = \preg_replace('/\s---\s.+$/', '', $value);
         if ($value === $this->get('name')) {
             return $this;
-        } else {
-            return $this->reallySet('name', $value);
         }
+
+        return $this->reallySet('name', $value);
     }
 
-    public function setHealth_state($healthState) // phpcs:ignore
+    public function setHealth_state($healthState): void // phpcs:ignore
     {
-        if (is_object($healthState)) {
-            $this->reallySet('health_state', lcfirst($healthState->key));
-        } else {
-            $this->reallySet('health_state', $healthState);
-        }
+        $this->reallySet('health_state', is_object($healthState) ? lcfirst($healthState->key) : $healthState);
     }
 
-    /**
-     * @param VCenter $vCenter
-     * @return static[]
-     */
-    public static function loadAllForVCenter(VCenter $vCenter)
+    public static function loadAllForVCenter(VCenter $vCenter): array
     {
         $dummy = new static();
         $objects = static::loadAll(
diff --git a/library/Vspheredb/DbObject/HostSystem.php b/library/Vspheredb/DbObject/HostSystem.php
index 83e157a4..b5c10644 100644
--- a/library/Vspheredb/DbObject/HostSystem.php
+++ b/library/Vspheredb/DbObject/HostSystem.php
@@ -4,16 +4,17 @@
 
 use DateTime;
 use Icinga\Module\Vspheredb\MappedClass\ClusterDasFdmHostState;
+use stdClass;
 
 class HostSystem extends BaseDbObject
 {
     use CustomValueSupport;
 
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'host_system';
+    protected ?string $table = 'host_system';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'                    => null,
         'vcenter_uuid'            => null,
         'host_name'               => null,
@@ -35,10 +36,10 @@ class HostSystem extends BaseDbObject
         'hardware_num_nic'        => null,
         'runtime_power_state'     => null,
         'das_host_state'          => null,
-        'custom_values'           => null,
+        'custom_values'           => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         // config.fileSystemVolume.mountInfo
         'name'                              => 'host_name',
         'summary.config.product.apiVersion' => 'product_api_version',
@@ -60,10 +61,13 @@ class HostSystem extends BaseDbObject
         'summary.hardware.cpuMhz'           => 'hardware_cpu_mhz',
         'summary.hardware.cpuModel'         => 'hardware_cpu_model',
         'summary.hardware.numHBAs'          => 'hardware_num_hba',
-        'summary.hardware.numNics'          => 'hardware_num_nic',
+        'summary.hardware.numNics'          => 'hardware_num_nic'
     ];
 
-    public function countVms()
+    /**
+     * @return string
+     */
+    public function countVms(): string
     {
         $db = $this->getDb();
         return $db->fetchOne(
@@ -73,7 +77,7 @@ public function countVms()
         );
     }
 
-    public function setMapped($properties, VCenter $vCenter)
+    public function setMapped(object $properties, VCenter $vCenter): static
     {
         $otherInfo = $properties->{'summary.hardware.otherIdentifyingInfo'};
         if (property_exists($otherInfo, 'HostSystemIdentificationInfo')) {
@@ -95,7 +99,12 @@ public function setMapped($properties, VCenter $vCenter)
         return parent::setMapped($properties, $vCenter);
     }
 
-    protected function setOtherIdentifyingInfo($infos)
+    /**
+     * @param mixed $infos
+     *
+     * @return void
+     */
+    protected function setOtherIdentifyingInfo(mixed $infos): void
     {
         foreach ($infos as $info) {
             if ($info->identifierType->key === 'ServiceTag') {
@@ -107,17 +116,22 @@ protected function setOtherIdentifyingInfo($infos)
         }
     }
 
-    protected function setDasHostState($state = null)
+    /**
+     * @param ClusterDasFdmHostState|stdClass|null $state
+     *
+     * @return void
+     */
+    protected function setDasHostState(ClusterDasFdmHostState|stdClass|null $state = null): void
     {
-        if ($state === null) {
-            $this->set('das_host_state', null);
-        } else {
-            /** @var ClusterDasFdmHostState|\stdClass $state */
-            $this->set('das_host_state', $state->state);
-        }
+        $this->set('das_host_state', $state?->state);
     }
 
-    protected function formatBiosReleaseDate($date)
+    /**
+     * @param string $date
+     *
+     * @return string
+     */
+    protected function formatBiosReleaseDate(string $date): string
     {
         return (new DateTime($date))->format('Y-m-d H:i:s');
     }
diff --git a/library/Vspheredb/DbObject/HostVirtualNic.php b/library/Vspheredb/DbObject/HostVirtualNic.php
index eda20cd8..cdd4e2ae 100644
--- a/library/Vspheredb/DbObject/HostVirtualNic.php
+++ b/library/Vspheredb/DbObject/HostVirtualNic.php
@@ -4,11 +4,11 @@
 
 class HostVirtualNic extends BaseVmHardwareDbObject
 {
-    protected $keyName = ['host_uuid', 'nic_key'];
+    protected string|array|null $keyName = ['host_uuid', 'nic_key'];
 
-    protected $table = 'host_virtual_nic';
+    protected ?string $table = 'host_virtual_nic';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'host_uuid'              => null,
         'nic_key'                => null,
         'net_stack_instance_key' => null,
@@ -31,10 +31,10 @@ class HostVirtualNic extends BaseVmHardwareDbObject
         // pinnedPnic?
         'device'                 => null,
         'tso_enabled'            => null,
-        'vcenter_uuid'           => null,
+        'vcenter_uuid'           => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'device'                      => 'device',
         'port'                        => 'port',
         'portgroup'                   => 'portgroup',
@@ -52,6 +52,6 @@ class HostVirtualNic extends BaseVmHardwareDbObject
         'spec.distributedVirtualPort.ip.ipV6Config.origin'     => 'ipv6_origin',
         */
         'spec.mac'        => 'mac_address',
-        'spec.distributedVirtualPort.tsoEnabled' => 'tso_enabled',
+        'spec.distributedVirtualPort.tsoEnabled' => 'tso_enabled'
     ];
 }
diff --git a/library/Vspheredb/DbObject/ManagedObject.php b/library/Vspheredb/DbObject/ManagedObject.php
index 01cb63fe..d3f5ec6a 100644
--- a/library/Vspheredb/DbObject/ManagedObject.php
+++ b/library/Vspheredb/DbObject/ManagedObject.php
@@ -2,19 +2,21 @@
 
 namespace Icinga\Module\Vspheredb\DbObject;
 
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\Db\DbObject as VspheredbDbObject;
 use Icinga\Module\Vspheredb\Db\DbUtil;
+use Icinga\Module\Vspheredb\Exception\DuplicateKeyException;
 use Ramsey\Uuid\Uuid;
 use RuntimeException;
 
 class ManagedObject extends VspheredbDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'object';
+    protected ?string $table = 'object';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'           => null,
         'vcenter_uuid'   => null,
         'moref'          => null,
@@ -23,33 +25,32 @@ class ManagedObject extends VspheredbDbObject
         'overall_status' => null,
         'level'          => null,
         'parent_uuid'    => null,
-        'tags'           => null,
+        'tags'           => null
     ];
 
-    /** @var ManagedObject */
-    private $parent;
+    private ?ManagedObject $parent = null;
 
     /**
      * @param string $uuid
      * @param Db $connection
+     *
      * @return static
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @throws NotFoundError
      */
     public static function loadWithUuid(string $uuid, Db $connection): ManagedObject
     {
-        if (strlen($uuid) === 16) {
-            $uuid = Uuid::fromBytes($uuid);
-        } else {
-            $uuid = Uuid::fromString($uuid);
-        }
+        $uuid = strlen($uuid) === 16 ? Uuid::fromBytes($uuid) : Uuid::fromString($uuid);
 
         return static::load($uuid->getBytes(), $connection);
     }
 
     /**
-     * @throws \Icinga\Module\Vspheredb\Exception\DuplicateKeyException
+     * @returns void
+     *
+     * @throws DuplicateKeyException
      */
-    protected function beforeStore()
+    protected function beforeStore(): void
     {
         if (null !== $this->parent) {
             $this->parent->store();
@@ -62,30 +63,38 @@ protected function beforeStore()
         $this->set('level', $this->calculateLevel());
     }
 
-    public function getBinaryUuid()
+    /**
+     * @return mixed
+     */
+    public function getBinaryUuid(): mixed
     {
         return $this->get('uuid');
     }
 
-    public function setParent(ManagedObject $object)
+    /**
+     * @param ManagedObject $object
+     *
+     * @return $this
+     */
+    public function setParent(ManagedObject $object): static
     {
         $this->parent = $object;
         // Hint: parent change hasn't been detected otherwise.
         // TODO: check whether change detection is still fine
-        if ($object->hasBeenLoadedFromDb()) {
-            $this->set('parent_uuid', $object->get('uuid'));
-        } else {
-            $this->set('parent_uuid', 'NOT YET, SETTING A TOO LONG STRING');
-        }
+        $this->set(
+            'parent_uuid',
+            $object->hasBeenLoadedFromDb() ? $object->get('uuid') : 'NOT YET, SETTING A TOO LONG STRING'
+        );
 
         return $this;
     }
 
     /**
      * @param VCenter $vCenter
+     *
      * @return static[]
      */
-    public static function loadAllForVCenter(VCenter $vCenter)
+    public static function loadAllForVCenter(VCenter $vCenter): array
     {
         $dummy = new static();
 
@@ -100,7 +109,10 @@ public static function loadAllForVCenter(VCenter $vCenter)
         );
     }
 
-    public function getNumericLevel()
+    /**
+     * @return int
+     */
+    public function getNumericLevel(): int
     {
         $level = $this->get('level');
         if ($level === null) {
@@ -110,18 +122,22 @@ public function getNumericLevel()
         return (int) $level;
     }
 
-    public function calculateLevel()
+    /**
+     * @return int
+     */
+    public function calculateLevel(): int
     {
-        if ($this->parent === null) {
-            return 0;
-        } else {
-            return $this->parent->calculateLevel() + 1;
-        }
+        return $this->parent === null ? 0 : $this->parent->calculateLevel() + 1;
     }
 
-    protected function isBinaryColumn($column)
+    /**
+     * @param string $column
+     *
+     * @return bool
+     */
+    protected function isBinaryColumn(string $column): bool
     {
-        if ($column === 'uuid' || substr($column, -5) === '_uuid') {
+        if ($column === 'uuid' || str_ends_with($column, '_uuid')) {
             return true;
         }
 
diff --git a/library/Vspheredb/DbObject/MappingHelper.php b/library/Vspheredb/DbObject/MappingHelper.php
index ed88b21f..f1952376 100644
--- a/library/Vspheredb/DbObject/MappingHelper.php
+++ b/library/Vspheredb/DbObject/MappingHelper.php
@@ -16,12 +16,12 @@ class MappingHelper
      * and a key vars.disk.sda given as [ 'vars', 'disk', 'sda' ] this would
      * return { size => '255GB' }
      *
-     * @param  string $val  The value to extract data from
-     * @param  array  $keys A list of nested keys pointing to desired data
+     * @param object|string|null $val The value to extract data from
+     * @param array $keys A list of nested keys pointing to desired data
      *
      * @return mixed
      */
-    public static function getDeepValue($val, array $keys)
+    public static function getDeepValue(object|string|null $val, array $keys): mixed
     {
         if ($val === null) {
             return null;
@@ -43,13 +43,14 @@ public static function getDeepValue($val, array $keys)
      *
      * Supports also keys pointing to nested structures like vars.disk.sda
      *
-     * @param  object $row stdClass object providing property values
-     * @param  string $var  Variable/property name
+     * @param object $row stdClass object providing property values
+     * @param string $var Variable/property name
+     *
      * @return mixed
      */
-    public static function getSpecificValue($row, $var)
+    public static function getSpecificValue(object $row, string $var): mixed
     {
-        if (strpos($var, '.') === false) {
+        if (! str_contains($var, '.')) {
             if ($row instanceof DbObject) {
                 return $row->$var;
             }
diff --git a/library/Vspheredb/DbObject/MoRefList.php b/library/Vspheredb/DbObject/MoRefList.php
index 6e1f10cf..1b5b7bbc 100644
--- a/library/Vspheredb/DbObject/MoRefList.php
+++ b/library/Vspheredb/DbObject/MoRefList.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\DbObject;
 
+use Exception;
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
+use Zend_Db_Adapter_Exception;
 
 abstract class MoRefList
 {
@@ -13,9 +15,10 @@ abstract class MoRefList
     /**
      * @param VCenter $vCenter
      * @param ManagedObjectReference[] $objects
+     *
      * @return string
      */
-    public static function requireChecksum(VCenter $vCenter, $objects)
+    public static function requireChecksum(VCenter $vCenter, array $objects): string
     {
         $key = static::calculateChecksum($vCenter, $objects);
 
@@ -27,11 +30,12 @@ public static function requireChecksum(VCenter $vCenter, $objects)
     }
 
     /**
-     * @param $checksum
+     * @param string $checksum
      * @param VCenter $vCenter
+     *
      * @return bool
      */
-    protected static function checksumExists($checksum, VCenter $vCenter)
+    protected static function checksumExists(string $checksum, VCenter $vCenter): bool
     {
         $db = $vCenter->getDb();
         return (int) $db->fetchOne(
@@ -42,11 +46,13 @@ protected static function checksumExists($checksum, VCenter $vCenter)
     }
 
     /**
-     * @param $checksum
+     * @param string $checksum
      * @param ManagedObjectReference[] $objects
      * @param VCenter $vCenter
+     *
+     * @return void
      */
-    protected static function create($checksum, $objects, VCenter $vCenter)
+    protected static function create(string $checksum, array $objects, VCenter $vCenter): void
     {
         $db = $vCenter->getDb();
         $db->beginTransaction();
@@ -61,10 +67,10 @@ protected static function create($checksum, $objects, VCenter $vCenter)
                 ]);
             }
             $db->commit();
-        } catch (\Zend_Db_Adapter_Exception $e) {
+        } catch (Zend_Db_Adapter_Exception $e) {
             try {
                 $db->rollBack();
-            } catch (\Exception $e) {
+            } catch (Exception $e) {
                 // There is nothing we can do about this
             }
 
@@ -75,9 +81,10 @@ protected static function create($checksum, $objects, VCenter $vCenter)
     /**
      * @param VCenter $vCenter
      * @param ManagedObjectReference[] $objects
+     *
      * @return string
      */
-    protected static function calculateChecksum(VCenter $vCenter, $objects)
+    protected static function calculateChecksum(VCenter $vCenter, array $objects): string
     {
         $list = [];
         foreach ($objects as $object) {
diff --git a/library/Vspheredb/DbObject/MonitoringConnection.php b/library/Vspheredb/DbObject/MonitoringConnection.php
index fd8b1cc5..f8311c8a 100644
--- a/library/Vspheredb/DbObject/MonitoringConnection.php
+++ b/library/Vspheredb/DbObject/MonitoringConnection.php
@@ -3,17 +3,19 @@
 namespace Icinga\Module\Vspheredb\DbObject;
 
 use Icinga\Exception\ConfigurationError;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Monitoring\Backend\MonitoringBackend;
 use Icinga\Module\Vspheredb\Ido;
 use RuntimeException;
+use Zend_Db_Adapter_Abstract;
 
 class MonitoringConnection extends BaseDbObject
 {
-    protected $keyName = 'id';
+    protected string|array|null $keyName = 'id';
 
-    protected $table = 'monitoring_connection';
+    protected ?string $table = 'monitoring_connection';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'id'                          => null,
         'vcenter_uuid'                => null,
         'priority'                    => null,
@@ -22,38 +24,42 @@ class MonitoringConnection extends BaseDbObject
         'host_property'               => null,
         'monitoring_host_property'    => null,
         'vm_property'                 => null,
-        'monitoring_vm_host_property' => null,
+        'monitoring_vm_host_property' => null
     ];
 
-    protected $monitoring;
+    protected ?Ido $monitoring = null;
 
     /**
      * @param VCenter $vCenter
-     * @return Ido|null
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @return ?Ido
+     *
+     * @throws NotFoundError
      */
-    public static function eventuallyLoadForVCenter(VCenter $vCenter)
+    public static function eventuallyLoadForVCenter(VCenter $vCenter): ?Ido
     {
         $db = $vCenter->getConnection();
         if (static::exists($vCenter->getUuid(), $db)) {
-            return static::load(
-                $vCenter->getUuid(),
-                $db
-            )->getMonitoring();
-        } else {
-            return null;
+            return static::load($vCenter->getUuid(), $db)->getMonitoring();
         }
+
+        return null;
     }
 
-    public function getIdoDb()
+    /**
+     * @return Zend_Db_Adapter_Abstract
+     */
+    public function getIdoDb(): Zend_Db_Adapter_Abstract
     {
-        /** @var \Icinga\Data\Db\DbConnection $resource */
-        $resource = $this->getMonitoringBackend()->getResource();
-
-        return $resource->getDbAdapter();
+        return $this->getMonitoringBackend()->getResource()->getDbAdapter();
     }
 
-    public function getMonitoringBackend()
+    /**
+     * @return MonitoringBackend
+     *
+     * @throws RuntimeException
+     */
+    public function getMonitoringBackend(): MonitoringBackend
     {
         $this->assertIdo();
 
@@ -64,7 +70,12 @@ public function getMonitoringBackend()
         }
     }
 
-    protected function assertIdo()
+    /**
+     * @return void
+     *
+     * @throws RuntimeException
+     */
+    protected function assertIdo(): void
     {
         if ($this->get('source_type') !== 'ido') {
             throw new RuntimeException(sprintf(
@@ -77,12 +88,8 @@ protected function assertIdo()
     /**
      * @return Ido
      */
-    public function getMonitoring()
+    public function getMonitoring(): Ido
     {
-        if ($this->monitoring === null) {
-            $this->monitoring = Ido::createByResourceName($this->get('source_resource_name'));
-        }
-
-        return $this->monitoring;
+        return $this->monitoring ??= Ido::createByResourceName($this->get('source_resource_name'));
     }
 }
diff --git a/library/Vspheredb/DbObject/StoragePod.php b/library/Vspheredb/DbObject/StoragePod.php
index 3d718ff0..da2849a0 100644
--- a/library/Vspheredb/DbObject/StoragePod.php
+++ b/library/Vspheredb/DbObject/StoragePod.php
@@ -4,21 +4,21 @@
 
 class StoragePod extends BaseDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'storage_pod';
+    protected ?string $table = 'storage_pod';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'         => null,
         'vcenter_uuid' => null,
         'pod_name'     => null,
         'free_space'   => null,
-        'capacity'     => null,
+        'capacity'     => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'name'              => 'pod_name',
         'summary.capacity'  => 'capacity',
-        'summary.freeSpace' => 'free_space',
+        'summary.freeSpace' => 'free_space'
     ];
 }
diff --git a/library/Vspheredb/DbObject/TaggingCategory.php b/library/Vspheredb/DbObject/TaggingCategory.php
index f6fa74a6..f60e0562 100644
--- a/library/Vspheredb/DbObject/TaggingCategory.php
+++ b/library/Vspheredb/DbObject/TaggingCategory.php
@@ -5,26 +5,28 @@
 class TaggingCategory extends BaseDbObject
 {
     public const TABLE = 'tagging_category';
-    protected $keyName = 'uuid';
-    protected $table = self::TABLE;
 
-    protected $defaultProperties = [
+    protected string|array|null $keyName = 'uuid';
+
+    protected ?string $table = self::TABLE;
+
+    protected ?array $defaultProperties = [
         'uuid'             => null,
         'vcenter_uuid'     => null,
         'id'               => null,
         'name'             => null,
         'cardinality'      => null,
         'description'      => null,
-        'associable_types' => null,
+        'associable_types' => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'uuid'             => 'uuid',
         'id'               => 'id',
         'name'             => 'name',
         'cardinality'      => 'cardinality',
         'description'      => 'description',
-        'associable_types' => 'associable_types',
+        'associable_types' => 'associable_types'
     ];
 
     public function cardinalityIsSingle(): bool
diff --git a/library/Vspheredb/DbObject/TaggingObjectTag.php b/library/Vspheredb/DbObject/TaggingObjectTag.php
index 2ff89d33..a5a28b96 100644
--- a/library/Vspheredb/DbObject/TaggingObjectTag.php
+++ b/library/Vspheredb/DbObject/TaggingObjectTag.php
@@ -6,18 +6,18 @@ class TaggingObjectTag extends BaseDbObject
 {
     public const TABLE = 'tagging_object_tag';
 
-    protected $keyName = ['object_uuid', 'tag_uuid'];
+    protected string|array|null $keyName = ['object_uuid', 'tag_uuid'];
 
-    protected $table = self::TABLE;
+    protected ?string $table = self::TABLE;
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'object_uuid'  => null,
         'tag_uuid'     => null,
-        'vcenter_uuid' => null,
+        'vcenter_uuid' => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'object_uuid' => 'object_uuid',
-        'tag_uuid'    => 'tag_uuid',
+        'tag_uuid'    => 'tag_uuid'
     ];
 }
diff --git a/library/Vspheredb/DbObject/TaggingTag.php b/library/Vspheredb/DbObject/TaggingTag.php
index aed9da1a..338b1e1f 100644
--- a/library/Vspheredb/DbObject/TaggingTag.php
+++ b/library/Vspheredb/DbObject/TaggingTag.php
@@ -6,28 +6,28 @@ class TaggingTag extends BaseDbObject
 {
     public const TABLE = 'tagging_tag';
 
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = self::TABLE;
+    protected ?string $table = self::TABLE;
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'             => null,
         'category_uuid'    => null,
         'vcenter_uuid'     => null,
         'id'               => null,
         'name'             => null,
-        'description'      => null,
+        'description'      => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'uuid'             => 'uuid',
         'category_uuid'    => 'category_uuid',
         'id'               => 'id',
         'name'             => 'name',
-        'description'      => 'description',
+        'description'      => 'description'
     ];
 
-    public static function loadAllForVCenter(VCenter $vCenter)
+    public static function loadAllForVCenter(VCenter $vCenter): array
     {
         $dummy = new static();
         $connection = $vCenter->getConnection();
diff --git a/library/Vspheredb/DbObject/VCenter.php b/library/Vspheredb/DbObject/VCenter.php
index 908ef213..b440f535 100644
--- a/library/Vspheredb/DbObject/VCenter.php
+++ b/library/Vspheredb/DbObject/VCenter.php
@@ -7,19 +7,21 @@
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
 use Ramsey\Uuid\Uuid;
 use Ramsey\Uuid\UuidInterface;
+use RuntimeException;
+use stdClass;
 
 /**
  * @method Db getConnection()
  */
 class VCenter extends BaseDbObject
 {
-    protected $table = 'vcenter';
+    protected ?string $table = 'vcenter';
 
-    protected $keyName = 'instance_uuid';
+    protected string|array|null $keyName = 'instance_uuid';
 
-    protected $autoincKeyName = 'id';
+    protected ?string $autoincKeyName = 'id';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'id'                      => null,
         'instance_uuid'           => null,
         'trust_store_id'          => null,
@@ -35,10 +37,10 @@ class VCenter extends BaseDbObject
         'license_product_name'    => null,
         'license_product_version' => null,
         'locale_build'            => null,
-        'locale_version'          => null,
+        'locale_version'          => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'instanceUuid'          => 'instance_uuid',
         'name'                  => 'api_name',
         'version'               => 'version',
@@ -51,57 +53,73 @@ class VCenter extends BaseDbObject
         'licenseProductName'    => 'license_product_name',
         'licenseProductVersion' => 'license_product_version',
         'localeBuild'           => 'locale_build',
-        'localeVersion'         => 'locale_version',
+        'localeVersion'         => 'locale_version'
     ];
 
-    public function getFullName()
+    /**
+     * @return string
+     */
+    public function getFullName(): string
     {
         return sprintf(
             '%s %s build-%s',
-            \preg_replace('/^VMware /', '', $this->get('api_name')),
+            preg_replace('/^VMware /', '', $this->get('api_name')),
             $this->get('version'),
             $this->get('build')
         );
     }
 
-    public function isHostAgent()
+    /**
+     * @return bool
+     */
+    public function isHostAgent(): bool
     {
         return $this->get('api_type') === 'HostAgent';
     }
 
-    public function isVirtualCenter()
+    /**
+     * @return bool
+     */
+    public function isVirtualCenter(): bool
     {
         return $this->get('api_type') === 'VirtualCenter';
     }
 
-    // TODO: Settle with one or the other. This should better give a UUID object
-    public function getUuid()
+
+    /**
+     * TODO: Settle with one or the other. This should better give a UUID object
+     *
+     * @return mixed
+     */
+    public function getUuid(): mixed
     {
         return $this->get('instance_uuid');
     }
 
-    public function getBinaryUuid()
+    /**
+     * @return mixed
+     */
+    public function getBinaryUuid(): mixed
     {
         return $this->get('instance_uuid');
     }
 
-    public static function loadWithUuid(string $uuid, Db $connection)
+    public static function loadWithUuid(string $uuid, Db $connection): static
     {
-        if (strlen($uuid) === 16) {
-            $uuid = Uuid::fromBytes($uuid);
-        } else {
-            $uuid = Uuid::fromString($uuid);
-        }
+        $uuid = strlen($uuid) === 16 ? Uuid::fromBytes($uuid) : Uuid::fromString($uuid);
 
         return static::load($uuid->getBytes(), $connection);
     }
 
     /**
      * @param bool $enabled
-     * @return VCenterServer
+     * @param bool $required
+     *
+     * @return ?VCenterServer
+     *
      * @throws NotFoundError
      */
-    public function getFirstServer($enabled = true, $required = true)
+    public function getFirstServer(bool $enabled = true, bool $required = true): ?VCenterServer
     {
         $db = $this->getConnection()->getDbAdapter();
         $query = $db->select()
@@ -122,49 +140,53 @@ public function getFirstServer($enabled = true, $required = true)
                     ->limit(1)
             );
             if ($serverId) {
-                throw new NotFoundError(
-                    'All server connections configured for this vCenter have been disabled'
-                );
-            } else {
-                throw new NotFoundError(
-                    'Found no server for vCenterId=' . $this->get('id')
-                );
+                throw new NotFoundError('All server connections configured for this vCenter have been disabled');
             }
+
+            throw new NotFoundError('Found no server for vCenterId=' . $this->get('id'));
         } elseif ($required) {
-            throw new NotFoundError(
-                'Found no server for vCenterId=' . $this->get('id')
-            );
-        } else {
-            return null;
+            throw new NotFoundError('Found no server for vCenterId=' . $this->get('id'));
         }
+
+        return null;
     }
 
-    public function makeBinaryGlobalUuid($moRefId)
+    /**
+     * @param mixed $moRefId
+     *
+     * @return string
+     */
+    public function makeBinaryGlobalUuid(mixed $moRefId): string
     {
-        if ($moRefId instanceof ManagedObjectReference || $moRefId instanceof \stdClass) {
+        if ($moRefId instanceof ManagedObjectReference || $moRefId instanceof stdClass) {
             return $this->makeBinaryGlobalMoRefUuid($moRefId);
-        } elseif (is_string($moRefId)) {
+        }
+
+        if (is_string($moRefId)) {
             return Uuid::uuid5(Uuid::fromBytes($this->get('uuid')), $moRefId)->getBytes();
-        } else {
-            throw new \RuntimeException('MoRef expected, got ' . gettype($moRefId));
         }
+
+        throw new RuntimeException('MoRef expected, got ' . gettype($moRefId));
     }
 
     /**
-     * @param ManagedObjectReference|\stdClass $moRef
+     * @param stdClass|ManagedObjectReference $moRef
+     *
      * @return string
      */
-    public function makeBinaryGlobalMoRefUuid($moRef): string
+    public function makeBinaryGlobalMoRefUuid(stdClass|ManagedObjectReference $moRef): string
     {
         return $this->makeBinaryGlobalMoRefUuidObject($moRef)->getBytes();
     }
 
     /**
-     * @param ManagedObjectReference|\stdClass $moRef
+     * @param stdClass|ManagedObjectReference $moRef
+     *
+     * @return UuidInterface
      */
-    public function makeBinaryGlobalMoRefUuidObject($moRef): UuidInterface
+    public function makeBinaryGlobalMoRefUuidObject(stdClass|ManagedObjectReference $moRef): UuidInterface
     {
-        if ($moRef instanceof \stdClass) {
+        if ($moRef instanceof stdClass) {
             $moRef = ManagedObjectReference::fromSerialization($moRef);
         }
 
@@ -172,14 +194,12 @@ public function makeBinaryGlobalMoRefUuidObject($moRef): UuidInterface
     }
 
     /**
-     * @param $value
+     * @param string $value
+     *
+     * @return void
      */
-    public function setInstance_uuid($value) // phpcs:ignore
+    public function setInstance_uuid(string $value): void // phpcs:ignore
     {
-        if (strlen($value) > 16) {
-            $this->reallySet('instance_uuid', Uuid::fromString($value)->getBytes());
-        } else {
-            $this->reallySet('instance_uuid', $value);
-        }
+        $this->reallySet('instance_uuid', strlen($value) > 16 ? Uuid::fromString($value)->getBytes() : $value);
     }
 }
diff --git a/library/Vspheredb/DbObject/VCenterServer.php b/library/Vspheredb/DbObject/VCenterServer.php
index 1fb12688..bb894d43 100644
--- a/library/Vspheredb/DbObject/VCenterServer.php
+++ b/library/Vspheredb/DbObject/VCenterServer.php
@@ -6,11 +6,11 @@
 
 class VCenterServer extends BaseDbObject
 {
-    protected $table = 'vcenter_server';
+    protected ?string $table = 'vcenter_server';
 
-    protected $autoincKeyName = 'id';
+    protected ?string $autoincKeyName = 'id';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'id'              => null,
         'vcenter_id'      => null,
         'scheme'          => null,
@@ -23,14 +23,15 @@ class VCenterServer extends BaseDbObject
         'proxy_pass'      => null,
         'ssl_verify_peer' => null,
         'ssl_verify_host' => null,
-        'enabled'         => null,
+        'enabled'         => null
     ];
 
     /**
      * @param Db $db
+     *
      * @return VCenterServer[]
      */
-    public static function loadEnabledServers(Db $db)
+    public static function loadEnabledServers(Db $db): array
     {
         return static::loadAll(
             $db,
diff --git a/library/Vspheredb/DbObject/VirtualMachine.php b/library/Vspheredb/DbObject/VirtualMachine.php
index 0364b221..0ad21cfc 100644
--- a/library/Vspheredb/DbObject/VirtualMachine.php
+++ b/library/Vspheredb/DbObject/VirtualMachine.php
@@ -6,16 +6,18 @@
 use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\MappedClass\GuestNicInfo;
 use Icinga\Module\Vspheredb\Util;
+use InvalidArgumentException;
+use stdClass;
 
 class VirtualMachine extends BaseDbObject
 {
     use CustomValueSupport;
 
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'virtual_machine';
+    protected ?string $table = 'virtual_machine';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'              => null,
         'vcenter_uuid'      => null,
         'annotation'        => null,
@@ -48,23 +50,23 @@ class VirtualMachine extends BaseDbObject
         'cpu_hot_add_enabled'        => null,
         'memory_hot_add_enabled'     => null,
         'guest_ip_addresses'         => null,
-        'guest_ip_stack'             => null,
+        'guest_ip_stack'             => null
     ];
 
-    protected $objectReferences = [
+    protected array $objectReferences = [
         'runtime_host_uuid',
         'resource_pool_uuid'
     ];
 
-    protected $booleanProperties = [
+    protected array $booleanProperties = [
         'template',
         'online_standby',
         'paused',
         'cpu_hot_add_enabled',
-        'memory_hot_add_enabled',
+        'memory_hot_add_enabled'
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'config.annotation'          => 'annotation',
         // TODO: Delegate to vm_hardware sync?
         'config.hardware.memoryMB'   => 'hardware_memorymb',
@@ -97,12 +99,14 @@ class VirtualMachine extends BaseDbObject
         'config.cpuHotAddEnabled'    => 'cpu_hot_add_enabled',
         'config.memoryHotAddEnabled' => 'memory_hot_add_enabled',
         // 'runtime.bootTime' => 'runtime_last_boot_time',
-        // 'runtime.suspendTime' 'runtime_last_suspend_time',
+        // 'runtime.suspendTime' 'runtime_last_suspend_time'
     ];
 
-    /** @var ?HostSystem */
-    protected $runtimeHost = null;
+    protected ?HostSystem $runtimeHost = null;
 
+    /**
+     * @return bool
+     */
     public function hasRuntimeHost(): bool
     {
         return $this->get('runtime_host_uuid') !== null;
@@ -110,7 +114,8 @@ public function hasRuntimeHost(): bool
 
     /**
      * @return HostSystem
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @throws NotFoundError
      */
     public function getRuntimeHost(): HostSystem
     {
@@ -122,11 +127,7 @@ public function getRuntimeHost(): HostSystem
             $this->runtimeHost = null;
         }
 
-        if ($this->runtimeHost === null) {
-            $this->runtimeHost = HostSystem::load($uuid, $this->connection);
-        }
-
-        return $this->runtimeHost;
+        return $this->runtimeHost ??= HostSystem::load($uuid, $this->connection);
     }
 
     /**
@@ -135,18 +136,22 @@ public function getRuntimeHost(): HostSystem
      * Can be used to avoid duplicate loading of the very same host. As of this
      * writing, this does NOT change VM properties.
      *
-     * @param HostSystem|null $host
+     * @param ?HostSystem $host
+     *
      * @return void
+     *
+     * @throws InvalidArgumentException
      */
-    public function setRuntimeHost(?HostSystem $host)
+    public function setRuntimeHost(?HostSystem $host): void
     {
         if ($host === null) {
             $this->runtimeHost = null;
+
             return;
         }
 
         if ($host->get('uuid') !== $this->get('runtime_host_uuid')) {
-            throw new \InvalidArgumentException(sprintf(
+            throw new InvalidArgumentException(sprintf(
                 'Cannot set runtime host with UUID %s, expected %s',
                 Util::niceUuid($host->get('uuid')),
                 Util::niceUuid($this->get('runtime_host_uuid'))
@@ -157,15 +162,14 @@ public function setRuntimeHost(?HostSystem $host)
     }
 
     /**
-     * @param $value
+     * @param string|bool|null $value
+     *
      * @return $this
      */
-    public function setPaused($value)
+    public function setPaused(string|bool|null $value): static
     {
         // powered off?
-        if ($value === null) {
-            $value = 'n';
-        }
+        $value ??= 'n';
 
         if (is_bool($value)) {
             $value = DbProperty::booleanToDb($value);
@@ -206,11 +210,16 @@ public function setPaused($value)
      *     'netBIOSConfig' => NULL,
      *     'network' => 'Demo LAN',
      *  }]
+     *
+     * @param ?object $value
+     *
+     * @return void
      */
-    public function setNet($value)
+    public function setNet(?object $value): void
     {
         if ($value === null || ! isset($value->GuestNicInfo)) {
             $this->set('guest_ip_addresses', null);
+
             return;
         }
         $addresses = [];
@@ -221,7 +230,7 @@ public function setNet($value)
                 $addresses[$key] = (object) [
                     'connected' => $nic->connected,
                     'network'   => $nic->network,
-                    'addresses' => [],
+                    'addresses' => []
                 ];
             }
 
@@ -242,7 +251,7 @@ public function setNet($value)
                         // * tentative    Indicates that the uniqueness of the address on the link
                         //                is presently being verified
                         // * unknown      Indicates that the status cannot be determined
-                        'state'        => property_exists($config, 'state') ? $config->state : null,
+                        'state'        => property_exists($config, 'state') ? $config->state : null
                     ];
                 }
             }
@@ -251,7 +260,12 @@ public function setNet($value)
         $this->set('guest_ip_addresses', JsonString::encode((object) $addresses));
     }
 
-    public function setGuestIpStack($value)
+    /**
+     * @param ?object $value
+     *
+     * @return void
+     */
+    public function setGuestIpStack(?object $value): void
     {
         if ($value === null) {
             $this->set('guest_ip_stack', null);
@@ -316,6 +330,8 @@ public function setGuestIpStack($value)
      *     }]
      *   }
      * }]
+     *
+     * @return ?array
      */
     public function guestIpStack(): ?array
     {
@@ -327,7 +343,10 @@ public function guestIpStack(): ?array
         return JsonString::decode($value);
     }
 
-    public function guestIpAddresses(): \stdClass
+    /**
+     * @return stdClass
+     */
+    public function guestIpAddresses(): stdClass
     {
         $value = $this->get('guest_ip_addresses');
         if ($value === null) {
@@ -338,18 +357,17 @@ public function guestIpAddresses(): \stdClass
     }
 
     /**
-     * @param $value
+     * @param ?object $value
      */
-    protected function setBootOptions($value)
+    protected function setBootOptions(?object $value): void
     {
         if ($value === null) {
             return;
         }
-        if (property_exists($value, 'networkBootProtocol')) {
-            $this->set('boot_network_protocol', $value->networkBootProtocol);
-        } else {
-            $this->set('boot_network_protocol', null);
-        }
+        $this->set(
+            'boot_network_protocol',
+            property_exists($value, 'networkBootProtocol') ? $value->networkBootProtocol : null
+        );
 
         // bootOrder might be missing, should then default to disk, net
         if (property_exists($value, 'bootOrder')) {
diff --git a/library/Vspheredb/DbObject/VmDatastoreUsage.php b/library/Vspheredb/DbObject/VmDatastoreUsage.php
index df11618c..342450b5 100644
--- a/library/Vspheredb/DbObject/VmDatastoreUsage.php
+++ b/library/Vspheredb/DbObject/VmDatastoreUsage.php
@@ -6,25 +6,26 @@
 
 class VmDatastoreUsage extends DbObject
 {
-    protected $keyName = ['vm_uuid', 'datastore_uuid'];
+    protected string|array|null $keyName = ['vm_uuid', 'datastore_uuid'];
 
-    protected $table = 'vm_datastore_usage';
+    protected ?string $table = 'vm_datastore_usage';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'vm_uuid'        => null,
         'datastore_uuid' => null,
         'vcenter_uuid'   => null,
         'committed'      => null,
         'uncommitted'    => null,
         'unshared'       => null,
-        'ts_updated'     => null,
+        'ts_updated'     => null
     ];
 
     /**
      * @param VCenter $vCenter
+     *
      * @return static[]
      */
-    public static function loadAllForVCenter(VCenter $vCenter)
+    public static function loadAllForVCenter(VCenter $vCenter): array
     {
         $dummy = new static();
         $objects = static::loadAll(
diff --git a/library/Vspheredb/DbObject/VmDisk.php b/library/Vspheredb/DbObject/VmDisk.php
index ee325da8..a816ad91 100644
--- a/library/Vspheredb/DbObject/VmDisk.php
+++ b/library/Vspheredb/DbObject/VmDisk.php
@@ -6,9 +6,9 @@
 
 class VmDisk extends BaseVmHardwareDbObject
 {
-    protected $table = 'vm_disk';
+    protected ?string $table = 'vm_disk';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'vm_uuid'          => null,
         'hardware_key'     => null,
         'disk_uuid'        => null,
@@ -19,20 +19,20 @@ class VmDisk extends BaseVmHardwareDbObject
         'split'            => null,
         'write_through'    => null,
         'thin_provisioned' => null,
-        'vcenter_uuid'     => null,
+        'vcenter_uuid'     => null
     ];
 
-    protected $objectReferences = [
-        'datastore_uuid',
+    protected array $objectReferences = [
+        'datastore_uuid'
     ];
 
-    protected $booleanProperties = [
+    protected array $booleanProperties = [
         'split',
         'write_through',
-        'thin_provisioned',
+        'thin_provisioned'
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         // 'backing.contentId' => 'content_id', // to binary, b82d1a823ecedaeece267061396dac9f
         'backing.uuid'        => 'disk_uuid', // to binary, 6000C299-5ba6-c2cf-1706-3ba11a5d1df0
         'backing.datastore._' => 'datastore_uuid', // make binary unique
@@ -46,10 +46,11 @@ class VmDisk extends BaseVmHardwareDbObject
     ];
 
     /**
-     * @param $value
+     * @param ?string $value
+     *
      * @return VmDisk
      */
-    public function setDisk_uuid($value) // phpcs:ignore
+    public function setDisk_uuid(?string $value): VmDisk // phpcs:ignore
     {
         if ($value !== null && strlen($value) > 16) {
             $value = Uuid::fromString($value)->getBytes();
diff --git a/library/Vspheredb/DbObject/VmDiskUsage.php b/library/Vspheredb/DbObject/VmDiskUsage.php
index 92c7aaeb..76ef787c 100644
--- a/library/Vspheredb/DbObject/VmDiskUsage.php
+++ b/library/Vspheredb/DbObject/VmDiskUsage.php
@@ -6,23 +6,24 @@
 
 class VmDiskUsage extends DbObject
 {
-    protected $keyName = ['vm_uuid', 'disk_path'];
+    protected string|array|null $keyName = ['vm_uuid', 'disk_path'];
 
-    protected $table = 'vm_disk_usage';
+    protected ?string $table = 'vm_disk_usage';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'vm_uuid'      => null,
         'disk_path'    => null,
         'capacity'     => null,
         'free_space'   => null,
-        'vcenter_uuid' => null,
+        'vcenter_uuid' => null
     ];
 
     /**
      * @param VCenter $vCenter
+     *
      * @return static[]
      */
-    public static function loadAllForVCenter(VCenter $vCenter)
+    public static function loadAllForVCenter(VCenter $vCenter): array
     {
         $dummy = new static();
         $objects = static::loadAll(
diff --git a/library/Vspheredb/DbObject/VmHardware.php b/library/Vspheredb/DbObject/VmHardware.php
index e24e4fdb..dcce8d01 100644
--- a/library/Vspheredb/DbObject/VmHardware.php
+++ b/library/Vspheredb/DbObject/VmHardware.php
@@ -4,9 +4,9 @@
 
 class VmHardware extends BaseVmHardwareDbObject
 {
-    protected $table = 'vm_hardware';
+    protected ?string $table = 'vm_hardware';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'vm_uuid'        => null,
         'hardware_key'   => null,
         'bus_number'     => null,
@@ -14,18 +14,18 @@ class VmHardware extends BaseVmHardwareDbObject
         'controller_key' => null,
         'label'          => null,
         'summary'        => null,
-        'vcenter_uuid'   => null,
+        'vcenter_uuid'   => null
     ];
 
-    protected $objectReferences = [
-        'vm_uuid',
+    protected array $objectReferences = [
+        'vm_uuid'
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'deviceInfo.label'   => 'label',
         'deviceInfo.summary' => 'summary',
         'busNumber'          => 'bus_number',
         'unitNumber'         => 'unit_number',
-        'controllerKey'      => 'controller_key',
+        'controllerKey'      => 'controller_key'
     ];
 }
diff --git a/library/Vspheredb/DbObject/VmNetworkAdapter.php b/library/Vspheredb/DbObject/VmNetworkAdapter.php
index bfab1e04..4d96e77e 100644
--- a/library/Vspheredb/DbObject/VmNetworkAdapter.php
+++ b/library/Vspheredb/DbObject/VmNetworkAdapter.php
@@ -4,26 +4,26 @@
 
 class VmNetworkAdapter extends BaseVmHardwareDbObject
 {
-    protected $table = 'vm_network_adapter';
+    protected ?string $table = 'vm_network_adapter';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'vm_uuid'        => null,
         'hardware_key'   => null,
         'portgroup_uuid' => null,
         'port_key'       => null,
         'mac_address'    => null,
         'address_type'   => null,
-        'vcenter_uuid'   => null,
+        'vcenter_uuid'   => null
     ];
 
-    protected $objectReferences = [
-        'portgroup_uuid',
+    protected array $objectReferences = [
+        'portgroup_uuid'
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'backing.port.portgroupKey' => 'portgroup_uuid',
         'backing.port.portKey'      => 'port_key',
         'macAddress'                => 'mac_address', // binary(6)? new xxeuid?
-        'addressType'               => 'address_type',
+        'addressType'               => 'address_type'
     ];
 }
diff --git a/library/Vspheredb/DbObject/VmQuickStats.php b/library/Vspheredb/DbObject/VmQuickStats.php
index 165ce8cc..5bb1f9a1 100644
--- a/library/Vspheredb/DbObject/VmQuickStats.php
+++ b/library/Vspheredb/DbObject/VmQuickStats.php
@@ -6,11 +6,11 @@
 
 class VmQuickStats extends BaseDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'vm_quick_stats';
+    protected ?string $table = 'vm_quick_stats';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'                              => null,
         'ballooned_memory_mb'               => null,
         'compressed_memory_kb'              => null,
@@ -32,10 +32,10 @@ class VmQuickStats extends BaseDbObject
         'static_memory_entitlement_mb'      => null,
         'swapped_memory_mb'                 => null,
         'uptime'                            => null,
-        'vcenter_uuid'                      => null,
+        'vcenter_uuid'                      => null
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'summary.quickStats.balloonedMemory'              => 'ballooned_memory_mb',
         'summary.quickStats.compressedMemory'             => 'compressed_memory_kb',
         'summary.quickStats.consumedOverheadMemory'       => 'consumed_overhead_memory_mb',
@@ -55,17 +55,26 @@ class VmQuickStats extends BaseDbObject
         'summary.quickStats.staticCpuEntitlement'         => 'static_cpu_entitlement',
         'summary.quickStats.staticMemoryEntitlement'      => 'static_memory_entitlement_mb',
         'summary.quickStats.swappedMemory'                => 'swapped_memory_mb',
-        'summary.quickStats.uptimeSeconds'                => 'uptime',
+        'summary.quickStats.uptimeSeconds'                => 'uptime'
     ];
 
-    protected static $preloadCache = null;
+    /** @var ?static[] */
+    protected static ?array $preloadCache = null;
 
-    public static function preloadAll(Db $db)
+    /**
+     * @param Db $db
+     *
+     * @return void
+     */
+    public static function preloadAll(Db $db): void
     {
         self::$preloadCache = self::loadAll($db, null, 'uuid');
     }
 
-    public static function clearPreloadCache()
+    /**
+     * @return void
+     */
+    public static function clearPreloadCache(): void
     {
         self::$preloadCache = null;
     }
@@ -73,10 +82,14 @@ public static function clearPreloadCache()
     /**
      * Valid are values from 0 to max allowed memory, but I've met -1 on an
      * ESXi host in the wild (6.7)
+     *
+     * @param int $value
+     *
+     * @return static
      */
-    public function setHost_memory_usage_mb($value) // phpcs:ignore
+    public function setHost_memory_usage_mb(int $value): static // phpcs:ignore
     {
-        if ((int) $value === -1) {
+        if ($value === -1) {
             $value = null;
         }
 
@@ -85,7 +98,12 @@ public function setHost_memory_usage_mb($value) // phpcs:ignore
         return $this;
     }
 
-    public static function loadFor(VirtualMachine $object)
+    /**
+     * @param VirtualMachine $object
+     *
+     * @return VmQuickStats|mixed|static
+     */
+    public static function loadFor(VirtualMachine $object): mixed
     {
         if ($object->hasBeenLoadedFromDb()) {
             $connection = $object->getConnection();
@@ -105,7 +123,12 @@ public static function loadFor(VirtualMachine $object)
         return static::create();
     }
 
-    protected function setUptime($value)
+    /**
+     * @param int $value
+     *
+     * @return VmQuickStats
+     */
+    protected function setUptime(int $value): VmQuickStats
     {
         if ($value === 0) {
             $value = null;
diff --git a/library/Vspheredb/DbObject/VmSnapshot.php b/library/Vspheredb/DbObject/VmSnapshot.php
index 934263b2..780288c7 100644
--- a/library/Vspheredb/DbObject/VmSnapshot.php
+++ b/library/Vspheredb/DbObject/VmSnapshot.php
@@ -4,11 +4,11 @@
 
 class VmSnapshot extends BaseDbObject
 {
-    protected $keyName = 'uuid';
+    protected string|array|null $keyName = 'uuid';
 
-    protected $table = 'vm_snapshot';
+    protected ?string $table = 'vm_snapshot';
 
-    protected $defaultProperties = [
+    protected ?array $defaultProperties = [
         'uuid'            => null,
         'parent_uuid'      => null,
         'vm_uuid'          => null,
@@ -19,24 +19,24 @@ class VmSnapshot extends BaseDbObject
         'ts_create'        => null,
         'state'            => null,
         'quiesced'         => null,
-        'vcenter_uuid'     => null,
+        'vcenter_uuid'     => null
     ];
 
-    protected $objectReferences = [
+    protected array $objectReferences = [
         'vm_uuid',
-        'parent_uuid',
+        'parent_uuid'
     ];
 
-    protected $booleanProperties = [
+    protected array $booleanProperties = [
         'quiesced',
-        'replay_supported',
+        'replay_supported'
     ];
 
-    protected $dateTimeProperties = [
-        'ts_create',
+    protected array $dateTimeProperties = [
+        'ts_create'
     ];
 
-    protected $propertyMap = [
+    protected array $propertyMap = [
         'id'              => 'id',
         'name'            => 'name',
         'description'     => 'description',
@@ -44,6 +44,6 @@ class VmSnapshot extends BaseDbObject
         'quiesced'        => 'quiesced',
         'createTime'      => 'ts_create',
         'vm'              => 'vm_uuid',
-        'parent'          => 'parent_uuid',
+        'parent'          => 'parent_uuid'
     ];
 }
diff --git a/library/Vspheredb/EventHistory/VmRecentMigrationHistory.php b/library/Vspheredb/EventHistory/VmRecentMigrationHistory.php
index 86a45198..6e634987 100644
--- a/library/Vspheredb/EventHistory/VmRecentMigrationHistory.php
+++ b/library/Vspheredb/EventHistory/VmRecentMigrationHistory.php
@@ -4,19 +4,26 @@
 
 use Icinga\Module\Vspheredb\Db\DbUtil;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
+use Zend_Db_Adapter_Abstract;
 
 class VmRecentMigrationHistory
 {
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
 
+    /**
+     * @param VirtualMachine $vm
+     */
     public function __construct(VirtualMachine $vm)
     {
         $this->vm = $vm;
         $this->db = $vm->getConnection()->getDbAdapter();
     }
 
+    /**
+     * @return int
+     */
     public function countWeeklyMigrationAttempts(): int
     {
         $query = $this->db->select()
diff --git a/library/Vspheredb/Exception/NoPermissionException.php b/library/Vspheredb/Exception/NoPermissionException.php
index 581588a2..7843eb44 100644
--- a/library/Vspheredb/Exception/NoPermissionException.php
+++ b/library/Vspheredb/Exception/NoPermissionException.php
@@ -4,5 +4,5 @@
 
 class NoPermissionException extends VmwareException
 {
-    public $paths;
+    public ?array $paths = null;
 }
diff --git a/library/Vspheredb/Exception/NotAuthenticatedException.php b/library/Vspheredb/Exception/NotAuthenticatedException.php
index 9eabd6a4..a862698f 100644
--- a/library/Vspheredb/Exception/NotAuthenticatedException.php
+++ b/library/Vspheredb/Exception/NotAuthenticatedException.php
@@ -4,5 +4,5 @@
 
 class NotAuthenticatedException extends VmwareException
 {
-    public $paths;
+    public ?array $paths = null;
 }
diff --git a/library/Vspheredb/Exception/VmwareException.php b/library/Vspheredb/Exception/VmwareException.php
index 8567e9ab..9cba14c1 100644
--- a/library/Vspheredb/Exception/VmwareException.php
+++ b/library/Vspheredb/Exception/VmwareException.php
@@ -4,6 +4,7 @@
 
 use Exception;
 use Icinga\Module\Vspheredb\MappedClass\MissingProperty;
+use RuntimeException;
 
 class VmwareException extends Exception
 {
@@ -12,11 +13,13 @@ class VmwareException extends Exception
 
     /**
      * @param MissingProperty[] $missingSet
+     *
+     * @return VmwareException|RuntimeException
      */
-    public static function forMissingSet($missingSet)
+    public static function forMissingSet(array $missingSet): VmwareException|RuntimeException
     {
         if (empty($missingSet)) {
-            return new \RuntimeException('Trying to create an Exception for an empty missing set');
+            return new RuntimeException('Trying to create an Exception for an empty missing set');
         }
         $paths = [];
         foreach ($missingSet as $missingProperty) {
diff --git a/library/Vspheredb/Format.php b/library/Vspheredb/Format.php
index b61987b8..78a42a94 100644
--- a/library/Vspheredb/Format.php
+++ b/library/Vspheredb/Format.php
@@ -4,7 +4,7 @@
 
 class Format
 {
-    public static function bytes($value): string
+    public static function bytes(float|int $value): string
     {
         $base = 1024;
         $units = ['B', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB'];
@@ -30,52 +30,45 @@ public static function bytes($value): string
         return sprintf('%s%s %s', $sign, $output, $units[$pow]);
     }
 
-    public static function mBytes($value): string
+    public static function mBytes(float|int|null $value): string
     {
         return static::bytes($value * 1024 * 1024);
     }
 
-    public static function linkSpeedMb($mb): string
+    public static function linkSpeedMb(int $mb): string
     {
-        if ($mb >= 1000000) {
-            return sprintf('%.3G TBit/s', $mb / 1000000);
-        } elseif ($mb >= 1000) {
-            return sprintf('%.3G GBit/s', $mb / 1000);
-        } else {
-            return sprintf('%.3G MBit/s', $mb);
-        }
+        return match (true) {
+            $mb >= 1000000 => sprintf('%.3G TBit/s', $mb / 1000000),
+            $mb >= 1000    => sprintf('%.3G GBit/s', $mb / 1000),
+            default        => sprintf('%.3G MBit/s', $mb)
+        };
     }
 
-    public static function mhz($mhz): string
+    public static function mhz(?int $mhz): string
     {
         if ($mhz === null) {
             return '-';
         }
         $sign = $mhz < 0 ? '-' : '';
         $mhz = abs($mhz);
-        if ($mhz >= 1000000) {
-            return $sign . sprintf('%.3G THz', $mhz / 1000000);
-        } elseif ($mhz >= 1000) {
-            return $sign . sprintf('%.3G GHz', $mhz / 1000);
-        } else {
-            return $sign . sprintf('%.3G MHz', $mhz);
-        }
+
+        return $sign . match (true) {
+            $mhz >= 1000000 => sprintf('%.3G THz', $mhz / 1000000),
+            $mhz >= 1000    => sprintf('%.3G GHz', $mhz / 1000),
+            default         => sprintf('%.3G MHz', $mhz)
+        };
     }
 
     public static function mhzWithSeparateUnit($mhz): array
     {
         $sign = $mhz < 0 ? '-' : '';
         $mhz = abs($mhz);
-        if ($mhz > 1000000) {
-            $unit = 'THz';
-            $value = $mhz / 1000000;
-        } elseif ($mhz > 1000) {
-            $unit = 'GHz';
-            $value = $mhz / 1000;
-        } else {
-            $unit = 'MHz';
-            $value = $mhz;
-        }
+
+        [$unit, $value] = match (true) {
+            $mhz >= 1000000 => ['THz', $mhz / 1000000],
+            $mhz >= 1000    => ['GHz', $mhz / 1000],
+            default         => ['MHz', $mhz]
+        };
 
         return [$sign . sprintf('%.3G', $value), $unit];
     }
diff --git a/library/Vspheredb/Hint/ConnectionStateDetails.php b/library/Vspheredb/Hint/ConnectionStateDetails.php
index 26532134..bb055a4d 100644
--- a/library/Vspheredb/Hint/ConnectionStateDetails.php
+++ b/library/Vspheredb/Hint/ConnectionStateDetails.php
@@ -8,16 +8,26 @@ class ConnectionStateDetails
 {
     use Translation;
 
-    protected static $instance;
+    protected static ?ConnectionStateDetails $instance = null;
 
-    public static function getFor($state)
+    /**
+     * @param string $state
+     *
+     * @return ?string
+     */
+    public static function getFor(string $state): ?string
     {
         return static::instance()->getConnectionStateDetails($state);
     }
 
-    protected function getConnectionStateDetails($state)
+    /**
+     * @param string $state
+     *
+     * @return ?string
+     */
+    protected function getConnectionStateDetails(string $state): ?string
     {
-        $infos = [
+        return match ($state) {
             'connected'    => $this->translate(
                 'The server has access to the virtual machine'
             ),
@@ -31,27 +41,26 @@ protected function getConnectionStateDetails($state)
                 . ' failures. In this case, no configuration can be returned for'
                 . ' a virtual machine'
             ),
-            'invalid' => $this->translate(
+            'invalid'      => $this->translate(
                 'The virtual machine configuration format is invalid. Thus, it is'
                 . ' accessible on disk, but corrupted in a way that does not allow'
                 . ' the server to read the content. In this case, no configuration'
                 . ' can be returned for a virtual machine.'
             ),
-            'orphaned' => $this->translate(
+            'orphaned'     => $this->translate(
                 'The virtual machine is no longer registered on the host it is'
                 . ' associated with. For example, a virtual machine that is'
                 . ' unregistered or deleted directly on a host managed by'
                 . ' VirtualCenter shows up in this state.'
             ),
-        ];
-
-        return $infos[$state ?? ''];
+            default        => null
+        };
     }
 
     /**
-     * @return self
+     * @return static
      */
-    protected static function instance()
+    protected static function instance(): ConnectionStateDetails
     {
         if (static::$instance === null) {
             static::$instance = new static();
diff --git a/library/Vspheredb/Hook/AnonymizerHook.php b/library/Vspheredb/Hook/AnonymizerHook.php
index 5d1fd4a8..7c29874f 100644
--- a/library/Vspheredb/Hook/AnonymizerHook.php
+++ b/library/Vspheredb/Hook/AnonymizerHook.php
@@ -4,7 +4,17 @@
 
 abstract class AnonymizerHook
 {
+    /**
+     * @param ?string $string
+     *
+     * @return ?string
+     */
     abstract public function anonymizeString(?string $string): ?string;
 
+    /**
+     * @param ?string $string
+     *
+     * @return ?string
+     */
     abstract public function shuffleString(?string $string): ?string;
 }
diff --git a/library/Vspheredb/Hook/PerfDataConsumerHook.php b/library/Vspheredb/Hook/PerfDataConsumerHook.php
index 6d41fc79..53b17ae4 100644
--- a/library/Vspheredb/Hook/PerfDataConsumerHook.php
+++ b/library/Vspheredb/Hook/PerfDataConsumerHook.php
@@ -4,9 +4,9 @@
 
 use gipfl\InfluxDb\DataPoint;
 use gipfl\Web\Form;
+use Icinga\Application\Hook;
 use Icinga\Module\Vspheredb\Daemon\RemoteClient;
 use Icinga\Module\Vspheredb\Storable\PerfdataConsumer;
-use Icinga\Web\Hook;
 use InvalidArgumentException;
 use Psr\Log\LoggerAwareInterface;
 use Psr\Log\LoggerAwareTrait;
@@ -21,26 +21,41 @@ abstract class PerfDataConsumerHook implements LoggerAwareInterface
 {
     use LoggerAwareTrait;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
-    protected $settings = [];
+    protected array $settings = [];
 
-    protected $queue;
+    protected array $queue = [];
 
-    public static function initialize(LoopInterface $loop, $settings = [])
+    /**
+     * @param LoopInterface $loop
+     * @param array|object $settings
+     *
+     * @return $this
+     */
+    public static function initialize(LoopInterface $loop, array|object $settings = []): static
     {
         return (new static())->setLoop($loop)->setSettings($settings);
     }
 
-    public function setLoop(LoopInterface $loop)
+    /**
+     * @param LoopInterface $loop
+     *
+     * @return $this
+     */
+    public function setLoop(LoopInterface $loop): static
     {
         $this->loop = $loop;
 
         return $this;
     }
 
-    public function setSettings($settings)
+    /**
+     * @param array|object $settings
+     *
+     * @return $this
+     */
+    public function setSettings(array|object $settings): static
     {
         $this->settings = (array) $settings;
 
@@ -49,47 +64,65 @@ public function setSettings($settings)
 
     /**
      * @param string $name
+     * @param mixed $default
+     *
+     * @return mixed
      */
-    public function getSetting(string $name, $default = null)
+    public function getSetting(string $name, mixed $default = null): mixed
     {
         if (array_key_exists($name, $this->settings)) {
             return $this->settings[$name];
-        } else {
-            return $default;
         }
+
+        return $default;
     }
 
     /**
      * @return string
      */
-    public static function getName()
+    public static function getName(): string
     {
         return preg_replace('/Hook$/', '', static::getClassBaseName(get_called_class()));
     }
 
     /**
+     * @param RemoteClient $client
+     *
      * @return Form
      */
-    abstract public function getConfigurationForm(RemoteClient $client);
+    abstract public function getConfigurationForm(RemoteClient $client): Form;
 
+    /**
+     * @param RemoteClient $client
+     *
+     * @return Form
+     */
     public function getSubscriptionForm(RemoteClient $client)
     {
         return null;
     }
 
-    public static function createConsumerInstance(PerfdataConsumer $consumer, LoopInterface $loop)
+    /**
+     * @param PerfdataConsumer $consumer
+     * @param LoopInterface $loop
+     *
+     * @return static
+     */
+    public static function createConsumerInstance(PerfdataConsumer $consumer, LoopInterface $loop): static
     {
         $class = static::getClass($consumer->get('implementation'));
-        /** @var PerfDataConsumerHook $instance */
+
         return $class::initialize($loop, $consumer->settings());
     }
 
     /**
      * Hint: Currently unused
      *
-     * @var DataPoint[] $points
+     * @param DataPoint[] $points
+     *
+     * @return void
      */
-    public function pushDataPoints($points)
+    public function pushDataPoints(array $points): void
     {
         if (empty($this->queue)) {
             $this->queue[] = $points;
@@ -107,34 +140,35 @@ public function pushDataPoints($points)
      *
      * @return bool
      */
-    protected function processQueue()
+    protected function processQueue(): bool
     {
         array_pop($this->queue);
+
         return true;
     }
 
-    public static function enum()
+    /**
+     * @return array<string, string>
+     */
+    public static function enum(): array
     {
         $enum = [];
         /** @var static $instance */
         foreach (Hook::all('vspheredb/PerfDataConsumer') as $class => $instance) {
             $module = static::getModuleFromClassName($class);
             $idx = $instance::getName();
-            if ($module === 'vspheredb') {
-                $enum[$idx] = $idx;
-            } else {
-                $enum[$idx] = "$idx ($module)";
-            }
+            $enum[$idx] = $idx . ($module === 'vspheredb' ? '' : " ($module)");
         }
 
         return $enum;
     }
 
     /**
-     * @param $name
-     * @return string|null|static
+     * @param string $name
+     *
+     * @return ?string
      */
-    public static function getClass($name)
+    public static function getClass(string $name): ?string
     {
         // TODO: module/Name for foreign ones?
         /** @var static $instance */
@@ -147,18 +181,29 @@ public static function getClass($name)
         return null;
     }
 
-    protected static function getClassBaseName($class)
+    /**
+     * @param string $class
+     *
+     * @return ?string
+     */
+    protected static function getClassBaseName(string $class): ?string
     {
-        $parts = \explode('\\', $class);
+        $parts = explode('\\', $class);
+
         return array_pop($parts);
     }
 
-    protected static function getModuleFromClassName($class)
+    /**
+     * @param string $class
+     *
+     * @return string
+     */
+    protected static function getModuleFromClassName(string $class): string
     {
-        $parts = \explode('\\', ltrim($class, '\\'));
+        $parts = explode('\\', ltrim($class, '\\'));
         if (count($parts) >= 3) {
             if ($parts[0] === 'Icinga' && $parts[1] === 'Module') {
-                return \lcfirst($parts[2]);
+                return lcfirst($parts[2]);
             }
         }
 
diff --git a/library/Vspheredb/Ido.php b/library/Vspheredb/Ido.php
index 9d0b3bf6..e448f707 100644
--- a/library/Vspheredb/Ido.php
+++ b/library/Vspheredb/Ido.php
@@ -4,17 +4,17 @@
 
 use Icinga\Data\Db\DbConnection;
 use Icinga\Data\ResourceFactory;
+use Zend_Db_Adapter_Abstract;
 
 class Ido
 {
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected ?Zend_Db_Adapter_Abstract $db = null;
 
     protected function __construct()
     {
     }
 
-    public static function createByResourceName($name)
+    public static function createByResourceName(string $name): static
     {
         $self = new static();
         /** @var DbConnection $resource */
@@ -24,66 +24,61 @@ public static function createByResourceName($name)
         return $self;
     }
 
-    public function isAvailable()
+    public function isAvailable(): bool
     {
         // TODO: check program state
         return $this->db !== null;
     }
 
-    public function getAllHostStates()
+    public function getAllHostStates(): ?array
     {
-        $query = $this->db->select()->from(
-            ['o' => 'icinga_objects'],
-            [
+        $query = $this->db->select()
+            ->from(['o' => 'icinga_objects'], [
                 'host_name'       => 'o.name1',
                 'current_state'   => "(CASE WHEN has_been_checked = 1 THEN"
                     . " CASE hs.current_state WHEN 0 THEN 'UP' WHEN 1 THEN 'DOWN'"
                     . " WHEN 2 THEN 'UNREACHABLE' END"
                     . " ELSE 'PENDING' END)",
                 'is_in_downtime'  => "(CASE WHEN hs.scheduled_downtime_depth > 0 THEN 'y' ELSE 'n' END)",
-                'is_acknowledged' => "(CASE WHEN hs.problem_has_been_acknowledged = 1 THEN 'y' ELSE 'n' END)",
-            ]
-        )->join(
-            ['hs' => 'icinga_hoststatus'],
-            'o.object_id = hs.host_object_id',
-            []
-        )->where('o.is_active = 1');
+                'is_acknowledged' => "(CASE WHEN hs.problem_has_been_acknowledged = 1 THEN 'y' ELSE 'n' END)"
+            ])
+            ->join(['hs' => 'icinga_hoststatus'], 'o.object_id = hs.host_object_id', [])
+            ->where('o.is_active = 1');
 
         return $this->db->fetchAll($query);
     }
 
-    public function hasHost($hostname)
+    public function hasHost(?string $hostname): bool
     {
         if (null === $hostname) {
             return false;
         }
 
-        return $this->db->fetchOne(
-            $this->db->select()->from('icinga_objects', [
-                'host_name' => 'name1',
-            ])->where('name1 = ? AND is_active = 1 AND objecttype_id = 1', $hostname)
-        ) === $hostname;
+        return $hostname === $this->db->fetchOne(
+            $this->db->select()
+                ->from('icinga_objects', ['host_name' => 'name1'])
+                ->where('name1 = ? AND is_active = 1 AND objecttype_id = 1', $hostname)
+        );
     }
 
-    public function getHostState($hostname)
+    public function getHostState(string $hostname)
     {
-        $query = $this->db->select()->from(
-            ['o' => 'icinga_objects'],
-            [
-                'host_name'       => 'o.name1',
-                'current_state'   => "(CASE WHEN has_been_checked = 1 THEN"
-                    . " CASE hs.current_state WHEN 0 THEN 'UP' WHEN 1 THEN 'DOWN'"
-                    . " WHEN 2 THEN 'UNREACHABLE' END"
-                    . " ELSE 'PENDING' END)",
-                'is_in_downtime'  => "(CASE WHEN hs.scheduled_downtime_depth > 0 THEN 'y' ELSE 'n' END)",
-                'is_acknowledged' => "(CASE WHEN hs.problem_has_been_acknowledged = 1 THEN 'y' ELSE 'n' END)",
-                'output'          => "hs.output",
-            ]
-        )->join(
-            ['hs' => 'icinga_hoststatus'],
-            'o.object_id = hs.host_object_id',
-            []
-        )->where('name1 = ? AND is_active = 1 AND objecttype_id = 1', $hostname);
+        $query = $this->db->select()
+            ->from(
+                ['o' => 'icinga_objects'],
+                [
+                    'host_name'       => 'o.name1',
+                    'current_state'   => "(CASE WHEN has_been_checked = 1 THEN"
+                        . " CASE hs.current_state WHEN 0 THEN 'UP' WHEN 1 THEN 'DOWN'"
+                        . " WHEN 2 THEN 'UNREACHABLE' END"
+                        . " ELSE 'PENDING' END)",
+                    'is_in_downtime'  => "(CASE WHEN hs.scheduled_downtime_depth > 0 THEN 'y' ELSE 'n' END)",
+                    'is_acknowledged' => "(CASE WHEN hs.problem_has_been_acknowledged = 1 THEN 'y' ELSE 'n' END)",
+                    'output'          => "hs.output"
+                ]
+            )
+            ->join(['hs' => 'icinga_hoststatus'], 'o.object_id = hs.host_object_id', [])
+            ->where('name1 = ? AND is_active = 1 AND objecttype_id = 1', $hostname);
 
         return $this->db->fetchRow($query);
     }
diff --git a/library/Vspheredb/MappedClass/AboutInfo.php b/library/Vspheredb/MappedClass/AboutInfo.php
index 88e958b4..31f48a67 100644
--- a/library/Vspheredb/MappedClass/AboutInfo.php
+++ b/library/Vspheredb/MappedClass/AboutInfo.php
@@ -2,13 +2,15 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * AboutInfo
  *
  * This data object type describes system information including the name, type,
  * version, and build number.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class AboutInfo
 {
     /**
@@ -41,24 +43,24 @@ class AboutInfo
     /** @var string The complete product name, including the version information. */
     public $fullName;
 
-    /** @var string|null A globally unique identifier associated with this service instance */
+    /** @var ?string A globally unique identifier associated with this service instance */
     public $instanceUuid;
 
-    /** @var string|null The license product name */
+    /** @var ?string The license product name */
     public $licenseProductName;
 
-    /** @var string|null The license product version */
+    /** @var ?string The license product version */
     public $licenseProductVersion;
 
     /**
      * Build number for the current session's locale. Typically, this is a small
      * number reflecting a localization change from the normal product build.
      *
-     * @var string|null
+     * @var ?string
      */
     public $localeBuild;
 
-    /** @var string|null Version of the message catalog for the current session's locale */
+    /** @var ?string Version of the message catalog for the current session's locale */
     public $localeVersion;
 
     /** @var string Short form of the product name */
diff --git a/library/Vspheredb/MappedClass/AlarmEvent.php b/library/Vspheredb/MappedClass/AlarmEvent.php
index 3782a739..65857997 100644
--- a/library/Vspheredb/MappedClass/AlarmEvent.php
+++ b/library/Vspheredb/MappedClass/AlarmEvent.php
@@ -4,6 +4,7 @@
 
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Zend_Db_Adapter_Abstract as ZfDbAdapter;
+use Zend_Db_Adapter_Exception;
 
 abstract class AlarmEvent extends KnownEvent
 {
@@ -19,7 +20,8 @@ public function getDbData(VCenter $vCenter)
     /**
      * @param ZfDbAdapter $db
      * @param VCenter $vCenter
-     * @throws \Zend_Db_Adapter_Exception
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
     public function store(ZfDbAdapter $db, VCenter $vCenter)
     {
@@ -27,9 +29,11 @@ public function store(ZfDbAdapter $db, VCenter $vCenter)
 
         // TODO: don't do so if it is old
         if (isset($this->to) && isset($this->entity)) {
-            $db->update('object', [
-                'overall_status' => $this->to
-            ], $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->entity->entity->_)));
+            $db->update(
+                'object',
+                ['overall_status' => $this->to],
+                $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->entity->entity->_))
+            );
         }
     }
 
diff --git a/library/Vspheredb/MappedClass/AlarmInfo.php b/library/Vspheredb/MappedClass/AlarmInfo.php
index da80eb8a..641c3ae6 100644
--- a/library/Vspheredb/MappedClass/AlarmInfo.php
+++ b/library/Vspheredb/MappedClass/AlarmInfo.php
@@ -16,7 +16,7 @@ class AlarmInfo
      */
     public $alarm;
 
-    /** @var int|null The event ID that records the alarm creation */
+    /** @var ?int The event ID that records the alarm creation */
     public $creationEventId;
 
     /**
diff --git a/library/Vspheredb/MappedClass/AlarmSpec.php b/library/Vspheredb/MappedClass/AlarmSpec.php
index 0b69dcd4..debe9102 100644
--- a/library/Vspheredb/MappedClass/AlarmSpec.php
+++ b/library/Vspheredb/MappedClass/AlarmSpec.php
@@ -2,10 +2,12 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * Parameters for alarm creation
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class AlarmSpec
 {
     /** @var AlarmAction Action to perform when the alarm is triggered */
diff --git a/library/Vspheredb/MappedClass/AlarmState.php b/library/Vspheredb/MappedClass/AlarmState.php
index a4a128fc..7967ee76 100644
--- a/library/Vspheredb/MappedClass/AlarmState.php
+++ b/library/Vspheredb/MappedClass/AlarmState.php
@@ -15,7 +15,7 @@ class AlarmState
      * Flag to indicate if the alarm's actions have been acknowledged for the
      * associated ManagedEntity
      *
-     * @var bool|null
+     * @var ?bool
      */
     public $acknowledged;
 
@@ -23,7 +23,7 @@ class AlarmState
      * The user who acknowledged this triggering. If the triggering has not been
      * acknowledged, then the value is not valid
      *
-     * @var string|null
+     * @var ?string
      */
     public $acknowledgedByUser;
 
@@ -56,7 +56,7 @@ class AlarmState
      *
      * Since vSphere API 6.0
      *
-     * @var int|null
+     * @var ?int
      */
     public $eventKey;
 
diff --git a/library/Vspheredb/MappedClass/ApiClassMap.php b/library/Vspheredb/MappedClass/ApiClassMap.php
index a7bb0270..cb1393d3 100644
--- a/library/Vspheredb/MappedClass/ApiClassMap.php
+++ b/library/Vspheredb/MappedClass/ApiClassMap.php
@@ -12,11 +12,7 @@ class ApiClassMap
 
     public static function getMap()
     {
-        if (self::$map === null) {
-            self::$map = static::prepareMap();
-        }
-
-        return self::$map;
+        return self::$map ??= static::prepareMap();
     }
 
     /**
@@ -41,74 +37,71 @@ public static function requireTypeMap(string $type): string
             return $map[$type];
         }
 
-        throw new RuntimeException(sprintf(
-            'Type "%s" has no class mapping',
-            $type
-        ));
+        throw new RuntimeException(sprintf('Type "%s" has no class mapping', $type));
     }
 
     public static function prepareMap()
     {
         // Hint: put more specific classes on top, otherwise a more generic one might match
-        $map = [
+        return [
             'RetrieveResult'             => RetrieveResult::class,
             'RetrievePropertiesResponse' => RetrievePropertiesResponse::class,
-            'DynamicData'          => DynamicData::class,
-            'DynamicProperty'      => DynamicProperty::class,
-            'ObjectContent'        => ObjectContent::class,
-            'KeyValue'             => KeyValue::class,
-            'MissingProperty'      => MissingProperty::class,
-            'InvalidProperty'      => InvalidProperty::class,
-            'SystemError'          => SystemError::class,
-            'NotAuthenticated'     => NotAuthenticated::class,
-            'NoPermission'         => NoPermission::class,
-            'SecurityError'        => SecurityError::class,
-            'LocalizedMethodFault' => LocalizedMethodFault::class,
-            'ServiceContent'       => ServiceContent::class,
-            'AboutInfo'            => AboutInfo::class,
-            'Folder'               => Folder::class,
-            'Datacenter'           => Datacenter::class,
-            'Datastore'            => Datastore::class,
-            'ResourcePool'         => ResourcePool::class,
-            'Network'              => Network::class,
-            'SessionManager'       => SessionManager::class,
-            'UserSession'          => UserSession::class,
-            'Tag'                  => Tag::class,
-            'RetrieveOptions'      => RetrieveOptions::class,
-
-            'ObjectSpec'           => ObjectSpec::class,
-            'SelectionSpec'        => SelectionSpec::class,
-            'TraversalSpec'        => TraversalSpec::class,
-            'PropertyFilterSpec'   => PropertyFilterSpec::class,
-            'PropertySpec'         => PropertySpec::class,
-            'EventFilterSpec'      => EventFilterSpec::class,
+            'DynamicData'                => DynamicData::class,
+            'DynamicProperty'            => DynamicProperty::class,
+            'ObjectContent'              => ObjectContent::class,
+            'KeyValue'                   => KeyValue::class,
+            'MissingProperty'            => MissingProperty::class,
+            'InvalidProperty'            => InvalidProperty::class,
+            'SystemError'                => SystemError::class,
+            'NotAuthenticated'           => NotAuthenticated::class,
+            'NoPermission'               => NoPermission::class,
+            'SecurityError'              => SecurityError::class,
+            'LocalizedMethodFault'       => LocalizedMethodFault::class,
+            'ServiceContent'             => ServiceContent::class,
+            'AboutInfo'                  => AboutInfo::class,
+            'Folder'                     => Folder::class,
+            'Datacenter'                 => Datacenter::class,
+            'Datastore'                  => Datastore::class,
+            'ResourcePool'               => ResourcePool::class,
+            'Network'                    => Network::class,
+            'SessionManager'             => SessionManager::class,
+            'UserSession'                => UserSession::class,
+            'Tag'                        => Tag::class,
+            'RetrieveOptions'            => RetrieveOptions::class,
+
+            'ObjectSpec'                => ObjectSpec::class,
+            'SelectionSpec'             => SelectionSpec::class,
+            'TraversalSpec'             => TraversalSpec::class,
+            'PropertyFilterSpec'        => PropertyFilterSpec::class,
+            'PropertySpec'              => PropertySpec::class,
+            'EventFilterSpec'           => EventFilterSpec::class,
             'EventFilterSpecByEntity'   => EventFilterSpecByEntity::class,
             'EventFilterSpecByTime'     => EventFilterSpecByTime::class,
             'EventFilterSpecByUsername' => EventFilterSpecByUsername::class,
 
-            'ManagedEntity'        => ManagedEntity::class,
-            'AlarmState'           => AlarmState::class,
-            'Action'               => Action::class,
-            'Alarm'                => Alarm::class,
-            'AlarmAction'          => AlarmAction::class,
-            'AlarmExpression'      => AlarmExpression::class,
-            'AlarmInfo'            => AlarmInfo::class,
-            'AlarmSetting'         => AlarmSetting::class,
+            'ManagedEntity'                       => ManagedEntity::class,
+            'AlarmState'                          => AlarmState::class,
+            'Action'                              => Action::class,
+            'Alarm'                               => Alarm::class,
+            'AlarmAction'                         => AlarmAction::class,
+            'AlarmExpression'                     => AlarmExpression::class,
+            'AlarmInfo'                           => AlarmInfo::class,
+            'AlarmSetting'                        => AlarmSetting::class,
             'AlarmTriggeringAction'               => AlarmTriggeringAction::class,
             'AlarmTriggeringActionTransitionSpec' => AlarmTriggeringActionTransitionSpec::class,
-            'AndAlarmExpression'   => AndAlarmExpression::class,
-            'CreateTaskAction'     => CreateTaskAction::class,
-            'EventAlarmExpression' => EventAlarmExpression::class,
-            'EventAlarmExpressionComparison' => EventAlarmExpressionComparison::class,
-            'ExtensibleManagedObject' => ExtensibleManagedObject::class,
-            'MethodAction'            => MethodAction::class,
-            'MethodActionArgument'    => MethodActionArgument::class,
-            'MetricAlarmExpression'   => MetricAlarmExpression::class,
-            'OrAlarmExpression'       => OrAlarmExpression::class,
-            'RunScriptAction'         => RunScriptAction::class,
-            'SendEmailAction'         => SendEmailAction::class,
-            'SendSNMPAction'          => SendSNMPAction::class,
-            'StateAlarmExpression'    => StateAlarmExpression::class,
+            'AndAlarmExpression'                  => AndAlarmExpression::class,
+            'CreateTaskAction'                    => CreateTaskAction::class,
+            'EventAlarmExpression'                => EventAlarmExpression::class,
+            'EventAlarmExpressionComparison'      => EventAlarmExpressionComparison::class,
+            'ExtensibleManagedObject'             => ExtensibleManagedObject::class,
+            'MethodAction'                        => MethodAction::class,
+            'MethodActionArgument'                => MethodActionArgument::class,
+            'MetricAlarmExpression'               => MetricAlarmExpression::class,
+            'OrAlarmExpression'                   => OrAlarmExpression::class,
+            'RunScriptAction'                     => RunScriptAction::class,
+            'SendEmailAction'                     => SendEmailAction::class,
+            'SendSNMPAction'                      => SendSNMPAction::class,
+            'StateAlarmExpression'                => StateAlarmExpression::class,
 
             // 'ManagedObjectNotFoundFault' => "$base\\ManagedObjectNotFoundFault",
             // 'AlarmEvent'              => "$base\\AlarmEvent",
@@ -187,37 +180,37 @@ public static function prepareMap()
             'DatastoreEventArgument'       => DatastoreEventArgument::class,
             'HostEventArgument'            => HostEventArgument::class,
             'VmEventArgument'              => VmEventArgument::class,
-            'ManagedObjectReference' => ManagedObjectReference::class,
-            'NumericRange'           => NumericRange::class,
-            'ClusterDasFdmHostState' => ClusterDasFdmHostState::class,
-            'CustomFieldsManager'    => CustomFieldsManager::class,
-            'CustomFieldDef'         => CustomFieldDef::class,
-            'CustomFieldValue'       => CustomFieldValue::class,
-            'PrivilegePolicyDef'     => PrivilegePolicyDef::class,
-
-            'DistributedVirtualSwitchPortConnection'    => DistributedVirtualSwitchPortConnection::class,
-            'DistributedVirtualSwitchHostMemberBacking' => DistributedVirtualSwitchHostMemberBacking::class,
+            'ManagedObjectReference'       => ManagedObjectReference::class,
+            'NumericRange'                 => NumericRange::class,
+            'ClusterDasFdmHostState'       => ClusterDasFdmHostState::class,
+            'CustomFieldsManager'          => CustomFieldsManager::class,
+            'CustomFieldDef'               => CustomFieldDef::class,
+            'CustomFieldValue'             => CustomFieldValue::class,
+            'PrivilegePolicyDef'           => PrivilegePolicyDef::class,
+
+            'DistributedVirtualSwitchPortConnection'        => DistributedVirtualSwitchPortConnection::class,
+            'DistributedVirtualSwitchHostMemberBacking'     => DistributedVirtualSwitchHostMemberBacking::class,
             'DistributedVirtualSwitchHostMemberPnicBacking' => DistributedVirtualSwitchHostMemberPnicBacking::class,
-            'DistributedVirtualSwitchHostMemberPnicSpec' => DistributedVirtualSwitchHostMemberPnicSpec::class,
-            'HostDnsConfig'           => HostDnsConfig::class,
-            'HostIpConfig'            => HostIpConfig::class,
-            'HostIpConfigIpV6Address' => HostIpConfigIpV6Address::class,
-            'HostIpConfigIpV6AddressConfiguration' => HostIpConfigIpV6AddressConfiguration::class,
-            'HostIpRouteConfig'       => HostIpRouteConfig::class,
-            'HostNetStackInstance'    => HostNetStackInstance::class,
-            'HostNetworkInfo'         => HostNetworkInfo::class,
-            'HostOpaqueNetworkInfo'   => HostOpaqueNetworkInfo::class,
-            'HostOpaqueSwitch'        => HostOpaqueSwitch::class,
-            'HostPortGroup'           => HostPortGroup::class,
-            'HostPortGroupPort'       => HostPortGroupPort::class,
-            'HostPortGroupSpec'       => HostPortGroupSpec::class,
-            'HostProxySwitch'         => HostProxySwitch::class,
-            'HostProxySwitchSpec'     => HostProxySwitchSpec::class,
-            'HostVirtualNic'          => HostVirtualNic::class,
-            'HostVirtualNicSpec'      => HostVirtualNicSpec::class,
-            'HostVirtualSwitch'       => HostVirtualSwitch::class,
-            'HostVirtualSwitchBridge' => HostVirtualSwitchBridge::class,
-            'HostVirtualSwitchSpec'   => HostVirtualSwitchSpec::class,
+            'DistributedVirtualSwitchHostMemberPnicSpec'    => DistributedVirtualSwitchHostMemberPnicSpec::class,
+            'HostDnsConfig'                                 => HostDnsConfig::class,
+            'HostIpConfig'                                  => HostIpConfig::class,
+            'HostIpConfigIpV6Address'                       => HostIpConfigIpV6Address::class,
+            'HostIpConfigIpV6AddressConfiguration'          => HostIpConfigIpV6AddressConfiguration::class,
+            'HostIpRouteConfig'                             => HostIpRouteConfig::class,
+            'HostNetStackInstance'                          => HostNetStackInstance::class,
+            'HostNetworkInfo'                               => HostNetworkInfo::class,
+            'HostOpaqueNetworkInfo'                         => HostOpaqueNetworkInfo::class,
+            'HostOpaqueSwitch'                              => HostOpaqueSwitch::class,
+            'HostPortGroup'                                 => HostPortGroup::class,
+            'HostPortGroupPort'                             => HostPortGroupPort::class,
+            'HostPortGroupSpec'                             => HostPortGroupSpec::class,
+            'HostProxySwitch'                               => HostProxySwitch::class,
+            'HostProxySwitchSpec'                           => HostProxySwitchSpec::class,
+            'HostVirtualNic'                                => HostVirtualNic::class,
+            'HostVirtualNicSpec'                            => HostVirtualNicSpec::class,
+            'HostVirtualSwitch'                             => HostVirtualSwitch::class,
+            'HostVirtualSwitchBridge'                       => HostVirtualSwitchBridge::class,
+            'HostVirtualSwitchSpec'                         => HostVirtualSwitchSpec::class,
 
             'PhysicalNic'             => PhysicalNic::class,
             'PhysicalNicLinkInfo'     => PhysicalNicLinkInfo::class,
@@ -237,9 +230,7 @@ public static function prepareMap()
             'HostTcpHba'                              => HostTcpHba::class,
 
             'GuestNicInfo'                            => GuestNicInfo::class,
-            'NetDnsConfigInfo'                        => NetDnsConfigInfo::class,
+            'NetDnsConfigInfo'                        => NetDnsConfigInfo::class
         ];
-
-        return $map;
     }
 }
diff --git a/library/Vspheredb/MappedClass/ClusterDasFdmHostState.php b/library/Vspheredb/MappedClass/ClusterDasFdmHostState.php
index a8d59975..9fee295a 100644
--- a/library/Vspheredb/MappedClass/ClusterDasFdmHostState.php
+++ b/library/Vspheredb/MappedClass/ClusterDasFdmHostState.php
@@ -2,8 +2,10 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
 use gipfl\Json\JsonSerialization;
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
+use ReturnTypeWillChange;
 
 /**
  * https://www.vmware.com/support/developer/converter-sdk/conv61_apireference/vim.cluster.DasFdmHostState.html
@@ -38,7 +40,7 @@
  * restarting VMs as required. All FDMs provide the VM/Application Health
  * Monitoring Service.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class ClusterDasFdmHostState implements JsonSerialization
 {
     /**
@@ -96,7 +98,7 @@ class ClusterDasFdmHostState implements JsonSerialization
      */
     public $state;
 
-    /** @var ManagedObjectReference|null */
+    /** @var ?ManagedObjectReference */
     public $stateReporter;
 
     public static function fromSerialization($any)
@@ -108,12 +110,12 @@ public static function fromSerialization($any)
         return $self;
     }
 
-    #[\ReturnTypeWillChange]
+    #[ReturnTypeWillChange]
     public function jsonSerialize()
     {
         return (object) [
             'state' => $this->state,
-            'stateReporter' => $this->stateReporter,
+            'stateReporter' => $this->stateReporter
         ];
     }
 }
diff --git a/library/Vspheredb/MappedClass/CustomFieldValue.php b/library/Vspheredb/MappedClass/CustomFieldValue.php
index a7fe837f..44ffdc46 100644
--- a/library/Vspheredb/MappedClass/CustomFieldValue.php
+++ b/library/Vspheredb/MappedClass/CustomFieldValue.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class CustomFieldValue
 {
     /** @var int CustomField ID - references CustomFieldDefs in CustomFieldsManager */
diff --git a/library/Vspheredb/MappedClass/CustomFieldsManager.php b/library/Vspheredb/MappedClass/CustomFieldsManager.php
index 4c92ce86..782d36ec 100644
--- a/library/Vspheredb/MappedClass/CustomFieldsManager.php
+++ b/library/Vspheredb/MappedClass/CustomFieldsManager.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class CustomFieldsManager
 {
     /** @var CustomFieldDef[] */
diff --git a/library/Vspheredb/MappedClass/DatacenterConfigInfo.php b/library/Vspheredb/MappedClass/DatacenterConfigInfo.php
index e801d04a..eb1d5bf2 100644
--- a/library/Vspheredb/MappedClass/DatacenterConfigInfo.php
+++ b/library/Vspheredb/MappedClass/DatacenterConfigInfo.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class DatacenterConfigInfo
 {
     /**
diff --git a/library/Vspheredb/MappedClass/DistributedVirtualSwitchHostMemberPnicSpec.php b/library/Vspheredb/MappedClass/DistributedVirtualSwitchHostMemberPnicSpec.php
index 5908a6de..1d8c4e53 100644
--- a/library/Vspheredb/MappedClass/DistributedVirtualSwitchHostMemberPnicSpec.php
+++ b/library/Vspheredb/MappedClass/DistributedVirtualSwitchHostMemberPnicSpec.php
@@ -2,10 +2,12 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * Specification for an individual physical NIC
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class DistributedVirtualSwitchHostMemberPnicSpec
 {
     /**
diff --git a/library/Vspheredb/MappedClass/DistributedVirtualSwitchPortConnection.php b/library/Vspheredb/MappedClass/DistributedVirtualSwitchPortConnection.php
index b9aad901..cf2b1be8 100644
--- a/library/Vspheredb/MappedClass/DistributedVirtualSwitchPortConnection.php
+++ b/library/Vspheredb/MappedClass/DistributedVirtualSwitchPortConnection.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * The DistributedVirtualSwitchPortConnection data object represents a connection
  * or association between a DistributedVirtualPortgroup or a DistributedVirtualPort
@@ -11,7 +13,7 @@
  * - Host virtual NIC (HostVirtualNic)
  * - Physical NIC (HostNetworkInfo.pnic)
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class DistributedVirtualSwitchPortConnection
 {
     /**
diff --git a/library/Vspheredb/MappedClass/DynamicData.php b/library/Vspheredb/MappedClass/DynamicData.php
index 503142f1..08c88ac9 100644
--- a/library/Vspheredb/MappedClass/DynamicData.php
+++ b/library/Vspheredb/MappedClass/DynamicData.php
@@ -2,12 +2,14 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class DynamicData
 {
-    /** @var DynamicProperty[]|null */
+    /** @var ?DynamicProperty[] */
     public $dynamicProperty;
 
-    /** @var string|null */
+    /** @var ?string */
     public $dynamicType;
 }
diff --git a/library/Vspheredb/MappedClass/DynamicProperty.php b/library/Vspheredb/MappedClass/DynamicProperty.php
index da3daca9..449e6d25 100644
--- a/library/Vspheredb/MappedClass/DynamicProperty.php
+++ b/library/Vspheredb/MappedClass/DynamicProperty.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class DynamicProperty
 {
     /** @var string */
diff --git a/library/Vspheredb/MappedClass/ElementDescription.php b/library/Vspheredb/MappedClass/ElementDescription.php
index 528f1493..3d0902f6 100644
--- a/library/Vspheredb/MappedClass/ElementDescription.php
+++ b/library/Vspheredb/MappedClass/ElementDescription.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class ElementDescription
 {
     /** @var string */
diff --git a/library/Vspheredb/MappedClass/EntityEventArgument.php b/library/Vspheredb/MappedClass/EntityEventArgument.php
index dcb478a8..8e69017e 100644
--- a/library/Vspheredb/MappedClass/EntityEventArgument.php
+++ b/library/Vspheredb/MappedClass/EntityEventArgument.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 abstract class EntityEventArgument
 {
     /** @var string */
diff --git a/library/Vspheredb/MappedClass/EventAlarmExpression.php b/library/Vspheredb/MappedClass/EventAlarmExpression.php
index f724be4a..661ea7d1 100644
--- a/library/Vspheredb/MappedClass/EventAlarmExpression.php
+++ b/library/Vspheredb/MappedClass/EventAlarmExpression.php
@@ -32,7 +32,7 @@ class EventAlarmExpression extends AlarmExpression
      *
      * Either eventType or eventTypeId must be set.
      *
-     * @var string|null
+     * @var ?string
      */
     public $eventTypeId;
 
diff --git a/library/Vspheredb/MappedClass/EventFilterSpecByTime.php b/library/Vspheredb/MappedClass/EventFilterSpecByTime.php
index 23659f84..90742b4d 100644
--- a/library/Vspheredb/MappedClass/EventFilterSpecByTime.php
+++ b/library/Vspheredb/MappedClass/EventFilterSpecByTime.php
@@ -2,10 +2,12 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * This option specifies a time range used to filter event history
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class EventFilterSpecByTime
 {
     /**
@@ -27,24 +29,17 @@ class EventFilterSpecByTime
     /**
      * @param ?int|string $beginTime
      * @param ?int|string $endTime
+     *
      * @return static
      */
     public static function create($beginTime = null, $endTime = null)
     {
         $self = new static();
         if ($beginTime) {
-            if (is_int($beginTime)) {
-                $self->beginTime = self::makeDateTime($beginTime);
-            } else {
-                $self->beginTime = $beginTime;
-            }
+            $self->beginTime = is_int($beginTime) ? self::makeDateTime($beginTime) : $beginTime;
         }
         if ($endTime) {
-            if (is_int($endTime)) {
-                $self->endTime = self::makeDateTime($endTime);
-            } else {
-                $self->endTime = $endTime;
-            }
+            $self->endTime = is_int($endTime) ? self::makeDateTime($endTime) : $endTime;
         }
 
         return $self;
@@ -52,7 +47,9 @@ public static function create($beginTime = null, $endTime = null)
 
     /**
      * DateTime for SOAP call
+     *
      * @param $timestamp
+     *
      * @return string
      */
     protected static function makeDateTime($timestamp)
diff --git a/library/Vspheredb/MappedClass/EventHistoryCollector.php b/library/Vspheredb/MappedClass/EventHistoryCollector.php
index 75aec7a2..70118191 100644
--- a/library/Vspheredb/MappedClass/EventHistoryCollector.php
+++ b/library/Vspheredb/MappedClass/EventHistoryCollector.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class EventHistoryCollector
 {
     /**
diff --git a/library/Vspheredb/MappedClass/Fault.php b/library/Vspheredb/MappedClass/Fault.php
index c1b36831..df4e8018 100644
--- a/library/Vspheredb/MappedClass/Fault.php
+++ b/library/Vspheredb/MappedClass/Fault.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 abstract class Fault
 {
     abstract public function getMessage();
diff --git a/library/Vspheredb/MappedClass/GlobalMessageChangedEvent.php b/library/Vspheredb/MappedClass/GlobalMessageChangedEvent.php
index 05fd094c..822b6a13 100644
--- a/library/Vspheredb/MappedClass/GlobalMessageChangedEvent.php
+++ b/library/Vspheredb/MappedClass/GlobalMessageChangedEvent.php
@@ -7,6 +7,6 @@ class GlobalMessageChangedEvent extends SessionEvent
     /** @var string The new message that was set */
     public $message;
 
-    /** @var string|null The previous message that was set */
+    /** @var ?string The previous message that was set */
     public $prevMessage;
 }
diff --git a/library/Vspheredb/MappedClass/HostDnsConfig.php b/library/Vspheredb/MappedClass/HostDnsConfig.php
index 3d8e0bfc..5193dd2c 100644
--- a/library/Vspheredb/MappedClass/HostDnsConfig.php
+++ b/library/Vspheredb/MappedClass/HostDnsConfig.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * This data object type describes the DNS configuration
  *
@@ -13,7 +15,7 @@
  * The address can also consist of the symbol '::' to represent multiple 16-bit
  * groups of contiguous 0's only once in an address as described in RFC 2373.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostDnsConfig
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostIpConfig.php b/library/Vspheredb/MappedClass/HostIpConfig.php
index 5b6f12d7..7c7dafc6 100644
--- a/library/Vspheredb/MappedClass/HostIpConfig.php
+++ b/library/Vspheredb/MappedClass/HostIpConfig.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class HostIpConfig
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostIpConfigIpV6Address.php b/library/Vspheredb/MappedClass/HostIpConfigIpV6Address.php
index 61623842..a086a755 100644
--- a/library/Vspheredb/MappedClass/HostIpConfigIpV6Address.php
+++ b/library/Vspheredb/MappedClass/HostIpConfigIpV6Address.php
@@ -31,7 +31,7 @@ class HostIpConfigIpV6Address
      * The ipv6 address. When DHCP is enabled, this property reflects the
      * current IP configuration and cannot be set
      *
-     * @var string|null
+     * @var ?string
      */
     public $ipAddress;
 
diff --git a/library/Vspheredb/MappedClass/HostIpConfigIpV6AddressConfiguration.php b/library/Vspheredb/MappedClass/HostIpConfigIpV6AddressConfiguration.php
index 14f5652a..7dcf37cc 100644
--- a/library/Vspheredb/MappedClass/HostIpConfigIpV6AddressConfiguration.php
+++ b/library/Vspheredb/MappedClass/HostIpConfigIpV6AddressConfiguration.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class HostIpConfigIpV6AddressConfiguration
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostIpRouteConfig.php b/library/Vspheredb/MappedClass/HostIpRouteConfig.php
index 574745e6..bff36d42 100644
--- a/library/Vspheredb/MappedClass/HostIpRouteConfig.php
+++ b/library/Vspheredb/MappedClass/HostIpRouteConfig.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * IP Route Configuration. All IPv4 addresses, subnet addresses, and netmasks
  * are specified as strings using dotted decimal notation. For example, "192.0.2.1".
@@ -11,7 +13,7 @@
  * to represent multiple 16-bit groups of contiguous 0's only once in an address
  * as described in RFC 2373.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostIpRouteConfig
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostMultipathInfo.php b/library/Vspheredb/MappedClass/HostMultipathInfo.php
index 67b84940..64497379 100644
--- a/library/Vspheredb/MappedClass/HostMultipathInfo.php
+++ b/library/Vspheredb/MappedClass/HostMultipathInfo.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * The HostMultipathInfo data object describes the multipathing policy configuration to determine the storage failover
  * policies for a SCSI logical unit. The multipathing policy configuration operates on SCSI logical units and the paths
@@ -15,7 +17,7 @@
  * object, only native multipathing exists. That means for these hosts, the MultipathInfo object contains the complete
  * set of LUNs and paths on the LUNs available on the host.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostMultipathInfo extends DynamicData
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostNetStackInstance.php b/library/Vspheredb/MappedClass/HostNetStackInstance.php
index e171bdee..94ddc29d 100644
--- a/library/Vspheredb/MappedClass/HostNetStackInstance.php
+++ b/library/Vspheredb/MappedClass/HostNetStackInstance.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class HostNetStackInstance
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostNetworkInfo.php b/library/Vspheredb/MappedClass/HostNetworkInfo.php
index fbf10e57..40119927 100644
--- a/library/Vspheredb/MappedClass/HostNetworkInfo.php
+++ b/library/Vspheredb/MappedClass/HostNetworkInfo.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class HostNetworkInfo
 {
     /** @var boolean */
diff --git a/library/Vspheredb/MappedClass/HostNumericSensorInfo.php b/library/Vspheredb/MappedClass/HostNumericSensorInfo.php
index f26eeadd..43ae086a 100644
--- a/library/Vspheredb/MappedClass/HostNumericSensorInfo.php
+++ b/library/Vspheredb/MappedClass/HostNumericSensorInfo.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class HostNumericSensorInfo
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostOpaqueNetworkInfo.php b/library/Vspheredb/MappedClass/HostOpaqueNetworkInfo.php
index 223eb9b1..c2e62a47 100644
--- a/library/Vspheredb/MappedClass/HostOpaqueNetworkInfo.php
+++ b/library/Vspheredb/MappedClass/HostOpaqueNetworkInfo.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class HostOpaqueNetworkInfo
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostOpaqueSwitch.php b/library/Vspheredb/MappedClass/HostOpaqueSwitch.php
index b0d09f99..05e8fd72 100644
--- a/library/Vspheredb/MappedClass/HostOpaqueSwitch.php
+++ b/library/Vspheredb/MappedClass/HostOpaqueSwitch.php
@@ -2,11 +2,13 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * The OpaqueSwitch contains basic information about virtual switches that are
  * managed by a management plane outside of vSphere.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostOpaqueSwitch
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostPortGroup.php b/library/Vspheredb/MappedClass/HostPortGroup.php
index df7d86d0..c6b582a8 100644
--- a/library/Vspheredb/MappedClass/HostPortGroup.php
+++ b/library/Vspheredb/MappedClass/HostPortGroup.php
@@ -2,12 +2,14 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * This data object type is used to describe port groups. Port groups are used
  * to group virtual network adapters on a virtual switch, associating them with
  * networks and network policies
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostPortGroup
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostPortGroupPort.php b/library/Vspheredb/MappedClass/HostPortGroupPort.php
index a1cd099a..88c717af 100644
--- a/library/Vspheredb/MappedClass/HostPortGroupPort.php
+++ b/library/Vspheredb/MappedClass/HostPortGroupPort.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * A Port data object type is a runtime representation of network connectivity
  * between a network service or virtual machine and a virtual switch. This is
@@ -9,7 +11,7 @@
  * configuration aspects of the network connection. The Port object provides
  * runtime statistics.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostPortGroupPort
 {
     /**
@@ -37,7 +39,7 @@ class HostPortGroupPort
      * - unknown          : This port group serves an entity of unspecified kind
      * - virtualMachine   : A virtual machine is connected to this port group
      *
-     * @var string|null
+     * @var ?string
      */
     public $type;
 }
diff --git a/library/Vspheredb/MappedClass/HostPortGroupSpec.php b/library/Vspheredb/MappedClass/HostPortGroupSpec.php
index f9a0fcee..c0714b0a 100644
--- a/library/Vspheredb/MappedClass/HostPortGroupSpec.php
+++ b/library/Vspheredb/MappedClass/HostPortGroupSpec.php
@@ -2,11 +2,13 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * This data object type describes the PortGroup specification representing the
  * properties on a PortGroup that can be configured
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostPortGroupSpec
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostProxySwitch.php b/library/Vspheredb/MappedClass/HostProxySwitch.php
index 38775e2a..22ebb6cd 100644
--- a/library/Vspheredb/MappedClass/HostProxySwitch.php
+++ b/library/Vspheredb/MappedClass/HostProxySwitch.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * The HostProxySwitch is a software entity which represents the component of a
  * DistributedVirtualSwitch on a particular host.
@@ -10,7 +12,7 @@
  * a vSphere distributed switch. The host proxy switch replicates the networking
  * configuration set on the vSphere distributed switch to the particular host.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostProxySwitch
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostProxySwitchSpec.php b/library/Vspheredb/MappedClass/HostProxySwitchSpec.php
index 80f66e69..a6069fc1 100644
--- a/library/Vspheredb/MappedClass/HostProxySwitchSpec.php
+++ b/library/Vspheredb/MappedClass/HostProxySwitchSpec.php
@@ -2,11 +2,13 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * This data object type describes the HostProxySwitch specification representing
  * the properties on a HostProxySwitch that can be configured once the object exists
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostProxySwitchSpec
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostVirtualNic.php b/library/Vspheredb/MappedClass/HostVirtualNic.php
index 43e13be6..1255531e 100644
--- a/library/Vspheredb/MappedClass/HostVirtualNic.php
+++ b/library/Vspheredb/MappedClass/HostVirtualNic.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class HostVirtualNic
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostVirtualNicSpec.php b/library/Vspheredb/MappedClass/HostVirtualNicSpec.php
index 1d2e59a7..a2d648f7 100644
--- a/library/Vspheredb/MappedClass/HostVirtualNicSpec.php
+++ b/library/Vspheredb/MappedClass/HostVirtualNicSpec.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class HostVirtualNicSpec
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostVirtualSwitch.php b/library/Vspheredb/MappedClass/HostVirtualSwitch.php
index 5f11543c..de6a1255 100644
--- a/library/Vspheredb/MappedClass/HostVirtualSwitch.php
+++ b/library/Vspheredb/MappedClass/HostVirtualSwitch.php
@@ -2,12 +2,14 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * The virtual switch is a software entity to which multiple virtual network
  * adapters can connect to create a virtual network. It can also be bridged to
  * a physical network
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostVirtualSwitch
 {
     /**
diff --git a/library/Vspheredb/MappedClass/HostVirtualSwitchBridge.php b/library/Vspheredb/MappedClass/HostVirtualSwitchBridge.php
index 616cb8e2..b9657e52 100644
--- a/library/Vspheredb/MappedClass/HostVirtualSwitchBridge.php
+++ b/library/Vspheredb/MappedClass/HostVirtualSwitchBridge.php
@@ -2,11 +2,13 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * A bridge connects a virtual switch to a physical network adapter. There are
  * multiple types of bridges.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostVirtualSwitchBridge extends DynamicData
 {
 }
diff --git a/library/Vspheredb/MappedClass/HostVirtualSwitchSpec.php b/library/Vspheredb/MappedClass/HostVirtualSwitchSpec.php
index 7b616067..90f13f8f 100644
--- a/library/Vspheredb/MappedClass/HostVirtualSwitchSpec.php
+++ b/library/Vspheredb/MappedClass/HostVirtualSwitchSpec.php
@@ -2,11 +2,13 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * This data object type describes the VirtualSwitch specification representing
  * the properties on a VirtualSwitch that can be configured once the object exists
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class HostVirtualSwitchSpec
 {
     /**
diff --git a/library/Vspheredb/MappedClass/KeyValue.php b/library/Vspheredb/MappedClass/KeyValue.php
index 6ed821f7..77684bfd 100644
--- a/library/Vspheredb/MappedClass/KeyValue.php
+++ b/library/Vspheredb/MappedClass/KeyValue.php
@@ -2,10 +2,12 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * Non-localized key/value pair
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class KeyValue
 {
     /**
diff --git a/library/Vspheredb/MappedClass/KnownEvent.php b/library/Vspheredb/MappedClass/KnownEvent.php
index fbb3bd16..699523ec 100644
--- a/library/Vspheredb/MappedClass/KnownEvent.php
+++ b/library/Vspheredb/MappedClass/KnownEvent.php
@@ -2,10 +2,13 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
 use DateTime;
 use gipfl\Json\JsonSerialization;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
+use ReturnTypeWillChange;
 use Zend_Db_Adapter_Abstract as ZfDbAdapter;
+use Zend_Db_Adapter_Exception;
 
 /**
  * KnownEvent
@@ -13,7 +16,7 @@
  * We use this as a base class for all vim.event.Event implementations
  * handled by us
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 abstract class KnownEvent implements JsonSerialization
 {
     /** @var int The parent or group ID */
@@ -28,22 +31,22 @@ abstract class KnownEvent implements JsonSerialization
     /** @var string The user who caused the event */
     public $userName;
 
-    /** @var string|null A formatted text message describing the event. The message may be localized.*/
+    /** @var ?string A formatted text message describing the event. The message may be localized.*/
     public $fullFormattedMessage;
 
-    /** @var ComputeResourceEventArgument|null */
+    /** @var ?ComputeResourceEventArgument */
     public $computeResource;
 
-    /** @var DatacenterEventArgument|null */
+    /** @var ?DatacenterEventArgument */
     public $datacenter;
 
     /** @var DatastoreEventArgument */
     public $ds;
 
-    /** @var HostEventArgument|null */
+    /** @var ?HostEventArgument */
     public $host;
 
-    /** @var VmEventArgument|null */
+    /** @var ?VmEventArgument */
     public $vm;
 
     protected $table;
@@ -58,7 +61,7 @@ public function getDbData(VCenter $vCenter)
             'ts_event_ms'    => $this->getTimestampMs(),
             'event_type'     => array_pop($classParts),
             'event_key'      => $this->key,
-            'event_chain_id' => $this->chainId,
+            'event_chain_id' => $this->chainId
         ];
         if (isset($this->fullFormattedMessage) && strlen($this->fullFormattedMessage)) {
             $data['full_message'] = $this->fullFormattedMessage;
@@ -69,17 +72,14 @@ public function getDbData(VCenter $vCenter)
 
     public function getTimestampMs()
     {
-        if ($this->timestampMs === null) {
-            $this->timestampMs = $this->timeStringToUnixMs($this->createdTime);
-        }
-
-        return $this->timestampMs;
+        return $this->timestampMs ??= $this->timeStringToUnixMs($this->createdTime);
     }
 
     /**
      * @param ZfDbAdapter $db
      * @param VCenter $vCenter
-     * @throws \Zend_Db_Adapter_Exception
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
     public function store(ZfDbAdapter $db, VCenter $vCenter)
     {
@@ -106,7 +106,7 @@ public static function fromSerialization($any)
         return $self;
     }
 
-    #[\ReturnTypeWillChange]
+    #[ReturnTypeWillChange]
     public function jsonSerialize()
     {
         // TODO: serialize without (un)serialize(), as this needs to work across nodes
diff --git a/library/Vspheredb/MappedClass/LocalizedMethodFault.php b/library/Vspheredb/MappedClass/LocalizedMethodFault.php
index 9f122508..7d8f5aa5 100644
--- a/library/Vspheredb/MappedClass/LocalizedMethodFault.php
+++ b/library/Vspheredb/MappedClass/LocalizedMethodFault.php
@@ -2,12 +2,14 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class LocalizedMethodFault
 {
     /** @var MethodFault */
     public $fault;
 
-    /** @var string|null Servers are required to send the localized message, clients are not */
+    /** @var ?string Servers are required to send the localized message, clients are not */
     public $localizedMessage;
 }
diff --git a/library/Vspheredb/MappedClass/ManagedEntity.php b/library/Vspheredb/MappedClass/ManagedEntity.php
index 8f815de8..c70c821f 100644
--- a/library/Vspheredb/MappedClass/ManagedEntity.php
+++ b/library/Vspheredb/MappedClass/ManagedEntity.php
@@ -2,9 +2,10 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
 
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class ManagedEntity
 {
     /**
diff --git a/library/Vspheredb/MappedClass/ManagedObjectNotFoundFault.php b/library/Vspheredb/MappedClass/ManagedObjectNotFoundFault.php
index 6ad11001..d5ac470f 100644
--- a/library/Vspheredb/MappedClass/ManagedObjectNotFoundFault.php
+++ b/library/Vspheredb/MappedClass/ManagedObjectNotFoundFault.php
@@ -2,10 +2,12 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * Unused?
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class ManagedObjectNotFoundFault
 {
 }
diff --git a/library/Vspheredb/MappedClass/MetricAlarmExpression.php b/library/Vspheredb/MappedClass/MetricAlarmExpression.php
index 043668e4..63b278a1 100644
--- a/library/Vspheredb/MappedClass/MetricAlarmExpression.php
+++ b/library/Vspheredb/MappedClass/MetricAlarmExpression.php
@@ -49,7 +49,7 @@ class MetricAlarmExpression extends AlarmExpression
      * the red status is triggered. If unset, the red status is triggered
      * immediately when the red condition becomes true.
      *
-     * @var int|null
+     * @var ?int
      */
     public $redInterval;
 
@@ -70,7 +70,7 @@ class MetricAlarmExpression extends AlarmExpression
      * before the yellow status is triggered. If unset, the yellow status is
      * triggered immediately when the yellow condition becomes true.
      *
-     * @var int|null
+     * @var ?int
      */
     public $yellowInterval;
 }
diff --git a/library/Vspheredb/MappedClass/MissingProperty.php b/library/Vspheredb/MappedClass/MissingProperty.php
index 61a9b068..3148df10 100644
--- a/library/Vspheredb/MappedClass/MissingProperty.php
+++ b/library/Vspheredb/MappedClass/MissingProperty.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class MissingProperty
 {
     /** @var SytemError|SecurityError These are the known allowed LocalizedMethodFault types */
diff --git a/library/Vspheredb/MappedClass/ObjectContent.php b/library/Vspheredb/MappedClass/ObjectContent.php
index d2ff95e9..1d73710e 100644
--- a/library/Vspheredb/MappedClass/ObjectContent.php
+++ b/library/Vspheredb/MappedClass/ObjectContent.php
@@ -3,6 +3,7 @@
 namespace Icinga\Module\Vspheredb\MappedClass;
 
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
+use ReturnTypeWillChange;
 
 // https://www.vmware.com/support/developer/converter-sdk/conv61_apireference/vmodl.query.PropertyCollector.ObjectContent.html
 
@@ -17,7 +18,7 @@ class ObjectContent
     /**
      * Properties for which values could not be retrieved and the associated fault
      *
-     * @var MissingProperty[]|null
+     * @var ?MissingProperty[]
      */
     public $missingSet;
 
@@ -31,7 +32,7 @@ class ObjectContent
     /**
      * Set of name-value pairs for the properties of the managed object
      *
-     * @var DynamicProperty[]|null
+     * @var ?DynamicProperty[]
      */
     public $propSet;
 
@@ -93,7 +94,7 @@ public function toNewObject()
         return $obj;
     }
 
-    #[\ReturnTypeWillChange]
+    #[ReturnTypeWillChange]
     public function jsonSerialize()
     {
         $obj = [
diff --git a/library/Vspheredb/MappedClass/ObjectSpec.php b/library/Vspheredb/MappedClass/ObjectSpec.php
index 05b0856a..63b29c13 100644
--- a/library/Vspheredb/MappedClass/ObjectSpec.php
+++ b/library/Vspheredb/MappedClass/ObjectSpec.php
@@ -49,6 +49,7 @@ class ObjectSpec
      * @param ManagedObjectReference $obj
      * @param ?SelectionSpec[] $selectSet
      * @param ?boolean $skip
+     *
      * @return static
      */
     public static function create(ManagedObjectReference $obj, ?array $selectSet = null, $skip = null)
diff --git a/library/Vspheredb/MappedClass/PerfCounterInfo.php b/library/Vspheredb/MappedClass/PerfCounterInfo.php
index 81278dfd..21f22820 100644
--- a/library/Vspheredb/MappedClass/PerfCounterInfo.php
+++ b/library/Vspheredb/MappedClass/PerfCounterInfo.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class PerfCounterInfo
 {
     /** @var int[] */
diff --git a/library/Vspheredb/MappedClass/PerfEntityMetricCSV.php b/library/Vspheredb/MappedClass/PerfEntityMetricCSV.php
index 48710241..36550d3b 100644
--- a/library/Vspheredb/MappedClass/PerfEntityMetricCSV.php
+++ b/library/Vspheredb/MappedClass/PerfEntityMetricCSV.php
@@ -2,10 +2,12 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
 use gipfl\Json\JsonSerialization;
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
+use ReturnTypeWillChange;
 
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class PerfEntityMetricCSV implements JsonSerialization
 {
     /** @var ManagedObjectReference */
@@ -29,13 +31,13 @@ public static function fromSerialization($any)
         return $self;
     }
 
-    #[\ReturnTypeWillChange]
+    #[ReturnTypeWillChange]
     public function jsonSerialize()
     {
         return (object) [
             'entity'        => $this->entity,
             'sampleInfoCSV' => $this->sampleInfoCSV,
-            'value'         => $this->value,
+            'value'         => $this->value
         ];
     }
 }
diff --git a/library/Vspheredb/MappedClass/PerfInterval.php b/library/Vspheredb/MappedClass/PerfInterval.php
index fad99200..6cee45aa 100644
--- a/library/Vspheredb/MappedClass/PerfInterval.php
+++ b/library/Vspheredb/MappedClass/PerfInterval.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class PerfInterval
 {
     /** @var bool */
diff --git a/library/Vspheredb/MappedClass/PerfMetricId.php b/library/Vspheredb/MappedClass/PerfMetricId.php
index 8bdbe345..434b51ac 100644
--- a/library/Vspheredb/MappedClass/PerfMetricId.php
+++ b/library/Vspheredb/MappedClass/PerfMetricId.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class PerfMetricId
 {
     /** @var int */
@@ -30,7 +32,7 @@ class PerfMetricId
      *   - DELTAFILE, for virtual machine snapshot overhead files
      *   - OTHERFILE, for all other files of a virtual machine
      *
-     * @var string|null
+     * @var ?string
      */
     public $instance;
 
diff --git a/library/Vspheredb/MappedClass/PerfMetricSeriesCSV.php b/library/Vspheredb/MappedClass/PerfMetricSeriesCSV.php
index 458cf543..9e1e0407 100644
--- a/library/Vspheredb/MappedClass/PerfMetricSeriesCSV.php
+++ b/library/Vspheredb/MappedClass/PerfMetricSeriesCSV.php
@@ -2,13 +2,15 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
 use gipfl\Json\JsonSerialization;
+use ReturnTypeWillChange;
 
 /**
  *
  * https://pubs.vmware.com/vsphere-6-5/topic/com.vmware.wssdk.apiref.doc/vim.PerformanceManager.MetricSeriesCSV.html
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class PerfMetricSeriesCSV implements JsonSerialization
 {
     /** @var PerfMetricId */
@@ -26,12 +28,12 @@ public static function fromSerialization($any)
         return $self;
     }
 
-    #[\ReturnTypeWillChange]
+    #[ReturnTypeWillChange]
     public function jsonSerialize()
     {
         return (object) [
             'id'    => $this->id,
-            'value' => $this->value,
+            'value' => $this->value
         ];
     }
 }
diff --git a/library/Vspheredb/MappedClass/PerfQuerySpec.php b/library/Vspheredb/MappedClass/PerfQuerySpec.php
index c3fa7e88..0b841aac 100644
--- a/library/Vspheredb/MappedClass/PerfQuerySpec.php
+++ b/library/Vspheredb/MappedClass/PerfQuerySpec.php
@@ -2,9 +2,10 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
 use Icinga\Module\Vspheredb\DbObject\ManagedObject;
 
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class PerfQuerySpec
 {
     /** @var ManagedObject */
@@ -15,7 +16,7 @@ class PerfQuerySpec
      * to the first available counter. When a startTime is specified, the returned
      * samples do not include the sample at startTime.
      *
-     * @var string|null xsd:dateTime
+     * @var ?string xsd:dateTime
      */
     public $startTime;
 
@@ -25,7 +26,7 @@ class PerfQuerySpec
      * metric value. When an endTime is specified, the returned samples include
      * the sample at endTime.
      *
-     * @var string|null xsd:dateTime
+     * @var ?string xsd:dateTime
      */
     public $endTime;
 
@@ -37,7 +38,7 @@ class PerfQuerySpec
      * To obtain the greatest detail, use the provider’s refreshRate for this
      * property.
      *
-     * @var int|null
+     * @var ?int
      */
     public $intervalId;
 
@@ -50,13 +51,13 @@ class PerfQuerySpec
      * This property is ignored for historical statistics, and is not valid for
      * the QueryPerfComposite operation.
      *
-     * @var int|null
+     * @var ?int
      */
     public $maxSample;
 
-    /** @var string|null enum PerfFormat, 'normal' or 'csv' */
+    /** @var ?string enum PerfFormat, 'normal' or 'csv' */
     public $format;
 
-    /** @var PerfMetricId[]|null */
+    /** @var ?PerfMetricId[] */
     public $metricId;
 }
diff --git a/library/Vspheredb/MappedClass/PerformanceDescription.php b/library/Vspheredb/MappedClass/PerformanceDescription.php
index a24d91c9..50ebb2f5 100644
--- a/library/Vspheredb/MappedClass/PerformanceDescription.php
+++ b/library/Vspheredb/MappedClass/PerformanceDescription.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class PerformanceDescription
 {
     /** @var ElementDescription[] */
diff --git a/library/Vspheredb/MappedClass/PerformanceManager.php b/library/Vspheredb/MappedClass/PerformanceManager.php
index f88b514c..18403679 100644
--- a/library/Vspheredb/MappedClass/PerformanceManager.php
+++ b/library/Vspheredb/MappedClass/PerformanceManager.php
@@ -2,13 +2,15 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class PerformanceManager
 {
     /** @var PerformanceDescription */
     public $description;
 
-    /** @var PerfInterval[]|null */
+    /** @var ?PerfInterval[] */
     public $historicalInterval;
 
     /** @var PerfCounterInfo[] */
diff --git a/library/Vspheredb/MappedClass/PhysicalNic.php b/library/Vspheredb/MappedClass/PhysicalNic.php
index 494c8668..c4a5f285 100644
--- a/library/Vspheredb/MappedClass/PhysicalNic.php
+++ b/library/Vspheredb/MappedClass/PhysicalNic.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class PhysicalNic
 {
     /**
@@ -44,7 +46,7 @@ class PhysicalNic
      * The current link state of the physical network adapter. If this object
      * is not set, then the link is down.
      *
-     * @var PhysicalNicLinkInfo|null
+     * @var ?PhysicalNicLinkInfo
      */
     public $linkSpeed;
 
diff --git a/library/Vspheredb/MappedClass/PhysicalNicLinkInfo.php b/library/Vspheredb/MappedClass/PhysicalNicLinkInfo.php
index c919bd7d..acc525ec 100644
--- a/library/Vspheredb/MappedClass/PhysicalNicLinkInfo.php
+++ b/library/Vspheredb/MappedClass/PhysicalNicLinkInfo.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class PhysicalNicLinkInfo
 {
     /**
diff --git a/library/Vspheredb/MappedClass/PhysicalNicSpec.php b/library/Vspheredb/MappedClass/PhysicalNicSpec.php
index 82e76f58..b52aeeff 100644
--- a/library/Vspheredb/MappedClass/PhysicalNicSpec.php
+++ b/library/Vspheredb/MappedClass/PhysicalNicSpec.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class PhysicalNicSpec
 {
     /**
diff --git a/library/Vspheredb/MappedClass/PrivilegePolicyDef.php b/library/Vspheredb/MappedClass/PrivilegePolicyDef.php
index e8ca1bcc..9a497a6c 100644
--- a/library/Vspheredb/MappedClass/PrivilegePolicyDef.php
+++ b/library/Vspheredb/MappedClass/PrivilegePolicyDef.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class PrivilegePolicyDef
 {
     /** @var string */
diff --git a/library/Vspheredb/MappedClass/PropertyFilterSpec.php b/library/Vspheredb/MappedClass/PropertyFilterSpec.php
index 8f96287f..e8104a34 100644
--- a/library/Vspheredb/MappedClass/PropertyFilterSpec.php
+++ b/library/Vspheredb/MappedClass/PropertyFilterSpec.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * Specify the property data that is included in a filter.
  *
@@ -9,7 +11,7 @@
  * related managed objects in an inventory hierarchy - for example, to collect
  * updates from all virtual machines in a given folder.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class PropertyFilterSpec
 {
     /**
diff --git a/library/Vspheredb/MappedClass/PropertySpec.php b/library/Vspheredb/MappedClass/PropertySpec.php
index ec62d44b..82fba486 100644
--- a/library/Vspheredb/MappedClass/PropertySpec.php
+++ b/library/Vspheredb/MappedClass/PropertySpec.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * Within a PropertyFilterSpec, A PropertySpec specifies which properties
  * should be reported to the client for objects of the given managed object
@@ -15,7 +17,7 @@
  * of a RetrieveResult, where there may be an applicable PropertySpec in more
  * than one filter.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class PropertySpec
 {
     /**
diff --git a/library/Vspheredb/MappedClass/RetrieveOptions.php b/library/Vspheredb/MappedClass/RetrieveOptions.php
index d730919c..610c4f78 100644
--- a/library/Vspheredb/MappedClass/RetrieveOptions.php
+++ b/library/Vspheredb/MappedClass/RetrieveOptions.php
@@ -2,7 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class RetrieveOptions
 {
     /**
@@ -26,6 +26,7 @@ class RetrieveOptions
 
     /**
      * @param ?int $maxObjects
+     *
      * @return static
      */
     public static function create($maxObjects = null)
diff --git a/library/Vspheredb/MappedClass/RetrievePropertiesResponse.php b/library/Vspheredb/MappedClass/RetrievePropertiesResponse.php
index 07b71110..4ba915eb 100644
--- a/library/Vspheredb/MappedClass/RetrievePropertiesResponse.php
+++ b/library/Vspheredb/MappedClass/RetrievePropertiesResponse.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class RetrievePropertiesResponse
 {
     /** @var ObjectContent[] */
diff --git a/library/Vspheredb/MappedClass/RetrieveResult.php b/library/Vspheredb/MappedClass/RetrieveResult.php
index 3ee0172e..42074c21 100644
--- a/library/Vspheredb/MappedClass/RetrieveResult.php
+++ b/library/Vspheredb/MappedClass/RetrieveResult.php
@@ -2,12 +2,15 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+use ReturnTypeWillChange;
+
 /***
  * Result of RetrievePropertiesEx and ContinueRetrievePropertiesEx
  *
  * https://www.vmware.com/support/developer/converter-sdk/conv61_apireference/vmodl.query.PropertyCollector.RetrieveResult.html
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class RetrieveResult
 {
     /** @var ObjectContent[] retrieved objects */
@@ -28,7 +31,7 @@ class RetrieveResult
      *  _this => PropertyCollector (ref)
      * token => string
      *
-     * @var string|null
+     * @var ?string
      */
     public $token;
 
@@ -58,7 +61,7 @@ public function makeObjects()
         return $result;
     }
 
-    #[\ReturnTypeWillChange]
+    #[ReturnTypeWillChange]
     public function jsonSerialize()
     {
         $result = [];
diff --git a/library/Vspheredb/MappedClass/RunScriptAction.php b/library/Vspheredb/MappedClass/RunScriptAction.php
index 627062f9..c8919ef1 100644
--- a/library/Vspheredb/MappedClass/RunScriptAction.php
+++ b/library/Vspheredb/MappedClass/RunScriptAction.php
@@ -2,12 +2,14 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * This data object type specifies a script that is triggered by an alarm. You
  * can use any elements of the ActionParameter enumerated list as part of your
  * script to provide information available at runtime.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class RunScriptAction extends Action
 {
     /**
diff --git a/library/Vspheredb/MappedClass/SecurityError.php b/library/Vspheredb/MappedClass/SecurityError.php
index 8952a811..bafa13d1 100644
--- a/library/Vspheredb/MappedClass/SecurityError.php
+++ b/library/Vspheredb/MappedClass/SecurityError.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class SecurityError extends LocalizedMethodFault
 {
 }
diff --git a/library/Vspheredb/MappedClass/SelectionSpec.php b/library/Vspheredb/MappedClass/SelectionSpec.php
index 2405d3fc..d1936137 100644
--- a/library/Vspheredb/MappedClass/SelectionSpec.php
+++ b/library/Vspheredb/MappedClass/SelectionSpec.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * The SelectionSpec is the base type for data object types that specify what
  * additional objects to filter.
@@ -18,7 +20,7 @@
  *
  * Names are meaningful only within the same FilterSpec.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class SelectionSpec
 {
     /** @var ?string Name of the selection specification */
diff --git a/library/Vspheredb/MappedClass/ServiceContent.php b/library/Vspheredb/MappedClass/ServiceContent.php
index bc3addf1..4239f5f2 100644
--- a/library/Vspheredb/MappedClass/ServiceContent.php
+++ b/library/Vspheredb/MappedClass/ServiceContent.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
 
 /**
@@ -16,79 +17,79 @@
  * For this reason, use the method RetrieveServiceContent to retrieve the
  * ServiceContent object.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class ServiceContent
 {
     /** @var AboutInfo */
     public $about;
 
-    /** @var ManagedObjectReference|null to a HostLocalAccountManager */
+    /** @var ?ManagedObjectReference to a HostLocalAccountManager */
     public $accountManager;
 
-    /** @var ManagedObjectReference|null to a AlarmManager */
+    /** @var ?ManagedObjectReference to a AlarmManager */
     public $alarmManager;
 
-    /** @var ManagedObjectReference|null to a AuthorizationManager */
+    /** @var ?ManagedObjectReference to a AuthorizationManager */
     public $authorizationManager;
 
-    /** @var ManagedObjectReference|null to a CertificateManager - since vSphere API 6.0 */
+    /** @var ?ManagedObjectReference to a CertificateManager - since vSphere API 6.0 */
     public $certificateManager;
 
-    /** @var ManagedObjectReference|null to a ClusterProfileManager */
+    /** @var ?ManagedObjectReference to a ClusterProfileManager */
     public $clusterProfileManager;
 
-    /** @var ManagedObjectReference|null to a ProfileComplianceManager */
+    /** @var ?ManagedObjectReference to a ProfileComplianceManager */
     public $complianceManager;
 
-    /** @var ManagedObjectReference|null to a CustomFieldsManager */
+    /** @var ?ManagedObjectReference to a CustomFieldsManager */
     public $customFieldsManager;
 
-    /** @var ManagedObjectReference|null to a CustomizationSpecManager */
+    /** @var ?ManagedObjectReference to a CustomizationSpecManager */
     public $customizationSpecManager;
 
-    /** @var ManagedObjectReference|null to a CustomizationSpecManager */
+    /** @var ?ManagedObjectReference to a CustomizationSpecManager */
     public $datastoreNamespaceManager;
 
-    /** @var ManagedObjectReference|null to a DiagnosticManager */
+    /** @var ?ManagedObjectReference to a DiagnosticManager */
     public $diagnosticManager;
 
-    /** @var ManagedObjectReference|null to a DistributedVirtualSwitchManager */
+    /** @var ?ManagedObjectReference to a DistributedVirtualSwitchManager */
     public $dvSwitchManager;
 
-    /** @var ManagedObjectReference|null to a EventManager */
+    /** @var ?ManagedObjectReference to a EventManager */
     public $eventManager;
 
-    /** @var ManagedObjectReference|null to a ExtensionManager */
+    /** @var ?ManagedObjectReference to a ExtensionManager */
     public $extensionManager;
 
-    /** @var ManagedObjectReference|null to a FileManager */
+    /** @var ?ManagedObjectReference to a FileManager */
     public $fileManager;
 
-    /** @var ManagedObjectReference|null to a GuestOperationsManager */
+    /** @var ?ManagedObjectReference to a GuestOperationsManager */
     public $guestOperationsManager;
 
-    /** @var ManagedObjectReference|null to a HostProfileManager */
+    /** @var ?ManagedObjectReference to a HostProfileManager */
     public $hostProfileManager;
 
-    /** @var ManagedObjectReference|null to a IoFilterManager - since vSphere API 6.0 */
+    /** @var ?ManagedObjectReference to a IoFilterManager - since vSphere API 6.0 */
     public $ioFilterManager;
 
-    /** @var ManagedObjectReference|null to a IpPoolManager */
+    /** @var ?ManagedObjectReference to a IpPoolManager */
     public $ipPoolManager;
 
-    /** @var ManagedObjectReference|null to a LicenseManager */
+    /** @var ?ManagedObjectReference to a LicenseManager */
     public $licenseManager;
 
-    /** @var ManagedObjectReference|null to a LocalizationManager */
+    /** @var ?ManagedObjectReference to a LocalizationManager */
     public $localizationManager;
 
-    /** @var ManagedObjectReference|null to a OverheadMemoryManager - since vSphere API 6.0 */
+    /** @var ?ManagedObjectReference to a OverheadMemoryManager - since vSphere API 6.0 */
     public $overheadMemoryManager;
 
-    /** @var ManagedObjectReference|null to a OvfManager */
+    /** @var ?ManagedObjectReference to a OvfManager */
     public $ovfManager;
 
-    /** @var ManagedObjectReference|null to a PerformanceManager */
+    /** @var ?ManagedObjectReference to a PerformanceManager */
     public $perfManager;
 
     /** @var ManagedObjectReference to a PropertyCollector */
@@ -97,45 +98,45 @@ class ServiceContent
     /** @var ManagedObjectReference to a Folder */
     public $rootFolder;
 
-    /** @var ManagedObjectReference|null to a ScheduledTaskManager */
+    /** @var ?ManagedObjectReference to a ScheduledTaskManager */
     public $scheduledTaskManager;
 
-    /** @var ManagedObjectReference|null to a SearchIndex */
+    /** @var ?ManagedObjectReference to a SearchIndex */
     public $searchIndex;
 
-    /** @var ManagedObjectReference|null to a ServiceManager */
+    /** @var ?ManagedObjectReference to a ServiceManager */
     public $serviceManager;
 
-    /** @var ManagedObjectReference|null to a SessionManager */
+    /** @var ?ManagedObjectReference to a SessionManager */
     public $sessionManager;
 
-    /** @var ManagedObjectReference|null to a OptionManager */
+    /** @var ?ManagedObjectReference to a OptionManager */
     public $setting;
 
-    /** @var ManagedObjectReference|null to a HostSnmpSystem */
+    /** @var ?ManagedObjectReference to a HostSnmpSystem */
     public $snmpSystem;
 
-    /** @var ManagedObjectReference|null to a StorageResourceManager */
+    /** @var ?ManagedObjectReference to a StorageResourceManager */
     public $storageResourceManager;
 
-    /** @var ManagedObjectReference|null to a TaskManager */
+    /** @var ?ManagedObjectReference to a TaskManager */
     public $taskManager;
 
-    /** @var ManagedObjectReference|null to a UserDirectory */
+    /** @var ?ManagedObjectReference to a UserDirectory */
     public $userDirectory;
 
-    /** @var ManagedObjectReference|null to a ViewManager */
+    /** @var ?ManagedObjectReference to a ViewManager */
     public $viewManager;
 
-    /** @var ManagedObjectReference|null to a VirtualDiskManager */
+    /** @var ?ManagedObjectReference to a VirtualDiskManager */
     public $virtualDiskManager;
 
-    /** @var ManagedObjectReference|null to a VirtualizationManager */
+    /** @var ?ManagedObjectReference to a VirtualizationManager */
     public $virtualizationManager;
 
-    /** @var ManagedObjectReference|null to a VirtualMachineCompatibilityChecker */
+    /** @var ?ManagedObjectReference to a VirtualMachineCompatibilityChecker */
     public $vmCompatibilityChecker;
 
-    /** @var ManagedObjectReference|null to a VirtualMachineProvisioningChecker */
+    /** @var ?ManagedObjectReference to a VirtualMachineProvisioningChecker */
     public $vmProvisioningChecker;
 }
diff --git a/library/Vspheredb/MappedClass/SessionManager.php b/library/Vspheredb/MappedClass/SessionManager.php
index 7f692324..a50d8ae7 100644
--- a/library/Vspheredb/MappedClass/SessionManager.php
+++ b/library/Vspheredb/MappedClass/SessionManager.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * SessionManager
  *
@@ -9,7 +11,7 @@
  * clients, determining which clients are currently logged on, and forcing
  * clients to log off.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class SessionManager
 {
     /**
@@ -18,7 +20,7 @@ class SessionManager
      *
      * RequiredPrivilege: System.Anonymous
      *
-     * @var UserSession|null
+     * @var ?UserSession
      */
     public $currentSession;
 
@@ -45,7 +47,7 @@ class SessionManager
      *
      * RequiredPrivilege: System.Anonymous
      *
-     * @var array|null
+     * @var ?array
      */
     public $messageLocaleList;
 
@@ -54,7 +56,7 @@ class SessionManager
      *
      * RequiredPrivilege: Sessions.TerminateSession
      *
-     * @var UserSession[]|null
+     * @var ?UserSession[]
      */
     public $sessionList;
 
@@ -67,7 +69,7 @@ class SessionManager
      *
      * RequiredPrivilege: System.Anonymous
      *
-     * @var array|null
+     * @var ?array
      */
     public $supportedLocaleList;
 }
diff --git a/library/Vspheredb/MappedClass/Tag.php b/library/Vspheredb/MappedClass/Tag.php
index e93dedbc..70f16bf1 100644
--- a/library/Vspheredb/MappedClass/Tag.php
+++ b/library/Vspheredb/MappedClass/Tag.php
@@ -2,7 +2,9 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
-#[\AllowDynamicProperties]
+use AllowDynamicProperties;
+
+#[AllowDynamicProperties]
 class Tag
 {
     /** @var string The tag key in human readable form */
diff --git a/library/Vspheredb/MappedClass/TraversalSpec.php b/library/Vspheredb/MappedClass/TraversalSpec.php
index 616696e3..c0cdd012 100644
--- a/library/Vspheredb/MappedClass/TraversalSpec.php
+++ b/library/Vspheredb/MappedClass/TraversalSpec.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * The TraversalSpec data object type specifies how to derive a new set of
  * objects to add to the filter.
@@ -12,7 +14,7 @@
  *
  * This data object can also be named, using the "name" field in the base type.
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class TraversalSpec extends SelectionSpec
 {
     /** @var string Name of the property to use in order to select additional objects */
@@ -33,6 +35,7 @@ class TraversalSpec extends SelectionSpec
      * @param string $path
      * @param ?SelectionSpec[] $selectSet
      * @param ?boolean $skip
+     *
      * @return static
      */
     public static function create($name, $type, $path, ?array $selectSet = null, $skip = null)
diff --git a/library/Vspheredb/MappedClass/UserSession.php b/library/Vspheredb/MappedClass/UserSession.php
index d6499577..d8fb6be4 100644
--- a/library/Vspheredb/MappedClass/UserSession.php
+++ b/library/Vspheredb/MappedClass/UserSession.php
@@ -2,12 +2,14 @@
 
 namespace Icinga\Module\Vspheredb\MappedClass;
 
+use AllowDynamicProperties;
+
 /**
  * UserSession
  *
  * Information about a current user session
  */
-#[\AllowDynamicProperties]
+#[AllowDynamicProperties]
 class UserSession
 {
     /** @var int (long) Number of API invocations since the session started */
diff --git a/library/Vspheredb/MappedClass/VmEvent.php b/library/Vspheredb/MappedClass/VmEvent.php
index 2000cf6d..06b3f643 100644
--- a/library/Vspheredb/MappedClass/VmEvent.php
+++ b/library/Vspheredb/MappedClass/VmEvent.php
@@ -18,65 +18,37 @@ public function getDbData(VCenter $vCenter)
 
     protected function getDatacenterUuid(VCenter $vCenter)
     {
-        if ($this->datacenter) {
-            return $vCenter->makeBinaryGlobalUuid($this->datacenter->datacenter);
-        } else {
-            return null;
-        }
+        return $this->datacenter ? $vCenter->makeBinaryGlobalUuid($this->datacenter->datacenter) : null;
     }
 
     protected function getDatastoreUuid(VCenter $vCenter)
     {
-        if ($this->ds) {
-            return $vCenter->makeBinaryGlobalUuid($this->ds->datastore);
-        } else {
-            return null;
-        }
+        return $this->ds ? $vCenter->makeBinaryGlobalUuid($this->ds->datastore) : null;
     }
 
     protected function getComputeResourceUuid(VCenter $vCenter)
     {
-        if ($this->computeResource) {
-            return $vCenter->makeBinaryGlobalUuid($this->computeResource->computeResource);
-        } else {
-            return null;
-        }
+        return $this->computeResource ? $vCenter->makeBinaryGlobalUuid($this->computeResource->computeResource) : null;
     }
 
     protected function getHostUuid(VCenter $vCenter)
     {
-        if ($this->host) {
-            return $vCenter->makeBinaryGlobalUuid($this->host->host);
-        } else {
-            return null;
-        }
+        return $this->host ? $vCenter->makeBinaryGlobalUuid($this->host->host) : null;
     }
 
     protected function getVmUuid(VCenter $vCenter)
     {
-        if ($this->vm) {
-            return $vCenter->makeBinaryGlobalUuid($this->vm->vm);
-        } else {
-            return null;
-        }
+        return $this->vm ? $vCenter->makeBinaryGlobalUuid($this->vm->vm) : null;
     }
 
     protected function getConfigSpec(VCenter $vCenter)
     {
-        if (isset($this->configSpec)) {
-            return \json_encode($this->configSpec);
-        } else {
-            return null;
-        }
+        return isset($this->configSpec) ? json_encode($this->configSpec) : null;
     }
 
     protected function getConfigChanges(VCenter $vCenter)
     {
-        if (isset($this->configChanges)) {
-            return \json_encode($this->configChanges);
-        } else {
-            return null;
-        }
+        return isset($this->configChanges) ? json_encode($this->configChanges) : null;
     }
 
     protected function getVmEventDetails(VCenter $vCenter)
@@ -90,7 +62,7 @@ protected function getVmEventDetails(VCenter $vCenter)
             'vm_uuid'               => $this->getVmUuid($vCenter),
             'compute_resource_uuid' => $this->getComputeResourceUuid($vCenter),
             'config_spec'           => $this->getConfigSpec($vCenter),
-            'config_changes'        => $this->getConfigChanges($vCenter),
+            'config_changes'        => $this->getConfigChanges($vCenter)
         ];
     }
 }
diff --git a/library/Vspheredb/MappedClass/VmPoweredOffEvent.php b/library/Vspheredb/MappedClass/VmPoweredOffEvent.php
index 0a6530db..cd26f270 100644
--- a/library/Vspheredb/MappedClass/VmPoweredOffEvent.php
+++ b/library/Vspheredb/MappedClass/VmPoweredOffEvent.php
@@ -4,20 +4,24 @@
 
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Zend_Db_Adapter_Abstract as ZfDbAdapter;
+use Zend_Db_Adapter_Exception;
 
 class VmPoweredOffEvent extends VmEvent
 {
     /**
      * @param ZfDbAdapter $db
      * @param VCenter $vCenter
-     * @throws \Zend_Db_Adapter_Exception
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
     public function store(ZfDbAdapter $db, VCenter $vCenter)
     {
         parent::store($db, $vCenter);
 
-        $db->update('virtual_machine', [
-            'runtime_power_state' => 'poweredOff'
-        ], $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->vm->vm->_)));
+        $db->update(
+            'virtual_machine',
+            ['runtime_power_state' => 'poweredOff'],
+            $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->vm->vm->_))
+        );
     }
 }
diff --git a/library/Vspheredb/MappedClass/VmPoweredOnEvent.php b/library/Vspheredb/MappedClass/VmPoweredOnEvent.php
index 9e080c69..a5556f20 100644
--- a/library/Vspheredb/MappedClass/VmPoweredOnEvent.php
+++ b/library/Vspheredb/MappedClass/VmPoweredOnEvent.php
@@ -4,20 +4,24 @@
 
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Zend_Db_Adapter_Abstract as ZfDbAdapter;
+use Zend_Db_Adapter_Exception;
 
 class VmPoweredOnEvent extends VmEvent
 {
     /**
      * @param ZfDbAdapter $db
      * @param VCenter $vCenter
-     * @throws \Zend_Db_Adapter_Exception
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
     public function store(ZfDbAdapter $db, VCenter $vCenter)
     {
         parent::store($db, $vCenter);
 
-        $db->update('virtual_machine', [
-            'runtime_power_state' => 'poweredOn'
-        ], $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->vm->vm->_)));
+        $db->update(
+            'virtual_machine',
+            ['runtime_power_state' => 'poweredOn'],
+            $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->vm->vm->_))
+        );
     }
 }
diff --git a/library/Vspheredb/MappedClass/VmStartingEvent.php b/library/Vspheredb/MappedClass/VmStartingEvent.php
index 52590e15..216f9b76 100644
--- a/library/Vspheredb/MappedClass/VmStartingEvent.php
+++ b/library/Vspheredb/MappedClass/VmStartingEvent.php
@@ -4,21 +4,25 @@
 
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Zend_Db_Adapter_Abstract as ZfDbAdapter;
+use Zend_Db_Adapter_Exception;
 
 class VmStartingEvent extends VmEvent
 {
     /**
      * @param ZfDbAdapter $db
      * @param VCenter $vCenter
-     * @throws \Zend_Db_Adapter_Exception
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
     public function store(ZfDbAdapter $db, VCenter $vCenter)
     {
         parent::store($db, $vCenter);
 
         // We might see VmStartingEvent but no VmPoweredOffEvent
-        $db->update('virtual_machine', [
-            'runtime_power_state' => 'poweredOn'
-        ], $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->vm->vm->_)));
+        $db->update(
+            'virtual_machine',
+            ['runtime_power_state' => 'poweredOn'],
+            $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->vm->vm->_))
+        );
     }
 }
diff --git a/library/Vspheredb/MappedClass/VmSuspendedEvent.php b/library/Vspheredb/MappedClass/VmSuspendedEvent.php
index 57f4f44a..571ddf69 100644
--- a/library/Vspheredb/MappedClass/VmSuspendedEvent.php
+++ b/library/Vspheredb/MappedClass/VmSuspendedEvent.php
@@ -4,20 +4,24 @@
 
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Zend_Db_Adapter_Abstract as ZfDbAdapter;
+use Zend_Db_Adapter_Exception;
 
 class VmSuspendedEvent extends VmEvent
 {
     /**
      * @param ZfDbAdapter $db
      * @param VCenter $vCenter
-     * @throws \Zend_Db_Adapter_Exception
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
     public function store(ZfDbAdapter $db, VCenter $vCenter)
     {
         parent::store($db, $vCenter);
 
-        $db->update('virtual_machine', [
-            'runtime_power_state' => 'suspended'
-        ], $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->vm->vm->_)));
+        $db->update(
+            'virtual_machine',
+            ['runtime_power_state' => 'suspended'],
+            $db->quoteInto('uuid = ?', $vCenter->makeBinaryGlobalUuid($this->vm->vm->_))
+        );
     }
 }
diff --git a/library/Vspheredb/Monitoring/CheckPlugin.php b/library/Vspheredb/Monitoring/CheckPlugin.php
deleted file mode 100644
index 0192e253..00000000
--- a/library/Vspheredb/Monitoring/CheckPlugin.php
+++ /dev/null
@@ -1,183 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Monitoring;
-
-class CheckPlugin
-{
-    /** @var array */
-    protected $messages = [];
-
-    /** @var string|null */
-    protected $message;
-
-    /**
-     * @param $callable
-     */
-    protected function run($callable)
-    {
-        /** @var Command $this */
-        $this->loop()->futureTick(function () use ($callable) {
-            $result = null;
-            if (\is_callable($callable)) {
-                try {
-                    $result = $callable();
-                } catch (Exception $e) {
-                    $this->addProblem('UNKNOWN', $this->stripNonUtf8Characters($e->getMessage()));
-                } catch (\Throwable $e) {
-                    $this->addProblem('UNKNOWN', $this->stripNonUtf8Characters($e->getMessage()));
-                }
-            } else {
-                $this->addProblem('UNKNOWN', 'CheckPluginHelper requires a "callable"');
-            }
-
-            if ($result instanceof PromiseInterface) {
-                $result->then(function () {
-                    echo "as\n";
-                }, function (Exception $e) {
-                    var_dump('whut');
-                    $this->addProblem('UNKNOWN', $e->getMessage());
-                })->finally(function () {
-                    var_dump('Shut after res');
-                    $this->shutdown();
-                });
-            } else {
-                $this->shutdown();
-            }
-        });
-        $this->eventuallyStartMainLoop();
-    }
-
-    /**
-     * @param string $string
-     * @return string
-     */
-    protected function stripNonUtf8Characters($string)
-    {
-        return iconv('UTF-8', 'UTF-8//IGNORE', $string);
-    }
-
-    /**
-     * @param null $state
-     * @return mixed
-     */
-    protected function getStateName($state = null)
-    {
-        if ($state === null) {
-            return $this->stateNameMap[$this->state];
-        } else {
-            return $this->stateNameMap[$this->wantNumericState($state)];
-        }
-    }
-
-    /**
-     * @param int|string $state
-     * @param string $message
-     *
-     * @return $this
-     */
-    protected function addProblem(int|string $state, string $message): static
-    {
-        $this->raiseState($state);
-        $stateName = $this->getStateName($state);
-        $this->addMessage(sprintf(
-            '%s %s',
-            $this->getOutputScreen()->colorize("[$stateName]", $this->stateColors[$stateName]),
-            $message
-        ));
-
-        return $this;
-    }
-
-    protected function getOutputScreen()
-    {
-        if ($this->outputScreen === null) {
-            $this->outputScreen = Screen::factory();
-        }
-
-        return $this->outputScreen;
-    }
-
-    /**
-     * @param string $message
-     * @return $this
-     */
-    protected function addMessage($message)
-    {
-        $this->messages[] = $message;
-
-        return $this;
-    }
-
-    /**
-     * @param string $message
-     * @return $this
-     */
-    protected function prependMessage($message)
-    {
-        array_unshift($this->messages, $message);
-
-        return $this;
-    }
-
-    /**
-     * @param int|string $state
-     *
-     * @return $this
-     */
-    protected function raiseState(int|string $state): static
-    {
-        $state = $this->wantNumericState($state);
-        if ($this->sortingStateMap[$state] > $this->sortingStateMap[$this->state]) {
-            $this->state = $state;
-        }
-
-        return $this;
-    }
-
-    /**
-     * @return int
-     */
-    protected function getState()
-    {
-        return $this->state;
-    }
-
-    /**
-     * @param int|string $state
-     *
-     * @return int
-     */
-    protected function wantNumericState(int|string $state): int
-    {
-        if (is_int($state) || ctype_digit($state)) {
-            if (array_key_exists($state, $this->stateNameMap)) {
-                return (int) $state;
-            } else {
-                throw new InvalidArgumentException(sprintf('%d is not a valid numeric state', $state));
-            }
-        } else {
-            if (array_key_exists($state, $this->nameStateMap)) {
-                return $this->nameStateMap[$state];
-            } else {
-                throw new InvalidArgumentException(sprintf('%s is not a valid state name', $state));
-            }
-        }
-    }
-
-    protected function getMessages()
-    {
-        return $this->messages;
-    }
-
-    protected function shutdown()
-    {
-        $messages = $this->getMessages();
-        if (! empty($messages)) {
-            echo implode("\n", $messages) . "\n";
-        }
-        $this->loop()->addTimer(0.01, function () {
-            $this->loop()->stop();
-            exit($this->getState());
-        });
-    }
-}
diff --git a/library/Vspheredb/Monitoring/CheckPluginState.php b/library/Vspheredb/Monitoring/CheckPluginState.php
deleted file mode 100644
index eb89f121..00000000
--- a/library/Vspheredb/Monitoring/CheckPluginState.php
+++ /dev/null
@@ -1,160 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Monitoring;
-
-use InvalidArgumentException;
-
-class CheckPluginState
-{
-    public const OK = 0;
-    public const WARNING = 1;
-    public const CRITICAL = 2;
-    public const UNKNOWN = 3;
-
-    public const NAME_OK = 'OK';
-    public const NAME_WARNING = 'WARNING';
-    public const NAME_CRITICAL = 'CRITICAL';
-    public const NAME_UNKNOWN = 'UNKNOWN';
-
-    public const SORT_MAP = [
-        self::OK       => 0,
-        self::WARNING  => 1,
-        self::UNKNOWN  => 2,
-        self::CRITICAL => 3
-    ];
-
-    public const NAME_STATE_MAP = [
-        self::NAME_OK       => self::OK,
-        self::NAME_WARNING  => self::WARNING,
-        self::NAME_CRITICAL => self::CRITICAL,
-        self::NAME_UNKNOWN  => self::UNKNOWN,
-    ];
-    public const STATE_NAME_MAP = [
-        self::OK       => self::NAME_OK,
-        self::WARNING  => self::NAME_WARNING,
-        self::CRITICAL => self::NAME_CRITICAL,
-        self::UNKNOWN  => self::NAME_UNKNOWN,
-    ];
-
-    public const STATE_COLORS = [
-        self::OK      => 'green',
-        self::WARNING => 'brown',
-        self::CRITICAL => 'red',
-        self::UNKNOWN => 'purple',
-    ];
-
-    /** @var int */
-    protected $state = 0;
-
-    public function __construct($state = self::OK)
-    {
-        $this->setState($state);
-    }
-
-    public function setState($state)
-    {
-        $this->state = self::wantNumericState($state);
-    }
-
-    /**
-     * @param CheckPluginState|int|string $state
-     *
-     * @return void
-     */
-    public function raiseState(CheckPluginState|int|string $state): void
-    {
-        if ($state instanceof CheckPluginState) {
-            $state = $state->getState();
-        } else {
-            $state = self::wantNumericState($state);
-        }
-        if (self::SORT_MAP[$state] > self::SORT_MAP[$this->getState()]) {
-            $this->state = $state;
-        }
-    }
-
-    public function isProblem(): bool
-    {
-        return $this->getState() !== 0;
-    }
-
-    public static function compare(CheckPluginState $left, CheckPluginState $right): int
-    {
-        $left = self::SORT_MAP[$left->getState()];
-        $right = self::SORT_MAP[$right->getState()];
-        return $left === $right ? 0 : ($left < $right ? -1 : 1);
-    }
-
-    public static function getBest(CheckPluginState ...$states): CheckPluginState
-    {
-        $formerState = array_shift($states);
-        if ($formerState === null) {
-            throw new \RuntimeException('Comparing an empty state list is not possible');
-        }
-        while ($state = array_shift($states)) {
-            if (self::compare($formerState, $state) === 1) {
-                $formerState = $state;
-            }
-        }
-
-        return $formerState;
-    }
-
-    public static function getWorst(CheckPluginState ...$states): CheckPluginState
-    {
-        $formerState = array_shift($states);
-        if ($formerState === null) {
-            throw new \RuntimeException('Comparing an empty state list is not possible');
-        }
-        while ($state = array_shift($states)) {
-            if (self::compare($formerState, $state) === -1) {
-                $formerState = $state;
-            }
-        }
-
-        return $formerState;
-    }
-
-    public function getName(): string
-    {
-        return self::STATE_NAME_MAP[self::wantNumericState($this->getState())];
-    }
-
-    public function getExitCode(): int
-    {
-        return $this->state;
-    }
-
-    public function getColor(): string
-    {
-        return self::STATE_COLORS[$this->state];
-    }
-
-    protected function getState(): int
-    {
-        return $this->state;
-    }
-
-    /**
-     * @param string|int $state
-     *
-     * @return int
-     */
-    protected static function wantNumericState(string|int $state): int
-    {
-        if (is_int($state) || ctype_digit($state)) {
-            if (array_key_exists($state, self::STATE_NAME_MAP)) {
-                return (int) $state;
-            } else {
-                throw new InvalidArgumentException(sprintf('%d is not a valid numeric state', $state));
-            }
-        } else {
-            $state = strtoupper($state);
-            if (array_key_exists($state, self::NAME_STATE_MAP)) {
-                return self::NAME_STATE_MAP[$state];
-            } else {
-                throw new InvalidArgumentException(sprintf('%s is not a valid state name', $state));
-            }
-        }
-    }
-}
diff --git a/library/Vspheredb/Monitoring/CheckResultInterface.php b/library/Vspheredb/Monitoring/CheckResultInterface.php
index fe1351c0..b784da6b 100644
--- a/library/Vspheredb/Monitoring/CheckResultInterface.php
+++ b/library/Vspheredb/Monitoring/CheckResultInterface.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\Monitoring;
 
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
+
 interface CheckResultInterface
 {
     public function getState(): CheckPluginState;
diff --git a/library/Vspheredb/Monitoring/CheckResultSet.php b/library/Vspheredb/Monitoring/CheckResultSet.php
index c8305fa4..2646af1e 100644
--- a/library/Vspheredb/Monitoring/CheckResultSet.php
+++ b/library/Vspheredb/Monitoring/CheckResultSet.php
@@ -2,33 +2,34 @@
 
 namespace Icinga\Module\Vspheredb\Monitoring;
 
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
+
 class CheckResultSet implements CheckResultInterface
 {
     public const NUMERATION_PREFIX = ' \\_ ';
 
-    /** @var string */
-    protected $name;
+    protected string $name;
 
     /** @var CheckResultInterface[] */
-    protected $results = [];
+    protected array $results = [];
 
-    protected $prependedOutput = '';
+    protected string $prependedOutput = '';
 
     public function __construct(string $name)
     {
         $this->name = $name;
     }
 
-    public function addResult(CheckResultInterface $result)
+    public function addResult(CheckResultInterface $result): void
     {
         $this->results[] = $result;
     }
 
     public function getState(): CheckPluginState
     {
-        $state = new CheckPluginState();
+        $state = CheckPluginState::OK;
         foreach ($this->results as $result) {
-            $state->raiseState($result->getState());
+            $state = $state->raise($result->getState());
         }
 
         return $state;
@@ -39,10 +40,10 @@ public function isEmpty(): bool
         return empty($this->results);
     }
 
-    public function getOutput($prefix = ''): string
+    public function getOutput(string $prefix = ''): string
     {
         $indent = strlen($prefix . self::NUMERATION_PREFIX . '[');
-        $lines = [sprintf('%s[%s] %s', $prefix, $this->getState()->getName(), $this->name)];
+        $lines = [sprintf('%s[%s] %s', $prefix, $this->getState()->name, $this->name)];
         if ($this->prependedOutput !== '') {
             $lines[] = $this->indent($this->prependedOutput, $indent - 4);
         }
@@ -57,7 +58,7 @@ public function getOutput($prefix = ''): string
                     '%s%s[%s] %s',
                     $prefix,
                     self::NUMERATION_PREFIX,
-                    $result->getState()->getName(),
+                    $result->getState()->name,
                     $this->indentAllButFirstLine($result->getOutput(), $indent)
                 );
             }
@@ -66,7 +67,7 @@ public function getOutput($prefix = ''): string
         return implode(PHP_EOL, $lines);
     }
 
-    public function prependOutput(string $output)
+    public function prependOutput(string $output): void
     {
         $this->prependedOutput .= $output;
     }
@@ -74,6 +75,7 @@ public function prependOutput(string $output)
     protected function indentAllButFirstLine(string $string, int $spaces): string
     {
         $lines = explode(PHP_EOL, rtrim($string));
+
         return array_shift($lines) . $this->indent(implode(PHP_EOL, $lines), $spaces);
     }
 
@@ -83,11 +85,7 @@ protected function indent(string $string, int $spaces): string
         $output = '';
         $prefix = str_repeat(' ', $spaces);
         foreach ($lines as $line) {
-            if ($output === '') {
-                $output .= "$prefix$line";
-            } else {
-                $output .= "\n$prefix$line";
-            }
+            $output .= $output === '' ? "$prefix$line" : "\n$prefix$line";
         }
 
         return "$output"; // Hint: "$output\n" would be "correcter"
diff --git a/library/Vspheredb/Monitoring/CheckRunner.php b/library/Vspheredb/Monitoring/CheckRunner.php
index d2805246..c05da24b 100644
--- a/library/Vspheredb/Monitoring/CheckRunner.php
+++ b/library/Vspheredb/Monitoring/CheckRunner.php
@@ -7,12 +7,11 @@
 use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
-use Icinga\Module\Vspheredb\DbObject\Datastore;
-use Icinga\Module\Vspheredb\DbObject\HostSystem;
-use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Definition\ObjectStateRuleSet;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Definition\RuleSetRegistry;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Definition\VMwareObjectStateRuleDefinition;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
 use Icinga\Module\Vspheredb\Monitoring\Rule\InheritedSettings;
 use Icinga\Module\Vspheredb\Monitoring\Rule\MonitoringRulesTree;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Settings;
@@ -22,24 +21,20 @@
 class CheckRunner
 {
     public const RULESET_NAME_PARAMETER = 'ruleset';
+
     public const RULE_NAME_PARAMETER = 'rule';
 
-    /** @var Db */
-    protected $db;
+    protected Db $db;
 
-    /** @var Screen */
-    protected $screen;
+    protected Screen $screen;
 
-    /** @var string */
-    protected $ruleSetName;
+    protected ?string $ruleSetName = null;
 
-    /** @var string */
-    protected $ruleName;
+    protected ?string $ruleName = null;
 
-    /** @var bool */
-    protected $inspect = false;
+    protected bool $inspect = false;
 
-    protected $preloadedTrees = [];
+    protected array $preloadedTrees = [];
 
     public function __construct(Db $db)
     {
@@ -66,22 +61,22 @@ public function enableInspection(bool $inspect = true): void
     }
 
     /**
-     * @param string $type
+     * @param ObjectType $type
      *
      * @return void
      */
-    public function preloadTreeFor(string $type): void
+    public function preloadTreeFor(ObjectType $type): void
     {
-        $this->preloadedTrees[$type] = new MonitoringRulesTree($this->db, $type);
+        $this->preloadedTrees[$type->value] = new MonitoringRulesTree($this->db, $type->value);
     }
 
     public function check(BaseDbObject $object): CheckResultSet
     {
-        $type = self::getCheckTypeForObject($object);
+        $type = ObjectType::fromDbObject($object);
         $registry = $this->getRegistry();
         $settings = $this->getSettingsForObject($object, $registry, $type);
 
-        $all = new CheckResultSet(sprintf('%s, according configured rules', $this->getTypeLabelForObject($object)));
+        $all = new CheckResultSet(sprintf('%s, according configured rules', $type->label()));
         $final = $this->ruleSetName === null ? $all : null;
         foreach ($registry->getSets() as $set) {
             if ($settings->isDisabled($set)) {
@@ -123,7 +118,7 @@ public function check(BaseDbObject $object): CheckResultSet
                         throw new RuntimeException(sprintf(
                             'Cannot run checks for Rule "%s", it does not support "%s" objects',
                             $this->ruleName,
-                            $type
+                            $type->value
                         ));
                     }
                     continue;
@@ -150,9 +145,7 @@ public function check(BaseDbObject $object): CheckResultSet
                 try {
                     $results = $rule->checkObject($object, $ruleSettings);
                 } catch (Exception $e) {
-                    $results = [
-                        new SingleCheckResult(new CheckPluginState(CheckPluginState::UNKNOWN), $e->getMessage())
-                    ];
+                    $results = [new SingleCheckResult(CheckPluginState::UNKNOWN, $e->getMessage())];
                 }
                 foreach ($results as $result) {
                     $ruleResult->addResult($result);
@@ -168,11 +161,7 @@ public function check(BaseDbObject $object): CheckResultSet
 
     protected function getRegistry(): RuleSetRegistry
     {
-        if ($this->ruleSetName) {
-            return RuleSetRegistry::byName($this->ruleSetName);
-        } else {
-            return RuleSetRegistry::default();
-        }
+        return $this->ruleSetName ? RuleSetRegistry::byName($this->ruleSetName) : RuleSetRegistry::default();
     }
 
     /**
@@ -181,9 +170,9 @@ protected function getRegistry(): RuleSetRegistry
     protected function getSettingsForObject(
         BaseDbObject $object,
         RuleSetRegistry $registry,
-        string $type
+        ObjectType $type
     ): InheritedSettings {
-        $tree = $this->preloadedTrees[$type] ?? new MonitoringRulesTree($this->db, $type);
+        $tree = $this->preloadedTrees[$type->value] ?? new MonitoringRulesTree($this->db, $type->value);
         $settings = $tree->getInheritedSettingsFor($object);
         $settings->setInternalDefaults($registry);
 
@@ -192,20 +181,21 @@ protected function getSettingsForObject(
 
     /**
      * @param BaseDbObject $object
+     *
      * @return array<string, CheckResultSet>
      */
     public function checkForDb(BaseDbObject $object): array
     {
-        $type = self::getCheckTypeForObject($object);
+        $type = ObjectType::fromDbObject($object);
         $registry = $this->getRegistry();
         try {
             $settings = $this->getSettingsForObject($object, $registry, $type);
-        } catch (NotFoundError $e) {
+        } catch (NotFoundError) {
             // Fake Set with just a global state
             $ruleSetResult = new CheckResultSet((new ObjectStateRuleSet())->getLabel());
             $ruleResult = new CheckResultSet((new VMwareObjectStateRuleDefinition())->getLabel());
             $ruleResult->addResult(new SingleCheckResult(
-                new CheckPluginState(CheckPluginState::UNKNOWN),
+                CheckPluginState::UNKNOWN,
                 'Could not find the related Managed Object, please check my vCenter permissions'
             ));
             $ruleSetResult->addResult($ruleResult);
@@ -241,32 +231,6 @@ public function checkForDb(BaseDbObject $object): array
         return $results;
     }
 
-    protected function getTypeLabelForObject(BaseDbObject $object): string
-    {
-        if ($object instanceof HostSystem) {
-            return 'Host System';
-        } elseif ($object instanceof VirtualMachine) {
-            return 'Virtual Machine';
-        } elseif ($object instanceof Datastore) {
-            return 'Datastore';
-        }
-
-        return 'Object';
-    }
-
-    public static function getCheckTypeForObject(BaseDbObject $object): string
-    {
-        if ($object instanceof HostSystem) {
-            return 'host';
-        } elseif ($object instanceof VirtualMachine) {
-            return 'vm';
-        } elseif ($object instanceof Datastore) {
-            return 'datastore';
-        }
-
-        throw new InvalidArgumentException('Check commands are not supported for ' . get_class($object));
-    }
-
     protected function light(string $string): string
     {
         return $this->screen->colorize($string, 'lightgray');
diff --git a/library/Vspheredb/Monitoring/Health/ApiConnectionInfo.php b/library/Vspheredb/Monitoring/Health/ApiConnectionInfo.php
index e2ee1ce8..73dd9e4e 100644
--- a/library/Vspheredb/Monitoring/Health/ApiConnectionInfo.php
+++ b/library/Vspheredb/Monitoring/Health/ApiConnectionInfo.php
@@ -6,6 +6,7 @@
 use Icinga\Module\Vspheredb\Polling\ApiConnection;
 use Icinga\Module\Vspheredb\Polling\ServerInfo;
 use InvalidArgumentException;
+use stdClass;
 
 class ApiConnectionInfo implements JsonSerialization
 {
@@ -16,22 +17,26 @@ class ApiConnectionInfo implements JsonSerialization
         ApiConnection::STATE_FAILING   => 'CRITICAL',
         ApiConnection::STATE_STOPPED   => 'WARNING',
         ApiConnection::STATE_STOPPING  => 'WARNING',
-        'unknown' => 'CRITICAL',
+        'unknown'                      => 'CRITICAL'
     ];
 
-    /** @var string */
-    public $state;
-    /** @var string */
-    public $server;
-    /** @var int */
-    public $serverId;
-    /** @var int */
-    public $vCenterId;
-    /** @var ?int */
-    public $connectionId;
-    /** @var ?string */
-    public $lastErrorMessage = null;
+    public string $state;
 
+    public string $server;
+
+    public int $serverId;
+
+    public int $vCenterId;
+
+    public ?int $connectionId = null;
+
+    public ?string $lastErrorMessage = null;
+
+    /**
+     * @param ApiConnection $connection
+     *
+     * @return ApiConnectionInfo
+     */
     public static function fromConnectionInfo(ApiConnection $connection): ApiConnectionInfo
     {
         $server = $connection->getServerInfo();
@@ -47,7 +52,7 @@ public static function fromConnectionInfo(ApiConnection $connection): ApiConnect
         return $info;
     }
 
-    public static function fromSerialization($any): ApiConnectionInfo
+    public static function fromSerialization(mixed $any): ApiConnectionInfo
     {
         $self = new ApiConnectionInfo(
             $any->state,
@@ -64,6 +69,12 @@ public static function fromSerialization($any): ApiConnectionInfo
         return $self;
     }
 
+    /**
+     * @param ServerInfo $server
+     * @param string $message
+     *
+     * @return ApiConnectionInfo
+     */
     public static function failingConnectionForServer(ServerInfo $server, string $message): ApiConnectionInfo
     {
         return new ApiConnectionInfo(
@@ -75,18 +86,24 @@ public static function failingConnectionForServer(ServerInfo $server, string $me
         );
     }
 
+    /**
+     * @return string
+     */
     public function getIcingaState(): string
     {
         return self::STATE_MAP[$this->state];
     }
 
-    public function jsonSerialize(): \stdClass
+    /**
+     * @return stdClass
+     */
+    public function jsonSerialize(): stdClass
     {
         $self = (object) [
             'state' => $this->state,
             'server' => $this->server,
             'serverId' => $this->serverId,
-            'vCenterId' => $this->vCenterId,
+            'vCenterId' => $this->vCenterId
         ];
 
         if ($this->lastErrorMessage) {
@@ -99,6 +116,15 @@ public function jsonSerialize(): \stdClass
         return $self;
     }
 
+    /**
+     * @param string $state
+     * @param string $server
+     * @param int $serverId
+     * @param int $vCenterId
+     * @param ?string $lastErrorMessage
+     *
+     * @throws InvalidArgumentException
+     */
     protected function __construct(
         string $state,
         string $server,
diff --git a/library/Vspheredb/Monitoring/Health/ServerConnectionInfo.php b/library/Vspheredb/Monitoring/Health/ServerConnectionInfo.php
index 6ace3fde..d7083929 100644
--- a/library/Vspheredb/Monitoring/Health/ServerConnectionInfo.php
+++ b/library/Vspheredb/Monitoring/Health/ServerConnectionInfo.php
@@ -11,15 +11,20 @@
  */
 class ServerConnectionInfo
 {
-    /** @var ?ApiConnectionInfo */
-    public $apiConnection = null;
-    /** @var bool */
-    public $enabled;
-    /** @var string */
-    public $serverName;
-    /** @var bool */
-    protected $configured;
+    public ?ApiConnectionInfo $apiConnection = null;
 
+    public bool $enabled;
+
+    public string $serverName;
+
+    protected bool $configured;
+
+    /**
+     * @param string $serverName
+     * @param bool $enabled
+     * @param bool $configured
+     * @param ?ApiConnectionInfo $apiConnection
+     */
     public function __construct(
         string $serverName,
         bool $enabled,
@@ -34,12 +39,17 @@ public function __construct(
 
     /**
      * @param ?ApiConnectionInfo $apiConnection
+     *
+     * @return void
      */
     public function setApiConnection(?ApiConnectionInfo $apiConnection): void
     {
         $this->apiConnection = $apiConnection;
     }
 
+    /**
+     * @return string
+     */
     public function getState(): string
     {
         if ($this->enabled) {
@@ -53,6 +63,9 @@ public function getState(): string
         return 'disabled';
     }
 
+    /**
+     * @return string
+     */
     public function getIcingaState(): string
     {
         if ($this->enabled) {
diff --git a/library/Vspheredb/Monitoring/Health/VCenterInfo.php b/library/Vspheredb/Monitoring/Health/VCenterInfo.php
index 75f137d4..839934e1 100644
--- a/library/Vspheredb/Monitoring/Health/VCenterInfo.php
+++ b/library/Vspheredb/Monitoring/Health/VCenterInfo.php
@@ -7,33 +7,38 @@
 use gipfl\ZfDbStore\NotFoundError;
 use Icinga\Module\Vspheredb\Db\DbUtil;
 use Ramsey\Uuid\Uuid;
-use Ramsey\Uuid\UuidInterface;
+use Zend_Db_Adapter_Abstract;
+use Zend_Db_Select;
 
 class VCenterInfo
 {
     // Hint: these should become readonly properties
 
-    /** @var UuidInterface */
-    public $uuid;
-    /** @var int */
-    public $id;
-    /** @var string */
-    public $name;
-    /** @var string */
-    public $software;
-    /** @var string */
-    public $softwareName;
-    /** @var string */
-    public $softwareVersion;
-
-    public static function fromDbRow($row): VCenterInfo
+    public ?string $uuid = null;
+
+    public ?int $id = null;
+
+    public ?string $name = null;
+
+    public ?string $software = null;
+
+    public ?string $softwareName = null;
+
+    public ?string $softwareVersion = null;
+
+    /**
+     * @param object $row
+     *
+     * @return VCenterInfo
+     */
+    public static function fromDbRow(object $row): VCenterInfo
     {
         $self = new static();
         $self->id = (int) $row->id;
         $self->uuid = Uuid::fromBytes(DbUtil::binaryResult($row->uuid))->toString();
-        $self->software = \sprintf(
+        $self->software = sprintf(
             '%s (%s)',
-            \preg_replace('/^VMware /', '', $row->software_name),
+            preg_replace('/^VMware /', '', $row->software_name),
             $row->software_version
         );
         $self->softwareName = $row->software_name;
@@ -44,27 +49,29 @@ public static function fromDbRow($row): VCenterInfo
     }
 
     /**
-     * @var Adapter|\Zend_Db_Adapter_Abstract $db
-     * @return Select|\Zend_Db_Select
+     * @param Zend_Db_Adapter_Abstract|Adapter $db
+     *
+     * @return Select|Zend_Db_Select
      */
-    public static function prepareQuery($db)
+    public static function prepareQuery(Zend_Db_Adapter_Abstract|Adapter $db): Select|Zend_Db_Select
     {
         $columns = [
             'uuid'             => 'vc.instance_uuid',
             'id'               => 'vc.id',
             'name'             => 'vc.name',
             'software_name'    => 'vc.api_name',
-            'software_version' => 'vc.version',
+            'software_version' => 'vc.version'
         ];
 
         return $db->select()->from(['vc' => 'vcenter'], $columns)->order('name');
     }
 
     /**
-     * @var Adapter|\Zend_Db_Adapter_Abstract $db
+     * @param Zend_Db_Adapter_Abstract|Adapter $db
+     *
      * @return VCenterInfo[]
      */
-    public static function fetchAll($db): array
+    public static function fetchAll(Zend_Db_Adapter_Abstract|Adapter $db): array
     {
         $result = [];
         /** @var object{id: int} $row */
@@ -77,11 +84,13 @@ public static function fetchAll($db): array
 
     /**
      * @param int $id
+     * @param Zend_Db_Adapter_Abstract|Adapter $db
+     *
      * @return VCenterInfo
+     *
      * @throws NotFoundError
-     * @var Adapter|\Zend_Db_Adapter_Abstract $db
      */
-    public static function fetchOne(int $id, $db): VCenterInfo
+    public static function fetchOne(int $id, Zend_Db_Adapter_Abstract|Adapter $db): VCenterInfo
     {
         if ($row = $db->fetchRow(static::prepareQuery($db)->where('id = ?', $id))) {
             return VCenterInfo::fromDbRow($row);
diff --git a/library/Vspheredb/Monitoring/MonitoringRuleLookup.php b/library/Vspheredb/Monitoring/MonitoringRuleLookup.php
deleted file mode 100644
index 37a1b23e..00000000
--- a/library/Vspheredb/Monitoring/MonitoringRuleLookup.php
+++ /dev/null
@@ -1,57 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Monitoring;
-
-use Icinga\Module\Vspheredb\DbObject\Datastore;
-use Icinga\Module\Vspheredb\DbObject\HostSystem;
-use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
-use InvalidArgumentException;
-
-class MonitoringRuleLookup
-{
-    public static function getUrlForObjectType($objectType): string
-    {
-        switch ($objectType) {
-            case 'VirtualMachine':
-                return 'vspheredb/vm';
-            case 'HostSystem':
-                return 'vspheredb/host';
-            case 'Datastore':
-                return 'vspheredb/datastore';
-        }
-
-        throw new InvalidArgumentException('Unsupported object type: ' . $objectType);
-    }
-
-    /**
-     * @param $objectType
-     * @return string|VirtualMachine|HostSystem|Datastore
-     */
-    public static function getClassForObjectType($objectType): string
-    {
-        switch ($objectType) {
-            case 'VirtualMachine':
-                return VirtualMachine::class;
-            case 'HostSystem':
-                return HostSystem::class;
-            case 'Datastore':
-                return Datastore::class;
-        }
-
-        throw new InvalidArgumentException('Unsupported object type: ' . $objectType);
-    }
-
-    public static function getTableForObjectType($objectType): string
-    {
-        switch ($objectType) {
-            case 'VirtualMachine':
-                return 'virtual_machine';
-            case 'HostSystem':
-                return 'host_system';
-            case 'Datastore':
-                return 'datastore';
-        }
-
-        throw new InvalidArgumentException('Unsupported object type: ' . $objectType);
-    }
-}
diff --git a/library/Vspheredb/Monitoring/PersistedRuleProblems.php b/library/Vspheredb/Monitoring/PersistedRuleProblems.php
index efb23d14..ea2abdde 100644
--- a/library/Vspheredb/Monitoring/PersistedRuleProblems.php
+++ b/library/Vspheredb/Monitoring/PersistedRuleProblems.php
@@ -12,9 +12,12 @@
 use Icinga\Module\Vspheredb\DbObject\ManagedObject;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\DbObject\VmQuickStats;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
 use Icinga\Module\Vspheredb\Monitoring\Rule\MonitoringRuleSet;
 use Icinga\Module\Vspheredb\Util;
 use Throwable;
+use Zend_Db_Adapter_Exception;
 
 class PersistedRuleProblems
 {
@@ -41,13 +44,13 @@ public function refresh()
         $objects = ManagedObject::loadAll($this->db, null, 'uuid');
         $datastores = Datastore::loadAll($this->db, null, 'uuid');
         $this->presetManagedObjects($datastores, $objects);
-        $this->checkObjects($datastores, 'datastore');
+        $this->checkObjects($datastores, ObjectType::DATASTORE);
         unset($datastores);
 
         HostQuickStats::preloadAll($this->db);
         $hosts = HostSystem::loadAll($this->db, null, 'uuid');
         $this->presetManagedObjects($hosts, $objects);
-        $this->checkObjects($hosts, 'host');
+        $this->checkObjects($hosts, ObjectType::HOST_SYSTEM);
 
         VmQuickStats::preloadAll($this->db);
         // TODO: Preload Disk Usage and Snapshots
@@ -70,7 +73,7 @@ public function refresh()
                 $vm->setManagedObject($objects[$uuid]);
             }
         }
-        $this->checkObjects($vms, 'vm');
+        $this->checkObjects($vms, ObjectType::VIRTUAL_MACHINE);
 
         unset($objects);
         unset($hosts);
@@ -115,10 +118,13 @@ protected function fetchCurrentProblems(): array
 
     /**
      * @param BaseDbObject[] $objects
+     * @param ObjectType $folderType
+     *
      * @return void
-     * @throws \Zend_Db_Adapter_Exception
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
-    protected function checkObjects(array $objects, $folderType)
+    protected function checkObjects(array $objects, ObjectType $folderType): void
     {
         $runner = new CheckRunner($this->db);
         $runner->preloadTreeFor($folderType);
@@ -145,7 +151,7 @@ protected function checkObjects(array $objects, $folderType)
         }
     }
 
-    protected function rememberCheckedObjects($checked)
+    protected function rememberCheckedObjects(array $checked): void
     {
         foreach ($checked as $uuid => $names) {
             foreach ($names as $name => $true) {
@@ -156,8 +162,10 @@ protected function rememberCheckedObjects($checked)
 
     /**
      * @param array<string,array<string,CheckResultSet>> $results
+     *
      * @return array
-     * @throws \Zend_Db_Adapter_Exception
+     *
+     * @throws Zend_Db_Adapter_Exception
      */
     protected function processCheckedObjects(array $results): array
     {
@@ -167,48 +175,48 @@ protected function processCheckedObjects(array $results): array
         foreach ($results as $uuid => $objectResults) {
             foreach ($objectResults as $name => $resultSet) {
                 $now = Util::currentTimestamp();
-                $state = $resultSet->getState()->getName();
+                $state = $resultSet->getState();
                 $checked[$uuid][$name] = true;
                 if (isset($current[$uuid][$name])) {
                     $formerRow = $current[$uuid][$name];
                     $formerState = $formerRow->current_state;
-                    if ($formerState === $state) {
+                    if ($formerState === $state->name) {
                         continue;
                     }
                     $where = $db->quoteInto('uuid = ?', DbUtil::quoteBinaryCompat($uuid, $db))
                         . $db->quoteInto(' AND rule_name = ?', $name);
-                    if ($state === CheckPluginState::NAME_OK) {
+                    if ($state === CheckPluginState::OK) {
                         $db->delete(self::TABLE, $where);
                     } else {
                         $db->update(self::TABLE, [
-                            'current_state' => $state,
-                            'ts_changed_ms' => $now,
+                            'current_state' => $state->name,
+                            'ts_changed_ms' => $now
                         ], $where);
                     }
                     $db->insert(self::HISTORY_TABLE, [
                         'uuid'           => $uuid,
-                        'current_state'  => $state,
+                        'current_state'  => $state->name,
                         'former_state'   => $formerState,
                         'rule_name'      => $name,
                         'ts_changed_ms'  => $now,
-                        'output'         => $resultSet->getOutput(),
+                        'output'         => $resultSet->getOutput()
                     ]);
-                } elseif ($state !== CheckPluginState::NAME_OK) {
+                } elseif ($state !== CheckPluginState::OK) {
                     $db->insert(self::TABLE, [
                         'uuid'           => $uuid,
-                        'current_state'  => $state,
+                        'current_state'  => $state->name,
                         'rule_name'      => $name,
                         'ts_created_ms'  => $now,
-                        'ts_changed_ms'  => $now,
+                        'ts_changed_ms'  => $now
                     ]);
                     // emit new problem
                     $db->insert(self::HISTORY_TABLE, [
                         'uuid'           => $uuid,
-                        'current_state'  => $state,
-                        'former_state'   => CheckPluginState::NAME_OK, // null?
+                        'current_state'  => $state->name,
+                        'former_state'   => CheckPluginState::OK->name, // null?
                         'rule_name'      => $name,
                         'ts_changed_ms'  => $now,
-                        'output'         => $resultSet->getOutput(),
+                        'output'         => $resultSet->getOutput()
                     ]);
                 }
             }
@@ -217,7 +225,7 @@ protected function processCheckedObjects(array $results): array
         return $checked;
     }
 
-    protected function dropObsoleteRows()
+    protected function dropObsoleteRows(): void
     {
         $db = $this->db->getDbAdapter();
         $db->beginTransaction();
@@ -233,11 +241,11 @@ protected function dropObsoleteRows()
                         $db->delete(self::TABLE, $where);
                         $db->insert(self::HISTORY_TABLE, [
                             'uuid'           => $uuid,
-                            'current_state'  => CheckPluginState::NAME_OK,
+                            'current_state'  => CheckPluginState::OK->name,
                             'former_state'   => $row->current_state,
                             'rule_name'      => $name,
                             'ts_changed_ms'  => $now,
-                            'output'         => null,
+                            'output'         => null
                         ]);
                     }
                 }
@@ -254,7 +262,7 @@ protected function dropObsoleteRows()
         }
     }
 
-    protected function deleteOutdatedHistoryRows()
+    protected function deleteOutdatedHistoryRows(): void
     {
         $db = $this->db->getDbAdapter();
         $expiration = 86400 * 90;
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/ActiveMemoryUsageRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/ActiveMemoryUsageRuleDefinition.php
index 57b948fc..7c801fb2 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/ActiveMemoryUsageRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/ActiveMemoryUsageRuleDefinition.php
@@ -7,9 +7,7 @@
 
 class ActiveMemoryUsageRuleDefinition extends MemoryUsageRuleDefinition
 {
-    public const SUPPORTED_OBJECT_TYPES = [
-        ObjectType::VIRTUAL_MACHINE,
-    ];
+    public const SUPPORTED_OBJECT_TYPES = [ObjectType::VIRTUAL_MACHINE];
 
     public static function getIdentifier(): string
     {
@@ -21,7 +19,7 @@ public function getLabel(): string
         return $this->translate('Active Memory Usage');
     }
 
-    protected function getUsedMemory(BaseDbObject $quickStats)
+    protected function getUsedMemory(BaseDbObject $quickStats): int
     {
         return $quickStats->get('guest_memory_usage_mb') * MemoryUsageHelper::MEGA_BYTE;
     }
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/ComputeResourceUsageRuleSet.php b/library/Vspheredb/Monitoring/Rule/Definition/ComputeResourceUsageRuleSet.php
index 48584c02..5d01cf10 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/ComputeResourceUsageRuleSet.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/ComputeResourceUsageRuleSet.php
@@ -7,7 +7,7 @@ class ComputeResourceUsageRuleSet extends MonitoringRuleSetDefinition
     public const RULE_CLASSES = [
         CpuUsageRuleDefinition::class,
         MemoryUsageRuleDefinition::class,
-        ActiveMemoryUsageRuleDefinition::class,
+        ActiveMemoryUsageRuleDefinition::class
     ];
 
     public function getLabel(): string
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/ConfigurationPolicyRuleSet.php b/library/Vspheredb/Monitoring/Rule/Definition/ConfigurationPolicyRuleSet.php
index b5df1410..5e1d68b8 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/ConfigurationPolicyRuleSet.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/ConfigurationPolicyRuleSet.php
@@ -4,9 +4,7 @@
 
 class ConfigurationPolicyRuleSet extends MonitoringRuleSetDefinition
 {
-    public const RULE_CLASSES = [
-        GuestUtilitiesRuleDefinition::class,
-    ];
+    public const RULE_CLASSES = [GuestUtilitiesRuleDefinition::class];
 
     public function getLabel(): string
     {
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/CpuUsageRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/CpuUsageRuleDefinition.php
index d0adbe54..c8f875c7 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/CpuUsageRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/CpuUsageRuleDefinition.php
@@ -9,7 +9,7 @@
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\DbObject\VmQuickStats;
 use Icinga\Module\Vspheredb\Format;
-use Icinga\Module\Vspheredb\Monitoring\CheckPluginState;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Settings;
 use Icinga\Module\Vspheredb\Monitoring\SingleCheckResult;
@@ -18,7 +18,7 @@ class CpuUsageRuleDefinition extends MonitoringRuleDefinition
 {
     public const SUPPORTED_OBJECT_TYPES = [
         ObjectType::HOST_SYSTEM,
-        ObjectType::VIRTUAL_MACHINE,
+        ObjectType::VIRTUAL_MACHINE
     ];
 
     public static function getIdentifier(): string
@@ -58,12 +58,12 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
                 $mhzSingleCpu = 2000;
             }
         }
-        $state = new CheckPluginState();
+        $state = CheckPluginState::OK;
         $mhzUsed = $quickStats->get('overall_cpu_usage');
         $mhzCapacity = $mhzSingleCpu * $cpuCount;
         $mhzFree = $mhzCapacity - $mhzUsed;
         if ($mhzCapacity === 0) {
-            $state->raiseState(CheckPluginState::UNKNOWN);
+            $state = $state->raise(CheckPluginState::UNKNOWN);
             return [
                 new SingleCheckResult($state, sprintf(
                     '%s used, but got ZERO capacity (%d CPUs, %s per CPU)',
@@ -86,11 +86,11 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
 
         $min = $settings->get('warning_if_less_than_percent_free');
         if ($min && ($percentFree < (float) $min)) {
-            $state->raiseState(CheckPluginState::WARNING);
+            $state = $state->raise(CheckPluginState::WARNING);
         }
         $min = $settings->get('critical_if_less_than_percent_free');
         if ($min && ($percentFree < (float) $min)) {
-            $state->raiseState(CheckPluginState::CRITICAL);
+            $state = $state->raise(CheckPluginState::CRITICAL);
         }
 
         return [
@@ -103,12 +103,12 @@ public function getParameters(): array
         return [
             'warning_if_less_than_percent_free' => ['number', [
                 'label' => $this->translate('Raise Warning with less than X percent free'),
-                'placeholder' => '30',
+                'placeholder' => '30'
             ]],
             'critical_if_less_than_percent_free' => ['number', [
                 'label' => $this->translate('Raise Critical with less than X percent free'),
-                'placeholder' => '10',
-            ]],
+                'placeholder' => '10'
+            ]]
         ];
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/DatastoreHealthRuleSet.php b/library/Vspheredb/Monitoring/Rule/Definition/DatastoreHealthRuleSet.php
index f0bd146e..0354acc8 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/DatastoreHealthRuleSet.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/DatastoreHealthRuleSet.php
@@ -4,9 +4,7 @@
 
 class DatastoreHealthRuleSet extends MonitoringRuleSetDefinition
 {
-    public const RULE_CLASSES = [
-        DatastoreUsageRuleDefinition::class,
-    ];
+    public const RULE_CLASSES = [DatastoreUsageRuleDefinition::class];
 
     public function getLabel(): string
     {
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/DatastoreUsageRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/DatastoreUsageRuleDefinition.php
index 39d2b331..cde16d9e 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/DatastoreUsageRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/DatastoreUsageRuleDefinition.php
@@ -8,9 +8,7 @@
 
 class DatastoreUsageRuleDefinition extends MonitoringRuleDefinition
 {
-    public const SUPPORTED_OBJECT_TYPES = [
-        ObjectType::DATASTORE,
-    ];
+    public const SUPPORTED_OBJECT_TYPES = [ObjectType::DATASTORE];
 
     public static function getIdentifier(): string
     {
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/DiskHealthRuleSet.php b/library/Vspheredb/Monitoring/Rule/Definition/DiskHealthRuleSet.php
index 6cc66e9a..28e0fee1 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/DiskHealthRuleSet.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/DiskHealthRuleSet.php
@@ -6,7 +6,7 @@ class DiskHealthRuleSet extends MonitoringRuleSetDefinition
 {
     public const RULE_CLASSES = [
         SnapshotsRuleDefinition::class,
-        DiskUsageRuleDefinition::class,
+        DiskUsageRuleDefinition::class
     ];
 
     public function getLabel(): string
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/DiskUsageRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/DiskUsageRuleDefinition.php
index 77e9ad22..87f0dc57 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/DiskUsageRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/DiskUsageRuleDefinition.php
@@ -9,9 +9,7 @@
 
 class DiskUsageRuleDefinition extends MonitoringRuleDefinition
 {
-    public const SUPPORTED_OBJECT_TYPES = [
-        ObjectType::VIRTUAL_MACHINE,
-    ];
+    public const SUPPORTED_OBJECT_TYPES = [ObjectType::VIRTUAL_MACHINE];
 
     public static function getIdentifier(): string
     {
@@ -65,7 +63,7 @@ protected function filterMatchesPath(string $filterString, string $path): bool
 
     protected static function stringMatches(string $filterString, string $string): bool
     {
-        if (strpos($filterString, '*') === false) {
+        if (! str_contains($filterString, '*')) {
             return $string === $filterString;
         }
 
@@ -85,7 +83,7 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
         $disks = $db->fetchAll($db->select()->from('vm_disk_usage', [
             'disk_path',
             'capacity',
-            'free_space',
+            'free_space'
         ])->where('vm_disk_usage.vm_uuid = ?', $object->getConnection()->quoteBinary($object->get('uuid'))));
 
         $instanceSettings = [];
@@ -114,12 +112,12 @@ public function getParameters(): array
         return [
             'disk_path_filter' => ['text', [
                 'label' => $this->translate('Apply to specific disks only'),
-                'placeholder' => 'e.g. C:\\, /var/*, C:\\|D:\\|E:\\',
+                'placeholder' => 'e.g. C:\\, /var/*, C:\\|D:\\|E:\\'
             ]],
             'disk_path_ignore' => ['text', [
                 'label' => $this->translate('Ignore specific disks'),
-                'placeholder' => 'e.g. C:\\, */volume-subpaths/*|/var/lib/kubelet/*',
-            ]],
+                'placeholder' => 'e.g. C:\\, */volume-subpaths/*|/var/lib/kubelet/*'
+            ]]
         ] + MemoryUsageHelper::getParameters();
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/GuestUtilitiesRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/GuestUtilitiesRuleDefinition.php
index 32a06b5d..bce66a1b 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/GuestUtilitiesRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/GuestUtilitiesRuleDefinition.php
@@ -4,7 +4,7 @@
 
 use gipfl\IcingaWeb2\Link;
 use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
-use Icinga\Module\Vspheredb\Monitoring\CheckPluginState as State;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState as State;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\MonitoringStateTrigger as Trigger;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Settings;
@@ -16,9 +16,7 @@
 
 class GuestUtilitiesRuleDefinition extends MonitoringRuleDefinition
 {
-    public const SUPPORTED_OBJECT_TYPES = [
-        ObjectType::VIRTUAL_MACHINE,
-    ];
+    public const SUPPORTED_OBJECT_TYPES = [ObjectType::VIRTUAL_MACHINE];
 
     public static function getIdentifier(): string
     {
@@ -33,26 +31,26 @@ public function getLabel(): string
     public function getSuggestedSettings(): array
     {
         return [
-            'on_vcenter_complaint' => Trigger::RAISE_WARNING,
-            'on_not_installed'     => Trigger::RAISE_WARNING,
-            'on_not_running'       => Trigger::RAISE_WARNING,
-            'version_2147483647'   => Trigger::IGNORE,
+            'on_vcenter_complaint' => Trigger::RAISE_WARNING->value,
+            'on_not_installed'     => Trigger::RAISE_WARNING->value,
+            'on_not_running'       => Trigger::RAISE_WARNING->value,
+            'version_2147483647'   => Trigger::IGNORE->value
         ];
     }
 
     public function checkObject(BaseDbObject $object, Settings $settings): array
     {
-        $state = new State();
+        $state = State::OK;
         $version = $object->get('guest_tools_version');
         $versionInfo = '';
 
         if ($version === '2147483647') {
             $versionInfo = "v$version";
-            $state->raiseState(Trigger::getMonitoringState($settings->get('version_2147483647')));
+            $state = $state->raise(Trigger::nullableFrom($settings->get('version_2147483647'))->monitoringState());
         } elseif (
             $version !== null && (
-            preg_match('/^([89])(\d{1})(\d{2})$/', $version, $m)
-            || preg_match('/^(1\d)(\d{1})(\d{2})$/', $version, $m)
+                preg_match('/^([89])(\d{1})(\d{2})$/', $version, $m)
+                || preg_match('/^(1\d)(\d{1})(\d{2})$/', $version, $m)
             )
         ) {
             $version = sprintf('%d.%d.%d', $m[1], $m[2], $m[3]);
@@ -60,27 +58,28 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
             $required = $settings->get('warning_if_less_than');
             if ($required && version_compare($version, $required) < 0) {
                 $versionInfo .= ", less than $required";
-                $state->raiseState(State::WARNING);
+                $state = $state->raise(State::WARNING);
             }
             $required = $settings->get('critical_if_less_than');
             if ($required && version_compare($version, $required) < 0) {
                 $versionInfo .= ", less than $required";
-                $state->raiseState(State::CRITICAL);
+                $state = $state->raise(State::CRITICAL);
             }
         }
 
         switch ($object->get('guest_tools_status')) {
             case 'toolsNotInstalled':
                 $message = 'Guest Tools are NOT installed';
-                $state->raiseState(Trigger::getMonitoringState($settings->get('on_not_installed')));
+                $state = $state->raise(Trigger::nullableFrom($settings->get('on_not_installed'))->monitoringState());
                 break;
             case 'toolsNotRunning':
                 $message = sprintf('Guest Tools (%s) are NOT running', $versionInfo);
-                $state->raiseState(Trigger::getMonitoringState($settings->get('on_not_running')));
+                $state = $state->raise(Trigger::nullableFrom($settings->get('on_not_running'))->monitoringState());
                 break;
             case 'toolsOld':
                 $message = sprintf('Guest Tools (%s) are old (considered outdated by VMware)', $versionInfo);
-                $state->raiseState(Trigger::getMonitoringState($settings->get('on_vcenter_complaint')));
+                $state = $state->raise(Trigger::nullableFrom($settings->get('on_vcenter_complaint'))
+                    ->monitoringState());
                 break;
             case 'toolsOk':
                 $message = sprintf('Guest Tools (%s) are up to date and running', $versionInfo);
@@ -90,29 +89,27 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
                 $message = 'Guest Tools status is now known';
         }
 
-        return [
-            new SingleCheckResult($state, $message)
-        ];
+        return [new SingleCheckResult($state, $message)];
     }
 
     public function getParameters(): array
     {
         return [
             'on_vcenter_complaint' => ['state_trigger', [
-                'label' => $this->translate('When the vCenter says "outdated"'),
+                'label' => $this->translate('When the vCenter says "outdated"')
             ]],
             'on_not_installed' => ['state_trigger', [
-                'label' => $this->translate('When not installed'),
+                'label' => $this->translate('When not installed')
             ]],
             'on_not_running' => ['state_trigger', [
-                'label' => $this->translate('When installed, but not running'),
+                'label' => $this->translate('When installed, but not running')
             ]],
             'version_2147483647' => ['state_trigger', [
                 'label' => $this->translate('On version 2147483647'),
                 'description' => Html::sprintf(
                     $this->translate('Please read %s'),
                     Link::create('KB 51988', 'https://kb.vmware.com/s/article/51988')
-                ),
+                )
             ]],
             'warning_if_less_than' => ['text', [
                 'label' => $this->translate('Raise Warning for versions lower than'),
@@ -121,7 +118,7 @@ public function getParameters(): array
             'critical_if_less_than' => ['text', [
                 'label' => $this->translate('Raise Critical for versions lower than'),
                 'placeholder' => '00.0.00'
-            ]],
+            ]]
         ];
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/MemoryUsageHelper.php b/library/Vspheredb/Monitoring/Rule/Definition/MemoryUsageHelper.php
index 8a35131a..7dbafcbd 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/MemoryUsageHelper.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/MemoryUsageHelper.php
@@ -3,8 +3,8 @@
 namespace Icinga\Module\Vspheredb\Monitoring\Rule\Definition;
 
 use gipfl\Translation\StaticTranslator;
-use Icinga\Module\Vspheredb\Monitoring\CheckPluginState;
-use Icinga\Module\Vspheredb\Monitoring\CheckPluginState as State;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState as State;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Settings;
 use Icinga\Module\Vspheredb\Monitoring\SingleCheckResult;
 use Icinga\Util\Format;
@@ -19,9 +19,9 @@ public static function prepareState(
         int $capacity,
         ?string $instanceName = null
     ): SingleCheckResult {
-        $state = new State();
+        $state = State::OK;
         if ($capacity === 0) {
-            $state->raiseState(CheckPluginState::UNKNOWN);
+            $state = $state->raise(CheckPluginState::UNKNOWN);
             return new SingleCheckResult($state, sprintf(
                 '%s free, but got ZERO capacity',
                 Format::bytes($free, Format::STANDARD_IEC)
@@ -41,36 +41,34 @@ public static function prepareState(
             $output = "$instanceName has $output";
         }
 
-        $percentState = new State();
+        $percentState = State::OK;
         $min = $settings->get('warning_if_less_than_percent_free');
         if ($min && ($percentFree < (float) $min)) {
-            $percentState->raiseState(State::WARNING);
+            $percentState = $percentState->raise(State::WARNING);
         }
         $min = $settings->get('critical_if_less_than_percent_free');
         if ($min && ($percentFree < (float) $min)) {
-            $percentState->raiseState(State::CRITICAL);
+            $percentState = $percentState->raise(State::CRITICAL);
         }
 
-        $mbState = new State();
+        $mbState = State::OK;
         $mbFree = $free / self::MEGA_BYTE;
         $min = $settings->get('warning_if_less_than_mbytes_free');
         if ($min && ($mbFree < (float) $min)) {
-            $mbState->raiseState(State::WARNING);
+            $mbState = $mbState->raise(State::WARNING);
         }
         $min = $settings->get('critical_if_less_than_mbytes_free');
         if ($min && ($mbFree < (float) $min)) {
-            $mbState->raiseState(State::CRITICAL);
+            $mbState = $mbState->raise(State::CRITICAL);
         }
 
         if ($mbState->isProblem() || $percentState->isProblem()) {
-            if ($settings->get('threshold_precedence') === 'worst_wins') {
-                $state->raiseState(State::getWorst($percentState, $mbState));
-            } else {
-                $state->raiseState(State::getBest($percentState, $mbState));
-            }
+            $state = $settings->get('threshold_precedence') === 'worst_wins'
+                ? $state->raise(State::getWorst($percentState, $mbState))
+                : $state->raise(State::getBest($percentState, $mbState));
         } else {
-            $state->raiseState($percentState);
-            $state->raiseState($mbState);
+            $state = $state->raise($percentState);
+            $state = $state->raise($mbState);
         }
 
         return new SingleCheckResult($state, $output);
@@ -85,25 +83,25 @@ public static function getParameters(): array
                 'options' => [
                     '' => $t->translate('- please choose -'),
                     'best_wins' => $t->translate('Better state wins'),
-                    'worst_wins' => $t->translate('Worse state wins'),
-                ],
+                    'worst_wins' => $t->translate('Worse state wins')
+                ]
             ]],
             'warning_if_less_than_percent_free' => ['number', [
                 'label' => $t->translate('Raise Warning with less than X percent free'),
-                'placeholder' => '5',
+                'placeholder' => '5'
             ]],
             'critical_if_less_than_percent_free' => ['number', [
                 'label' => $t->translate('Raise Critical with less than X percent free'),
-                'placeholder' => '2',
+                'placeholder' => '2'
             ]],
             'warning_if_less_than_mbytes_free' => ['number', [
                 'label' => $t->translate('Raise Warning with less than X MBytes free'),
-                'placeholder' => '500',
+                'placeholder' => '500'
             ]],
             'critical_if_less_than_mbytes_free' => ['number', [
                 'label' => $t->translate('Raise Critical with less than X MBytes free'),
-                'placeholder' => '100',
-            ]],
+                'placeholder' => '100'
+            ]]
         ];
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/MemoryUsageRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/MemoryUsageRuleDefinition.php
index 7b6a57dd..9af4d203 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/MemoryUsageRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/MemoryUsageRuleDefinition.php
@@ -9,12 +9,13 @@
 use Icinga\Module\Vspheredb\DbObject\VmQuickStats;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Settings;
+use InvalidArgumentException;
 
 class MemoryUsageRuleDefinition extends MonitoringRuleDefinition
 {
     public const SUPPORTED_OBJECT_TYPES = [
         ObjectType::HOST_SYSTEM,
-        ObjectType::VIRTUAL_MACHINE,
+        ObjectType::VIRTUAL_MACHINE
     ];
 
     public static function getIdentifier(): string
@@ -34,7 +35,12 @@ public function getInternalDefaults(): array
         ];
     }
 
-    protected function getUsedMemory(BaseDbObject $quickStats)
+    /**
+     * @param BaseDbObject $quickStats
+     *
+     * @return int
+     */
+    protected function getUsedMemory(BaseDbObject $quickStats): int
     {
         if ($quickStats instanceof VmQuickStats) {
             return $quickStats->get('host_memory_usage_mb') * MemoryUsageHelper::MEGA_BYTE;
@@ -53,7 +59,7 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
             $quickStats = VmQuickStats::loadFor($object);
             $capacity = $object->get('hardware_memorymb') * MemoryUsageHelper::MEGA_BYTE;
         } else {
-            throw new \InvalidArgumentException('Cannot load QuickStats for ' . get_class($object));
+            throw new InvalidArgumentException('Cannot load QuickStats for ' . get_class($object));
         }
         $used = $this->getUsedMemory($quickStats);
         $free = $capacity - $used;
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/MonitoringRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/MonitoringRuleDefinition.php
index 864c7d10..0208edb9 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/MonitoringRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/MonitoringRuleDefinition.php
@@ -7,6 +7,7 @@
 use Icinga\Module\Vspheredb\Monitoring\Rule\Settings;
 use Icinga\Module\Vspheredb\Monitoring\SingleCheckResult;
 use ipl\I18n\Translation;
+use RuntimeException;
 
 use function in_array;
 
@@ -14,10 +15,13 @@ abstract class MonitoringRuleDefinition
 {
     use Translation;
 
+    /** @var ObjectType[] */
     public const SUPPORTED_OBJECT_TYPES = [];
 
     abstract public function getLabel(): string;
+
     abstract public static function getIdentifier(): string;
+
     abstract public function getParameters(): array;
 
     public static function isMultiInstanceRule(): bool
@@ -25,7 +29,7 @@ public static function isMultiInstanceRule(): bool
         return false;
     }
 
-    public static function supportsObjectType(string $objectType): bool
+    public static function supportsObjectType(ObjectType $objectType): bool
     {
         return in_array($objectType, static::SUPPORTED_OBJECT_TYPES, true);
     }
@@ -33,6 +37,7 @@ public static function supportsObjectType(string $objectType): bool
     /**
      * @param BaseDbObject $object
      * @param Settings $settings
+     *
      * @return SingleCheckResult[]
      */
     public function checkObject(BaseDbObject $object, Settings $settings): array
@@ -60,14 +65,14 @@ public function getSuggestedSettings(): array
         return [];
     }
 
-    protected function assertSupportedObject($object)
+    protected function assertSupportedObject($object): void
     {
-        $type = ObjectType::getDbClassType(get_class($object));
+        $type = ObjectType::fromDbObject($object);
         if (!static::supportsObjectType($type)) {
-            throw new \RuntimeException(sprintf(
+            throw new RuntimeException(sprintf(
                 "'%s' is not supported. Supported: %s",
-                $type,
-                implode(', ', static::SUPPORTED_OBJECT_TYPES)
+                $type->value,
+                implode(', ', array_map(fn (ObjectType $t) => $t->value, static::SUPPORTED_OBJECT_TYPES))
             ));
         }
     }
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/MonitoringRuleSetDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/MonitoringRuleSetDefinition.php
index e67eceb9..2d9eb71c 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/MonitoringRuleSetDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/MonitoringRuleSetDefinition.php
@@ -8,11 +8,11 @@ abstract class MonitoringRuleSetDefinition
 {
     use Translation;
 
-    /** @var string[]|MonitoringRuleDefinition[] Type hint, these are class names */
+    /** @var class-string<MonitoringRuleDefinition>[] */
     public const RULE_CLASSES = [];
 
-    /** @var MonitoringRuleDefinition[]|null */
-    protected $rules = null;
+    /** @var ?MonitoringRuleDefinition[] */
+    protected ?array $rules = null;
 
     /**
      * @return MonitoringRuleDefinition[]
@@ -30,6 +30,7 @@ public function getRules(): array
     }
 
     abstract public function getLabel(): string;
+
     abstract public static function getIdentifier(): string;
 
     /**
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/ObjectStateRuleSet.php b/library/Vspheredb/Monitoring/Rule/Definition/ObjectStateRuleSet.php
index 529bc0a0..000dec50 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/ObjectStateRuleSet.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/ObjectStateRuleSet.php
@@ -6,7 +6,7 @@ class ObjectStateRuleSet extends MonitoringRuleSetDefinition
 {
     public const RULE_CLASSES = [
         VMwareObjectStateRuleDefinition::class,
-        PowerStateRuleDefinition::class,
+        PowerStateRuleDefinition::class
     ];
 
     public function getLabel(): string
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/PowerStateRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/PowerStateRuleDefinition.php
index a9c0d4bf..b2e7dad6 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/PowerStateRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/PowerStateRuleDefinition.php
@@ -8,7 +8,7 @@
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\DbObject\VmQuickStats;
-use Icinga\Module\Vspheredb\Monitoring\CheckPluginState;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\MonitoringStateTrigger;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Settings;
@@ -19,7 +19,7 @@ class PowerStateRuleDefinition extends MonitoringRuleDefinition
 {
     public const SUPPORTED_OBJECT_TYPES = [
         ObjectType::HOST_SYSTEM,
-        ObjectType::VIRTUAL_MACHINE,
+        ObjectType::VIRTUAL_MACHINE
     ];
 
     public static function getIdentifier(): string
@@ -37,9 +37,7 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
         if ($object instanceof VirtualMachine) {
             $what = 'Virtual Machine';
             if ($object->get('template') === 'y') {
-                return [
-                    new SingleCheckResult(new CheckPluginState(), 'This is a VM template')
-                ];
+                return [new SingleCheckResult(CheckPluginState::OK, 'This is a VM template')];
             }
         } elseif ($object instanceof HostSystem) {
             $what = 'Host System';
@@ -48,19 +46,15 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
         }
 
         $powerState = $object->get('runtime_power_state');
-        if ($powerState === 'poweredOn') {
-            $state = new CheckPluginState(CheckPluginState::OK);
-        } else {
-            $state = MonitoringStateTrigger::getMonitoringState($settings->get("trigger_on_$powerState"));
-        }
+        $state = $powerState === 'poweredOn'
+            ? CheckPluginState::OK
+            : MonitoringStateTrigger::nullableFrom($settings->get("trigger_on_$powerState"))->monitoringState();
         $message = $this->getStatusMessageForPowerState($powerState, $what);
 
-        $results = [
-            new SingleCheckResult($state, $message)
-        ];
+        $results = [new SingleCheckResult($state, $message)];
 
         if ($powerState === 'poweredOn') {
-            $uptimeState = new CheckPluginState();
+            $uptimeState = CheckPluginState::OK;
             if ($object instanceof HostSystem) {
                 $stats = HostQuickStats::loadFor($object);
             } else {
@@ -75,13 +69,13 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
 
             foreach (
                 [
-                'warning_for_uptime_less_than_seconds'  => CheckPluginState::WARNING,
-                'critical_for_uptime_less_than_seconds' => CheckPluginState::CRITICAL,
+                    'warning_for_uptime_less_than_seconds'  => CheckPluginState::WARNING->value,
+                    'critical_for_uptime_less_than_seconds' => CheckPluginState::CRITICAL->value
                 ] as $setting => $errorState
             ) {
                 $min = $settings->get($setting);
                 if ($min) {
-                    $this->checkMin($uptimeState, $uptime, $min, $errorState, $info);
+                    $uptimeState = $this->checkMin($uptimeState, $uptime, $min, $errorState, $info);
                 }
             }
 
@@ -91,13 +85,13 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
             }
             foreach (
                 [
-                 'warning_for_uptime_greater_than_days'  => CheckPluginState::WARNING,
-                 'critical_for_uptime_greater_than_days' => CheckPluginState::CRITICAL,
+                    'warning_for_uptime_greater_than_days'  => CheckPluginState::WARNING->value,
+                    'critical_for_uptime_greater_than_days' => CheckPluginState::CRITICAL->value
                 ] as $setting => $errorState
             ) {
                 $min = $settings->get($setting);
                 if ($min) {
-                    $this->checkMax($uptimeState, $uptime, $min * 86400, $errorState, $info);
+                    $uptimeState = $this->checkMax($uptimeState, $uptime, $min * 86400, $errorState, $info);
                 }
             }
 
@@ -113,49 +107,56 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
         return $results;
     }
 
-    protected function checkMax(CheckPluginState $uptimeState, $value, $threshold, $errorState, &$info)
-    {
-        if ($threshold) {
-            if ($value >= $threshold) {
-                $uptimeState->raiseState($errorState);
-                $info = sprintf('>= %s ago', DateFormatter::formatDuration($threshold));
-            }
+    protected function checkMax(
+        CheckPluginState $uptimeState,
+        int $value,
+        int $threshold,
+        int $errorState,
+        ?string &$info
+    ): CheckPluginState {
+        if ($value >= $threshold) {
+            $info = sprintf('>= %s ago', DateFormatter::formatDuration($threshold));
+
+            return $uptimeState->raise(CheckPluginState::from($errorState));
         }
+
+        return $uptimeState;
     }
 
-    protected function checkMin(CheckPluginState $uptimeState, $value, $threshold, $errorState, &$info)
-    {
-        if ($threshold) {
-            if ($value < $threshold) {
-                $uptimeState->raiseState($errorState);
-                $info = sprintf('less than %s ago', DateFormatter::formatDuration($threshold));
-            }
+    protected function checkMin(
+        CheckPluginState $uptimeState,
+        int $value,
+        int $threshold,
+        int $errorState,
+        ?string &$info
+    ): CheckPluginState {
+        if ($value < $threshold) {
+            $info = sprintf('less than %s ago', DateFormatter::formatDuration($threshold));
+
+            return $uptimeState->raise(CheckPluginState::from($errorState));
         }
+
+        return $uptimeState;
     }
 
-    protected function getStatusMessageForPowerState($state, $what): string
+    protected function getStatusMessageForPowerState(string $state, string $what): string
     {
-        switch ($state) {
-            case 'poweredOff':
-                return "$what has been powered off";
-            case 'suspended':
-                return "$what has been suspended";
-            case 'unknown':
-                return "$what power state is unknown, might be disconnected";
-            case 'poweredOn':
-                return "$what is powered on";
-        }
-
-        throw new InvalidArgumentException("'$state' is not a known power state");
+        return match ($state) {
+            'poweredOff' => "$what has been powered off",
+            'suspended'  => "$what has been suspended",
+            'unknown'    => "$what power state is unknown, might be disconnected",
+            'poweredOn'  => "$what is powered on",
+            default      => throw new InvalidArgumentException("'$state' is not a known power state")
+        };
     }
 
     public function getInternalDefaults(): array
     {
         return [
-            'trigger_on_poweredOff' => MonitoringStateTrigger::RAISE_CRITICAL,
-            'trigger_on_suspended'  => MonitoringStateTrigger::RAISE_CRITICAL,
-            'trigger_on_unknown'    => MonitoringStateTrigger::RAISE_UNKNOWN,
-            'warning_for_uptime_less_than' => 900,
+            'trigger_on_poweredOff'        => MonitoringStateTrigger::RAISE_CRITICAL->value,
+            'trigger_on_suspended'         => MonitoringStateTrigger::RAISE_CRITICAL->value,
+            'trigger_on_unknown'           => MonitoringStateTrigger::RAISE_UNKNOWN->value,
+            'warning_for_uptime_less_than' => 900
         ];
     }
 
@@ -163,31 +164,31 @@ public function getParameters(): array
     {
         return [
             'trigger_on_poweredOff' => ['state_trigger', [
-                'label' => $this->translate('When powered off'),
+                'label' => $this->translate('When powered off')
             ]],
             'trigger_on_suspended' => ['state_trigger', [
-                'label' => $this->translate('When suspended'),
+                'label' => $this->translate('When suspended')
             ]],
             'trigger_on_unknown' => ['state_trigger', [
                 'label'       => $this->translate('When unknown'),
-                'description' => $this->translate('Might be disconnected'),
+                'description' => $this->translate('Might be disconnected')
             ]],
             'warning_for_uptime_less_than' => ['number', [
                 'label'       => $this->translate('Raise WARNING for uptime less than'),
-                'description' => $this->translate('Please provide the uptime in seconds'),
+                'description' => $this->translate('Please provide the uptime in seconds')
             ]],
             'critical_for_uptime_less_than' => ['number', [
                 'label'       => $this->translate('Raise CRITICAL for uptime less than'),
-                'description' => $this->translate('Please provide the uptime in seconds'),
+                'description' => $this->translate('Please provide the uptime in seconds')
             ]],
             'warning_for_uptime_greater_than_days' => ['number', [
                 'label'       => $this->translate('Raise WARNING for uptime greater than'),
-                'description' => $this->translate('Please provide the uptime in days'),
+                'description' => $this->translate('Please provide the uptime in days')
             ]],
             'critical_for_uptime_greater_than_days' => ['number', [
                 'label'       => $this->translate('Raise CRITICAL for uptime greater than'),
-                'description' => $this->translate('Please provide the uptime in days'),
-            ]],
+                'description' => $this->translate('Please provide the uptime in days')
+            ]]
         ];
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/RuleSetRegistry.php b/library/Vspheredb/Monitoring/Rule/Definition/RuleSetRegistry.php
index 609782a3..396726aa 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/RuleSetRegistry.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/RuleSetRegistry.php
@@ -3,20 +3,22 @@
 namespace Icinga\Module\Vspheredb\Monitoring\Rule\Definition;
 
 use gipfl\Json\JsonSerialization;
+use InvalidArgumentException;
 use RuntimeException;
+use stdClass;
 
 class RuleSetRegistry implements JsonSerialization
 {
-    protected static $allSets = [
+    protected static array $allSets = [
         ObjectStateRuleSet::class,
         ComputeResourceUsageRuleSet::class,
         DiskHealthRuleSet::class,
         DatastoreHealthRuleSet::class,
-        ConfigurationPolicyRuleSet::class,
+        ConfigurationPolicyRuleSet::class
     ];
 
     /** @var MonitoringRuleSetDefinition[] */
-    protected $sets = [];
+    protected array $sets = [];
 
     /**
      * @param string[]|MonitoringRuleSetDefinition[] $sets
@@ -36,7 +38,7 @@ public function getSets(): array
         return $this->sets;
     }
 
-    public static function byName(string $name): RuleSetRegistry
+    public static function byName(string $name): static
     {
         /** @var string|MonitoringRuleSetDefinition $class */
         foreach (self::$allSets as $class) {
@@ -45,15 +47,15 @@ public static function byName(string $name): RuleSetRegistry
             }
         }
 
-        throw new \InvalidArgumentException("There is no Rule Set named '$name'");
+        throw new InvalidArgumentException("There is no Rule Set named '$name'");
     }
 
-    public static function default(): RuleSetRegistry
+    public static function default(): static
     {
         return new static(self::$allSets);
     }
 
-    public function loadSet(string $class)
+    public function loadSet(string $class): void
     {
         $set = new $class();
         /** @var string $name */
@@ -65,12 +67,12 @@ public function loadSet(string $class)
         $this->sets[$name] = $set;
     }
 
-    public static function fromSerialization($any): RuleSetRegistry
+    public static function fromSerialization(mixed $any): static
     {
         return new static((array) $any);
     }
 
-    public function jsonSerialize(): \stdClass
+    public function jsonSerialize(): stdClass
     {
         $result = [];
         foreach ($this->sets as $set) {
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/SnapshotsRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/SnapshotsRuleDefinition.php
index ad792b00..75a0e6a2 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/SnapshotsRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/SnapshotsRuleDefinition.php
@@ -3,16 +3,14 @@
 namespace Icinga\Module\Vspheredb\Monitoring\Rule\Definition;
 
 use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
-use Icinga\Module\Vspheredb\Monitoring\CheckPluginState;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Settings;
 use Icinga\Module\Vspheredb\Monitoring\SingleCheckResult;
 
 class SnapshotsRuleDefinition extends MonitoringRuleDefinition
 {
-    public const SUPPORTED_OBJECT_TYPES = [
-        ObjectType::VIRTUAL_MACHINE,
-    ];
+    public const SUPPORTED_OBJECT_TYPES = [ObjectType::VIRTUAL_MACHINE];
 
     public static function getIdentifier(): string
     {
@@ -27,10 +25,10 @@ public function getLabel(): string
     public function getInternalDefaults(): array
     {
         return [
-            'warning_if_more_than'  => 1,
-            'critical_if_more_than' => 5,
-            'warning_if_older_than' => 7, // Days
-            'critical_if_older_than' => 30,
+            'warning_if_more_than'   => 1,
+            'critical_if_more_than'  => 5,
+            'warning_if_older_than'  => 7, // Days
+            'critical_if_older_than' => 30
         ];
     }
 
@@ -42,7 +40,7 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
             'cnt' => 'COUNT(*)',
             'ts_oldest' => 'FLOOR(MIN(ts_create) / 1000)'
         ])->where('vm_snapshot.vm_uuid = ?', $object->getConnection()->quoteBinary($object->get('uuid'))));
-        $state = new CheckPluginState();
+        $state = CheckPluginState::OK;
         $count = (int) $info->cnt;
 
         if ($count === 0) {
@@ -50,19 +48,19 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
         } else {
             $max = $settings->get('warning_if_more_than');
             if ($max && $count > $max) {
-                $state->raiseState(CheckPluginState::WARNING);
+                $state = $state->raise(CheckPluginState::WARNING);
             }
             $max = $settings->get('critical_if_more_than');
             if ($max && $count > $max) {
-                $state->raiseState(CheckPluginState::CRITICAL);
+                $state = $state->raise(CheckPluginState::CRITICAL);
             }
             $min = $settings->get('warning_if_older_than');
             if ($min && $info->ts_oldest < (time() - $min * 86400)) {
-                $state->raiseState(CheckPluginState::WARNING);
+                $state = $state->raise(CheckPluginState::WARNING);
             }
             $min = $settings->get('critical_if_older_than');
             if ($min && $info->ts_oldest < (time() - $min * 86400)) {
-                $state->raiseState(CheckPluginState::CRITICAL);
+                $state = $state->raise(CheckPluginState::CRITICAL);
             }
             $name = $db->fetchOne(
                 $db->select()->from('vm_snapshot', 'name')
@@ -76,9 +74,7 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
                 date('Y-m-d H:i', $info->ts_oldest)
             );
         }
-        return [
-            new SingleCheckResult($state, $output)
-        ];
+        return [new SingleCheckResult($state, $output)];
     }
 
     public function getParameters(): array
@@ -86,20 +82,20 @@ public function getParameters(): array
         return [
             'warning_if_more_than' => ['number', [
                 'label' => $this->translate('Raise Warning if more than X snapshots'),
-                'placeholder' => 'unset',
+                'placeholder' => 'unset'
             ]],
             'critical_if_more_than' => ['number', [
                 'label' => $this->translate('Raise Critical if more than X snapshots'),
-                'placeholder' => 'unset',
+                'placeholder' => 'unset'
             ]],
             'warning_if_older_than' => ['number', [
                 'label' => $this->translate('Raise Warning for snapshots older than X days'),
-                'placeholder' => 'unset',
+                'placeholder' => 'unset'
             ]],
             'critical_if_older_than' => ['number', [
                 'label' => $this->translate('Raise Critical for snapshots older than X days'),
-                'placeholder' => 'unset',
-            ]],
+                'placeholder' => 'unset'
+            ]]
         ];
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Definition/VMwareObjectStateRuleDefinition.php b/library/Vspheredb/Monitoring/Rule/Definition/VMwareObjectStateRuleDefinition.php
index 55b1256e..68406868 100644
--- a/library/Vspheredb/Monitoring/Rule/Definition/VMwareObjectStateRuleDefinition.php
+++ b/library/Vspheredb/Monitoring/Rule/Definition/VMwareObjectStateRuleDefinition.php
@@ -14,7 +14,7 @@ class VMwareObjectStateRuleDefinition extends MonitoringRuleDefinition
     public const SUPPORTED_OBJECT_TYPES = [
         ObjectType::HOST_SYSTEM,
         ObjectType::VIRTUAL_MACHINE,
-        ObjectType::DATASTORE,
+        ObjectType::DATASTORE
     ];
 
     public static function getIdentifier(): string
@@ -32,15 +32,13 @@ public function checkObject(BaseDbObject $object, Settings $settings): array
         try {
             $color = $object->object()->get('overall_status');
             $message = $this->getStatusMessageForColor($color);
-        } catch (NotFoundError $e) {
+        } catch (NotFoundError) {
             $color = 'gray';
             $message = 'Could not find the related Managed Object, please check my vCenter permissions';
         }
-        $state = MonitoringStateTrigger::getMonitoringState($settings->get("trigger_on_$color"));
+        $state = MonitoringStateTrigger::nullableFrom($settings->get("trigger_on_$color"))->monitoringState();
 
-        return [
-            new SingleCheckResult($state, $message)
-        ];
+        return [new SingleCheckResult($state, $message)];
     }
 
     protected function getStatusMessageForColor($color): string
@@ -56,9 +54,9 @@ protected function getStatusMessageForColor($color): string
     public function getInternalDefaults(): array
     {
         return [
-            'trigger_on_gray'   => MonitoringStateTrigger::RAISE_CRITICAL,
-            'trigger_on_yellow' => MonitoringStateTrigger::RAISE_WARNING,
-            'trigger_on_red'    => MonitoringStateTrigger::RAISE_CRITICAL
+            'trigger_on_gray'   => MonitoringStateTrigger::RAISE_CRITICAL->value,
+            'trigger_on_yellow' => MonitoringStateTrigger::RAISE_WARNING->value,
+            'trigger_on_red'    => MonitoringStateTrigger::RAISE_CRITICAL->value
         ];
     }
 
@@ -66,15 +64,15 @@ public function getParameters(): array
     {
         return [
             'trigger_on_yellow' => ['state_trigger', [
-                'label' => $this->translate('When VMware shows YELLOW'),
+                'label' => $this->translate('When VMware shows YELLOW')
             ]],
             'trigger_on_gray' => ['state_trigger', [
                 'label' => $this->translate('When VMware shows GRAY'),
                 'description' => $this->translate('VM might be unreachable')
             ]],
             'trigger_on_red' => ['state_trigger', [
-                'label' => $this->translate('When VMware shows RED'),
-            ]],
+                'label' => $this->translate('When VMware shows RED')
+            ]]
         ];
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Enum/CheckPluginState.php b/library/Vspheredb/Monitoring/Rule/Enum/CheckPluginState.php
new file mode 100644
index 00000000..133c5f62
--- /dev/null
+++ b/library/Vspheredb/Monitoring/Rule/Enum/CheckPluginState.php
@@ -0,0 +1,104 @@
+<?php
+
+namespace Icinga\Module\Vspheredb\Monitoring\Rule\Enum;
+
+use InvalidArgumentException;
+use RuntimeException;
+
+enum CheckPluginState: int
+{
+    case OK = 0;
+    case WARNING = 1;
+    case CRITICAL = 2;
+    case UNKNOWN = 3;
+
+    public function sortValue(): int
+    {
+        return match ($this) {
+            self::OK       => 0,
+            self::WARNING  => 1,
+            self::CRITICAL => 3,
+            self::UNKNOWN  => 2
+        };
+    }
+
+    public function color(): string
+    {
+        return match ($this) {
+            self::OK       => 'green',
+            self::WARNING  => 'brown',
+            self::CRITICAL => 'red',
+            self::UNKNOWN  => 'purple'
+        };
+    }
+
+    public static function fromTrigger(MonitoringStateTrigger $trigger): self
+    {
+        foreach (CheckPluginState::cases() as $case) {
+            if ($case->name === strtoupper($trigger->value)) {
+                return $case;
+            }
+        }
+
+        throw new InvalidArgumentException("$trigger->value is not a valid state name");
+    }
+
+    /**
+     * @param CheckPluginState $state
+     *
+     * @return self
+     */
+    public function raise(CheckPluginState $state): self
+    {
+        if ($state->sortValue() > self::sortValue()) {
+            return $state;
+        }
+
+        return $this;
+    }
+
+    public function isProblem(): bool
+    {
+        return $this !== CheckPluginState::OK;
+    }
+
+    public static function compare(CheckPluginState $left, CheckPluginState $right): int
+    {
+        return $left->sortValue() <=> $right->sortValue();
+    }
+
+    public static function getBest(CheckPluginState ...$states): CheckPluginState
+    {
+        $formerState = array_shift($states);
+        if ($formerState === null) {
+            throw new RuntimeException('Comparing an empty state list is not possible');
+        }
+        while ($state = array_shift($states)) {
+            if (self::compare($formerState, $state) === 1) {
+                $formerState = $state;
+            }
+        }
+
+        return $formerState;
+    }
+
+    public static function getWorst(CheckPluginState ...$states): CheckPluginState
+    {
+        $formerState = array_shift($states);
+        if ($formerState === null) {
+            throw new RuntimeException('Comparing an empty state list is not possible');
+        }
+        while ($state = array_shift($states)) {
+            if (self::compare($formerState, $state) === -1) {
+                $formerState = $state;
+            }
+        }
+
+        return $formerState;
+    }
+
+    public function getExitCode(): int
+    {
+        return $this->value;
+    }
+}
diff --git a/library/Vspheredb/Monitoring/Rule/Enum/MonitoringStateTrigger.php b/library/Vspheredb/Monitoring/Rule/Enum/MonitoringStateTrigger.php
index dc51d4f5..37f12468 100644
--- a/library/Vspheredb/Monitoring/Rule/Enum/MonitoringStateTrigger.php
+++ b/library/Vspheredb/Monitoring/Rule/Enum/MonitoringStateTrigger.php
@@ -2,24 +2,41 @@
 
 namespace Icinga\Module\Vspheredb\Monitoring\Rule\Enum;
 
-use Icinga\Module\Vspheredb\Monitoring\CheckPluginState;
-
-class MonitoringStateTrigger
+enum MonitoringStateTrigger: string
 {
-    public const IGNORE         = 'ignore';
-    public const RAISE_WARNING  = 'warning';
-    public const RAISE_CRITICAL = 'critical';
-    public const RAISE_UNKNOWN  = 'unknown';
+    case IGNORE = 'ignore';
+    case RAISE_WARNING  = 'warning';
+    case RAISE_CRITICAL = 'critical';
+    case RAISE_UNKNOWN  = 'unknown';
 
-    public static function getMonitoringState(?string $trigger): CheckPluginState
+    /**
+     * Allow to create a trigger out of null. Null leads to the IGNORE case.
+     *
+     * @param ?string $from
+     *
+     * @return self
+     */
+    public static function nullableFrom(?string $from): self
     {
-        switch ($trigger) {
-            case self::RAISE_WARNING:
-            case self::RAISE_CRITICAL:
-            case self::RAISE_UNKNOWN:
-                return new CheckPluginState($trigger);
+        if ($from === null) {
+            return self::IGNORE;
         }
 
-        return new CheckPluginState();
+        return self::from($from);
+    }
+
+    /**
+     * Get the monitoring state for the trigger
+     *
+     * @return CheckPluginState
+     */
+    public function monitoringState(): CheckPluginState
+    {
+        return match ($this) {
+            self::RAISE_WARNING  => CheckPluginState::fromTrigger(self::RAISE_WARNING),
+            self::RAISE_CRITICAL => CheckPluginState::fromTrigger(self::RAISE_CRITICAL),
+            self::RAISE_UNKNOWN  => CheckPluginState::fromTrigger(self::RAISE_UNKNOWN),
+            default              => CheckPluginState::OK
+        };
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Enum/ObjectType.php b/library/Vspheredb/Monitoring/Rule/Enum/ObjectType.php
index 655d47e7..5a2468e9 100644
--- a/library/Vspheredb/Monitoring/Rule/Enum/ObjectType.php
+++ b/library/Vspheredb/Monitoring/Rule/Enum/ObjectType.php
@@ -6,48 +6,100 @@
 use Icinga\Module\Vspheredb\DbObject\Datastore;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
+use InvalidArgumentException;
+use RuntimeException;
 
-class ObjectType
+enum ObjectType: string
 {
-    // No enum, not yet.
-    public const HOST_SYSTEM = 'host';
-    public const VIRTUAL_MACHINE = 'vm';
-    public const DATASTORE = 'datastore';
-
-    public const TYPES = [
-        self::HOST_SYSTEM,
-        self::VIRTUAL_MACHINE,
-        self::DATASTORE,
-    ];
-
-    public const TYPE_CLASSES = [
-        self::HOST_SYSTEM => HostSystem::class,
-        self::VIRTUAL_MACHINE => VirtualMachine::class,
-        self::DATASTORE => Datastore::class,
-    ];
-
-    public const DB_CLASS_TYPE = [
-        HostSystem::class     => self::HOST_SYSTEM,
-        VirtualMachine::class => self::VIRTUAL_MACHINE,
-        Datastore::class      => self::DATASTORE,
-    ];
-
-    public static function getDbObjectType(BaseDbObject $object): string
+    case HOST_SYSTEM = 'host';
+    case VIRTUAL_MACHINE = 'vm';
+    case DATASTORE = 'datastore';
+
+    /**
+     * Create an ObjectType from a database object
+     *
+     * @param BaseDbObject $object
+     *
+     * @return self
+     */
+    public static function fromDbObject(BaseDbObject $object): self
+    {
+        $dbClass = $object::class;
+
+        return match ($dbClass) {
+            HostSystem::class     => self::HOST_SYSTEM,
+            VirtualMachine::class => self::VIRTUAL_MACHINE,
+            Datastore::class      => self::DATASTORE,
+            default               => throw new RuntimeException("'$dbClass' is not supported (1)")
+        };
+    }
+
+    /**
+     * Create an ObjectType from a URL param
+     */
+    public static function fromParam(string $objectTypeParam): self
+    {
+        return match ($objectTypeParam) {
+            'HostSystem'     => self::HOST_SYSTEM,
+            'VirtualMachine' => self::VIRTUAL_MACHINE,
+            'Datastore'      => self::DATASTORE,
+            default          => throw new InvalidArgumentException('Unsupported object type: ' . $objectTypeParam)
+        };
+    }
+
+    /**
+     * Get the label for the object type
+     *
+     * @return string
+     */
+    public function label(): string
     {
-        return static::getDbClassType(get_class($object));
+        return match ($this) {
+            self::HOST_SYSTEM     => 'Host System',
+            self::VIRTUAL_MACHINE => 'Virtual Machine',
+            self::DATASTORE       => 'Datastore'
+        };
     }
 
     /**
-     * @param string $dbClass
+     * Get the URL for the object type
      *
      * @return string
      */
-    public static function getDbClassType(string $dbClass): string
+    public function url(): string
     {
-        if (isset(self::DB_CLASS_TYPE[$dbClass])) {
-            return self::DB_CLASS_TYPE[$dbClass];
-        }
+        return match ($this) {
+            self::HOST_SYSTEM     => 'vspheredb/host',
+            self::VIRTUAL_MACHINE => 'vspheredb/vm',
+            self::DATASTORE       => 'vspheredb/datastore',
+        };
+    }
 
-        throw new \RuntimeException("'$dbClass' is not supported (1)");
+    /**
+     * Get the class for the object type
+     *
+     * @return class-string
+     */
+    public function class(): string
+    {
+        return match ($this) {
+            self::HOST_SYSTEM     => HostSystem::class,
+            self::VIRTUAL_MACHINE => VirtualMachine::class,
+            self::DATASTORE       => Datastore::class,
+        };
+    }
+
+    /**
+     * Get the table for the object type
+     *
+     * @return string
+     */
+    public function table(): string
+    {
+        return match ($this) {
+            self::HOST_SYSTEM     => 'host_system',
+            self::VIRTUAL_MACHINE => 'virtual_machine',
+            self::DATASTORE       => 'datastore',
+        };
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Enum/ResultStatus.php b/library/Vspheredb/Monitoring/Rule/Enum/ResultStatus.php
new file mode 100644
index 00000000..7815abdb
--- /dev/null
+++ b/library/Vspheredb/Monitoring/Rule/Enum/ResultStatus.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Icinga\Module\Vspheredb\Monitoring\Rule\Enum;
+
+enum ResultStatus: string
+{
+    case CREATED = 'created';
+    case MODIFIED = 'modified';
+    case UNMODIFIED = 'unmodified';
+    case DELETED = 'deleted';
+}
diff --git a/library/Vspheredb/Monitoring/Rule/Form/Element/NumberElement.php b/library/Vspheredb/Monitoring/Rule/Form/Element/NumberElement.php
index d41ac8c3..3e08ae7d 100644
--- a/library/Vspheredb/Monitoring/Rule/Form/Element/NumberElement.php
+++ b/library/Vspheredb/Monitoring/Rule/Form/Element/NumberElement.php
@@ -6,15 +6,11 @@
 
 class NumberElement extends Number
 {
-    public function getValue()
+    public function getValue(): mixed
     {
         $value = parent::getValue();
         if (is_string($value)) {
-            if (ctype_digit($value)) {
-                return (int) $value;
-            } else {
-                return (float) $value;
-            }
+            return ctype_digit($value) ? (int) $value : (float) $value;
         }
 
         return $value;
diff --git a/library/Vspheredb/Monitoring/Rule/InheritedSettings.php b/library/Vspheredb/Monitoring/Rule/InheritedSettings.php
index cc6415f1..80df5e10 100644
--- a/library/Vspheredb/Monitoring/Rule/InheritedSettings.php
+++ b/library/Vspheredb/Monitoring/Rule/InheritedSettings.php
@@ -7,11 +7,11 @@
 
 class InheritedSettings extends Settings
 {
-    /** @var MonitoringRulesTree */
-    protected $tree;
+    protected MonitoringRulesTree $tree;
 
-    protected $inheritedFromUuids = [];
-    protected $inheritedFromNames = [];
+    protected array $inheritedFromUuids = [];
+
+    protected array $inheritedFromNames = [];
 
     public function __construct(MonitoringRulesTree $tree)
     {
@@ -38,7 +38,7 @@ public static function loadForUuids($uuids, MonitoringRulesTree $tree, Db $db):
         return $self;
     }
 
-    public function applyInherited(Settings $settings, $inheritedFrom = null)
+    public function applyInherited(Settings $settings, $inheritedFrom = null): void
     {
         foreach ($settings->settings as $key => $value) {
             $this->setInherited($key, $value, $inheritedFrom);
@@ -83,9 +83,10 @@ public function dump(): array
 
     /**
      * @param string $prefix
+     *
      * @return $this|InheritedSettings
      */
-    public function withRemovedPrefix(string $prefix)
+    public function withRemovedPrefix(string $prefix): InheritedSettings
     {
         $length = strlen($prefix);
         $settings = new InheritedSettings($this->tree);
@@ -111,7 +112,7 @@ public function listMainInheritedKeys(): array
         return array_keys($keys);
     }
 
-    public function setInternalDefaults(RuleSetRegistry $registry)
+    public function setInternalDefaults(RuleSetRegistry $registry): void
     {
         foreach ($registry->getSets() as $set) {
             foreach ($set->getRules() as $rule) {
@@ -131,12 +132,12 @@ public function setInternalDefaults(RuleSetRegistry $registry)
 
     /**
      * @param string $name
-     * @param $value
-     * @param $inheritedFrom
+     * @param mixed $value
+     * @param ?string $inheritedFrom
      *
      * @return void
      */
-    public function setInherited(string $name, $value, $inheritedFrom = null): void
+    public function setInherited(string $name, mixed $value, ?string $inheritedFrom = null): void
     {
         if ($this->get($name) !== null) {
             return;
diff --git a/library/Vspheredb/Monitoring/Rule/InstanceKeys.php b/library/Vspheredb/Monitoring/Rule/InstanceKeys.php
index baa48294..62d790e8 100644
--- a/library/Vspheredb/Monitoring/Rule/InstanceKeys.php
+++ b/library/Vspheredb/Monitoring/Rule/InstanceKeys.php
@@ -12,7 +12,8 @@ class InstanceKeys
     /**
      * @param array $values
      * @param RuleSet $set
-     * @param Rule|null $rule
+     * @param Rule $rule
+     *
      * @return UuidInterface[] List of UUIDs
      */
     public static function getListFrom(array $values, RuleSet $set, Rule $rule): array
diff --git a/library/Vspheredb/Monitoring/Rule/MonitoringRule.php b/library/Vspheredb/Monitoring/Rule/MonitoringRule.php
index f4795f6f..ff89c09a 100644
--- a/library/Vspheredb/Monitoring/Rule/MonitoringRule.php
+++ b/library/Vspheredb/Monitoring/Rule/MonitoringRule.php
@@ -7,10 +7,9 @@
 
 class MonitoringRule implements JsonSerialization
 {
-    protected $enabled = true;
+    protected bool $enabled = true;
 
-    /** @var MonitoringRuleSetDefinition */
-    protected $definition;
+    protected MonitoringRuleSetDefinition $definition;
 
     public function __construct(MonitoringRuleSetDefinition $definition)
     {
diff --git a/library/Vspheredb/Monitoring/Rule/MonitoringRuleSet.php b/library/Vspheredb/Monitoring/Rule/MonitoringRuleSet.php
index 9c96e534..d1d5a0b7 100644
--- a/library/Vspheredb/Monitoring/Rule/MonitoringRuleSet.php
+++ b/library/Vspheredb/Monitoring/Rule/MonitoringRuleSet.php
@@ -9,35 +9,27 @@
 class MonitoringRuleSet
 {
     public const TABLE = 'monitoring_rule_set';
+
     public const NO_OBJECT = '';
 
-    /** @var string */
-    protected $binaryUuid;
+    protected string $binaryUuid;
 
-    /** @var string */
-    protected $objectFolder;
+    protected string $objectFolder;
 
-    /** @var ?bool */
-    protected $enabled = null;
+    protected ?bool $enabled = null;
 
-    /** @var MonitoringRuleSetDefinition */
-    protected $definition;
+    protected ?MonitoringRuleSetDefinition $definition = null;
 
-    /** @var Settings */
-    protected $settings;
+    protected Settings $settings;
 
-    protected $fromDb = false;
+    protected bool $fromDb = false;
 
-    protected static $preloadCache = null;
+    protected static ?array $preloadCache = null;
 
     public function __construct(string $binaryUuid, string $objectFolder, ?Settings $settings = null)
     {
         $this->binaryUuid = $binaryUuid;
-        if ($settings === null) {
-            $this->settings = new Settings();
-        } else {
-            $this->settings = $settings;
-        }
+        $this->settings = $settings ?? new Settings();
         $this->objectFolder = $objectFolder;
     }
 
@@ -64,27 +56,28 @@ public static function loadOptionalForUuid(string $uuid, string $objectFolder, D
         return null;
     }
 
-    protected static function makeKey($objectUuid, $objectFolder): string
+    protected static function makeKey(?string $objectUuid, string $objectFolder): string
     {
         // correct would be using UUID, but bin2hex() is faster, and this is internal only
-        return ($objectUuid === null ? 'null' : bin2hex($objectUuid))
-            . '|'
-            . json_encode($objectFolder);
+        return ($objectUuid === null ? 'null' : bin2hex($objectUuid)) . '|' . json_encode($objectFolder);
     }
 
-    public static function preloadAll(Db $connection)
+    public static function preloadAll(Db $connection): void
     {
         $db = $connection->getDbAdapter();
         self::$preloadCache = [];
         foreach ($db->fetchAll($db->select()->from(MonitoringRuleSet::TABLE)) as $row) {
             $uuid = $row->object_uuid;
             $folder = $row->object_folder;
-            self::$preloadCache[self::makeKey($uuid, $folder)]
-                = new static($uuid, $folder, Settings::fromSerialization(JsonString::decode($row->settings)));
+            self::$preloadCache[self::makeKey($uuid, $folder)] = new static(
+                $uuid,
+                $folder,
+                Settings::fromSerialization(JsonString::decode($row->settings))
+            );
         }
     }
 
-    public static function clearPreloadCache()
+    public static function clearPreloadCache(): void
     {
         self::$preloadCache = null;
     }
@@ -109,7 +102,7 @@ public function store(Db $connection): bool
         $db->insert(MonitoringRuleSet::TABLE, [
             'object_uuid'   => $this->binaryUuid,
             'object_folder' => $this->objectFolder,
-            'settings'      => JsonString::encode($this->settings),
+            'settings'      => JsonString::encode($this->settings)
         ]);
         $this->fromDb = true;
 
@@ -121,10 +114,7 @@ public function delete(Db $connection): bool
         $existing = self::loadOptionalForUuid($this->binaryUuid, $this->objectFolder, $connection);
         $db = $connection->getDbAdapter();
         if ($existing) {
-            $rowCount = $db->delete(
-                MonitoringRuleSet::TABLE,
-                $this->createWhere($connection)
-            );
+            $rowCount = $db->delete(MonitoringRuleSet::TABLE, $this->createWhere($connection));
             $this->fromDb = false;
 
             return $rowCount > 0;
@@ -151,9 +141,9 @@ public function hasBeenLoadedFromDb(): bool
     }
 
     /**
-     * @return MonitoringRuleSetDefinition
+     * @return ?MonitoringRuleSetDefinition
      */
-    public function getDefinition(): MonitoringRuleSetDefinition
+    public function getDefinition(): ?MonitoringRuleSetDefinition
     {
         return $this->definition;
     }
@@ -168,6 +158,7 @@ public function getSettings(): Settings
 
     /**
      * @param Settings $settings
+     *
      * @return MonitoringRuleSet
      */
     public function setSettings(Settings $settings): MonitoringRuleSet
diff --git a/library/Vspheredb/Monitoring/Rule/MonitoringRulesTree.php b/library/Vspheredb/Monitoring/Rule/MonitoringRulesTree.php
index c3c66c0a..a321a511 100644
--- a/library/Vspheredb/Monitoring/Rule/MonitoringRulesTree.php
+++ b/library/Vspheredb/Monitoring/Rule/MonitoringRulesTree.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Monitoring\Rule;
 
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
 use ipl\I18n\Translation;
@@ -12,22 +13,17 @@ class MonitoringRulesTree
 
     public const ROOT_OBJECT_TYPE = 'root';
 
-    /** @var Db */
-    protected $db;
+    protected ?Db $db;
 
-    /** @var string */
-    protected $baseObjectFolderName;
+    protected string $baseObjectFolderName;
 
-    /** @var ?array */
-    protected $fetchedTree;
+    protected ?array $fetchedTree = null;
 
-    /** @var ?array */
-    protected $configList;
+    protected ?array $configList = null;
 
-    /** @var ?array */
-    protected $allNodes;
+    protected ?array $allNodes = null;
 
-    public function __construct(Db $db, $baseObjectFolderName)
+    public function __construct(Db $db, string $baseObjectFolderName)
     {
         $this->db = $db;
         $this->baseObjectFolderName = $baseObjectFolderName;
@@ -76,7 +72,7 @@ public function listParentUuidsFor(string $uuid): array
         return $parents;
     }
 
-    public function getRootNode()
+    public function getRootNode(): object
     {
         return (object) [
             'object_name' => $this->translate('All vCenters'),
@@ -101,7 +97,7 @@ public function hasConfigurationForUuid(string $uuid): bool
     }
 
     /**
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws NotFoundError
      */
     public function getInheritedSettingsFor(BaseDbObject $object): InheritedSettings
     {
@@ -161,11 +157,7 @@ protected function listAllConfiguredRuleSets(): array
 
     protected function getTree(): array
     {
-        if ($this->fetchedTree === null) {
-            $this->fetchedTree = $this->fetchTree();
-        }
-
-        return $this->fetchedTree;
+        return $this->fetchedTree ??= $this->fetchTree();
     }
 
     protected function fetchTree(): array
@@ -202,7 +194,7 @@ protected function fetchTree(): array
         return $root;
     }
 
-    public function discard()
+    public function discard(): void
     {
         $this->allNodes = null;
         $this->fetchedTree = null;
diff --git a/library/Vspheredb/Monitoring/Rule/MonitoringRulesTreeRenderer.php b/library/Vspheredb/Monitoring/Rule/MonitoringRulesTreeRenderer.php
index d15028bf..fb3d938f 100644
--- a/library/Vspheredb/Monitoring/Rule/MonitoringRulesTreeRenderer.php
+++ b/library/Vspheredb/Monitoring/Rule/MonitoringRulesTreeRenderer.php
@@ -17,25 +17,25 @@ class MonitoringRulesTreeRenderer extends BaseHtmlElement
 
     protected $defaultAttributes = [
         'class'            => 'tree',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    /** @var MonitoringRulesTree */
-    protected $tree;
-    protected $url;
+    protected MonitoringRulesTree $tree;
 
-    public function __construct(MonitoringRulesTree $tree, $url)
+    protected string $url;
+
+    public function __construct(MonitoringRulesTree $tree, string $url)
     {
         $this->tree = $tree;
         $this->url = $url;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->add($this->buildTree($this->tree->getRootNode()));
     }
 
-    protected function buildTree($node, $level = 0): HtmlElement
+    protected function buildTree(object $node, $level = 0): HtmlElement
     {
         $hasChildren = ! empty($node->children);
         $li = Html::tag('li');
@@ -63,14 +63,8 @@ protected function buildTree($node, $level = 0): HtmlElement
         return $li;
     }
 
-    protected function createLink($label, $uuid = null, $attributes = []): Link
+    protected function createLink(string $label, ?string $uuid = null, array $attributes = []): Link
     {
-        if ($uuid === null) {
-            $params = [];
-        } else {
-            $params = Util::uuidParams($uuid);
-        }
-
-        return Link::create($label, $this->url, $params, $attributes);
+        return Link::create($label, $this->url, $uuid === null ? [] : Util::uuidParams($uuid), $attributes);
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/RuleForm.php b/library/Vspheredb/Monitoring/Rule/RuleForm.php
index 3bdf44c2..6d8a5849 100644
--- a/library/Vspheredb/Monitoring/Rule/RuleForm.php
+++ b/library/Vspheredb/Monitoring/Rule/RuleForm.php
@@ -8,7 +8,10 @@
 use Icinga\Module\Vspheredb\Monitoring\Rule\Definition\MonitoringRuleSetDefinition as RuleSet;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Definition\RuleSetRegistry;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\MonitoringStateTrigger;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ResultStatus;
 use InvalidArgumentException;
+use ipl\Html\Attributes;
 use ipl\Html\FormElement\NumberElement;
 use ipl\Html\FormElement\SelectElement;
 use ipl\Html\FormElement\TextElement;
@@ -16,44 +19,36 @@
 use ipl\I18n\Translation;
 use Ramsey\Uuid\Uuid;
 use Ramsey\Uuid\UuidInterface;
+use RuntimeException;
 
 class RuleForm extends Form
 {
     use Translation;
 
     public const NEXT_UUID = '00000000-0000-0000-0000-000000000000';
-    public const RESULT_CREATED    = 'created';
-    public const RESULT_MODIFIED   = 'modified';
-    public const RESULT_UNMODIFIED = 'unmodified';
-    public const RESULT_DELETED    = 'deleted';
 
-    /** @var string */
-    protected $objectType;
+    protected ObjectType $objectType;
 
-    /** @var string */
-    protected $binaryUuid;
+    protected string $binaryUuid;
 
-    /** @var Db */
-    protected $db;
+    protected Db $db;
 
-    /** @var InheritedSettings */
-    protected $inherited;
+    protected InheritedSettings $inherited;
 
-    /** @var MonitoringRuleSet|null */
-    protected $loadedSet;
+    protected ?MonitoringRuleSet $loadedSet;
 
-    /** @var string Any of self::RESULT_* */
-    protected $result;
+    /** @var ?ResultStatus Any of self::RESULT_* */
+    protected ?ResultStatus $result = null;
 
     public function __construct(
-        string $objectType,
+        ObjectType $objectType,
         string $binaryUuid,
         Db $db,
         InheritedSettings $inherited,
         ?MonitoringRuleSet $loadedSet = null
     ) {
         $this->addPluginLoader('element', '\\Icinga\\Module\\Vspheredb\\Monitoring\\Rule\\Form\\Element', 'Element');
-        $this->addAttributes(['class' => 'ruleform']);
+        $this->addAttributes(Attributes::create(['class' => 'ruleform']));
         $this->objectType = $objectType;
         $this->db = $db;
         $this->binaryUuid = $binaryUuid;
@@ -64,7 +59,7 @@ public function __construct(
         }
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $sets = RuleSetRegistry::default()->getSets();
         foreach ($sets as $set) {
@@ -108,16 +103,15 @@ protected function assemble()
         $this->applyInheritedInfo();
     }
 
-    protected function addRule(RuleSet $set, Rule $rule, ?UuidInterface $instance = null)
+    protected function addRule(RuleSet $set, Rule $rule, ?UuidInterface $instance = null): void
     {
         if ($instance === null) {
             $this->add(Html::tag('h3', $rule->getLabel()));
         } else {
-            if ($instance->toString() === self::NEXT_UUID) {
-                $this->add(Html::tag('h3', $rule->getLabel() . sprintf(' (%s)', $this->translate('new instance'))));
-            } else {
-                $this->add(Html::tag('h3', $rule->getLabel() . sprintf(' (%s)', $instance->toString())));
-            }
+            $uuid = $instance->toString() === self::NEXT_UUID
+                ? $this->translate('new instance')
+                : $instance->toString();
+            $this->add(Html::tag('h3', $rule->getLabel() . sprintf(' (%s)', $uuid)));
         }
         $prefix = Settings::prefix($set, $rule, $instance);
         $this->addEnabledSetting($prefix);
@@ -128,7 +122,7 @@ protected function addRule(RuleSet $set, Rule $rule, ?UuidInterface $instance =
         }
     }
 
-    protected function createRuleElement($elementName, $definition)
+    protected function createRuleElement($elementName, $definition): void
     {
         $elementType = array_shift($definition);
         $options = array_shift($definition) ?: [];
@@ -140,14 +134,14 @@ protected function createRuleElement($elementName, $definition)
         }
     }
 
-    protected function applyInheritedInfo()
+    protected function applyInheritedInfo(): void
     {
         foreach ((array) $this->inherited->jsonSerialize() as $key => $value) {
             $this->setInheritedValue($key, $value, $this->inherited->getInheritedFromName($key));
         }
     }
 
-    protected function setInheritedValue($elementName, $value, $sourceName = null)
+    protected function setInheritedValue(string $elementName, mixed $value, ?string $sourceName = null): void
     {
         if ($this->getValue($elementName) !== null) {
             return;
@@ -178,7 +172,7 @@ protected function setInheritedValue($elementName, $value, $sourceName = null)
         }
     }
 
-    protected function assertValidateParameterName($name)
+    protected function assertValidateParameterName($name): void
     {
         if (! preg_match('/^[A-z]+[A-z0-9_]*$/', $name)) {
             throw new InvalidArgumentException("'$name' is not a valid parameter name");
@@ -230,8 +224,13 @@ public function getNormalizedValues(): array
         return $result;
     }
 
-    protected function applyResultValue(&$values, $prefix, $key, $elementType, $storingPrefix = null)
-    {
+    protected function applyResultValue(
+        array &$values,
+        string $prefix,
+        string $key,
+        string $elementType,
+        ?string $storingPrefix = null
+    ): void {
         $storingKey = ($storingPrefix ?? $prefix) . $key;
         $key = $prefix . $key;
         $value = $this->getValue($key);
@@ -243,67 +242,61 @@ protected function applyResultValue(&$values, $prefix, $key, $elementType, $stor
         }
     }
 
-    protected function normalizeBoolean($value): ?bool
+    protected function normalizeBoolean(?string $value): ?bool
     {
-        switch ($value) {
-            case null:
-                return null;
-            case 'y':
-                return true;
-            case 'n':
-                return false;
-        }
-
-        throw new \RuntimeException("'$value' is not a valid boolean value");
+        return match ($value) {
+            null    => null,
+            'y'     => true,
+            'n'     => false,
+            default => throw new RuntimeException("'$value' is not a valid boolean value")
+        };
     }
 
-    protected function addEnabledSetting($prefix)
+    protected function addEnabledSetting(string $prefix): void
     {
         $elementName = $prefix . Settings::KEY_ENABLED;
         $this->addElement('boolean', $elementName, [
             'label'   => $this->translate('Enabled'),
-            // 'class' => 'autosubmit',
+            // 'class' => 'autosubmit'
         ]);
         $this->setInheritedValue($elementName, true);
     }
 
-    protected function addStateTriggerElement(string $name, $options = [])
+    protected function addStateTriggerElement(string $name, array $options = []): void
     {
         $selectOptions = [
             '' => $this->translate('Not configured / Inherited'),
-            MonitoringStateTrigger::IGNORE => $this->translate('Do nothing'),
-            MonitoringStateTrigger::RAISE_WARNING => $this->translate('Trigger a Warning state'),
-            MonitoringStateTrigger::RAISE_CRITICAL => $this->translate('Trigger a Critical state'),
-            MonitoringStateTrigger::RAISE_UNKNOWN => $this->translate('Trigger an Unknown state'),
+            MonitoringStateTrigger::IGNORE->value => $this->translate('Do nothing'),
+            MonitoringStateTrigger::RAISE_WARNING->value => $this->translate('Trigger a Warning state'),
+            MonitoringStateTrigger::RAISE_CRITICAL->value => $this->translate('Trigger a Critical state'),
+            MonitoringStateTrigger::RAISE_UNKNOWN->value => $this->translate('Trigger an Unknown state')
         ];
 
-        $this->addElement('select', $name, [
-            'options' => $selectOptions,
-        ] + $options);
+        $this->addElement('select', $name, ['options' => $selectOptions] + $options);
     }
 
     public function hasBeenCreated(): bool
     {
-        return $this->result === self::RESULT_CREATED;
+        return $this->result === ResultStatus::CREATED;
     }
 
     public function hasBeenModified(): bool
     {
-        return $this->result === self::RESULT_MODIFIED;
+        return $this->result === ResultStatus::MODIFIED;
     }
 
     public function hasNotBeenModified(): bool
     {
-        return $this->result === self::RESULT_UNMODIFIED;
+        return $this->result === ResultStatus::UNMODIFIED;
     }
 
     public function hasBeenDeleted(): bool
     {
-        return $this->result === self::RESULT_DELETED;
+        return $this->result === ResultStatus::DELETED;
     }
 
 
-    protected function onSuccess()
+    protected function onSuccess(): void
     {
         $values = $this->getNormalizedValues();
         $settings = new Settings($values);
@@ -311,23 +304,17 @@ protected function onSuccess()
             $set = $this->loadedSet;
             $set->setSettings($settings);
         } else {
-            $set = new MonitoringRuleSet($this->binaryUuid, $this->objectType, $settings);
+            $set = new MonitoringRuleSet($this->binaryUuid, $this->objectType->value, $settings);
         }
         if (empty($values)) {
-            if ($set->delete($this->db)) {
-                $result = self::RESULT_DELETED;
-            } else {
-                $result = self::RESULT_UNMODIFIED; // No different message for now
-            }
+            $this->result = $set->delete($this->db) ? ResultStatus::DELETED : ResultStatus::UNMODIFIED;
         } else {
             if ($set->hasBeenLoadedFromDb()) {
-                $result = $set->store($this->db) ? self::RESULT_MODIFIED : self::RESULT_UNMODIFIED;
+                $this->result = $set->store($this->db) ? ResultStatus::MODIFIED : ResultStatus::UNMODIFIED;
             } else {
                 $set->store($this->db);
-                $result = self::RESULT_CREATED;
+                $this->result = ResultStatus::CREATED;
             }
         }
-
-        $this->result = $result;
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/RuleSetLoader.php b/library/Vspheredb/Monitoring/Rule/RuleSetLoader.php
index 1d5170a2..8c01abb6 100644
--- a/library/Vspheredb/Monitoring/Rule/RuleSetLoader.php
+++ b/library/Vspheredb/Monitoring/Rule/RuleSetLoader.php
@@ -6,11 +6,9 @@
 
 class RuleSetLoader
 {
-    /** @var MonitoringRulesTree */
-    protected $tree;
+    protected MonitoringRulesTree $tree;
 
-    /** @var Db */
-    protected $db;
+    protected Db $db;
 
     public function __construct(MonitoringRulesTree $tree, Db $db)
     {
diff --git a/library/Vspheredb/Monitoring/Rule/RulesTable.php b/library/Vspheredb/Monitoring/Rule/RulesTable.php
index 6ec981fa..81b605a8 100644
--- a/library/Vspheredb/Monitoring/Rule/RulesTable.php
+++ b/library/Vspheredb/Monitoring/Rule/RulesTable.php
@@ -7,7 +7,7 @@
 class RulesTable extends Table
 {
     /** @var MonitoringRuleSet[] */
-    protected $ruleSets;
+    protected array $ruleSets;
 
     /**
      * @param MonitoringRuleSet[] $ruleSets
@@ -17,12 +17,10 @@ public function __construct(array $ruleSets)
         $this->ruleSets = $ruleSets;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         foreach ($this->ruleSets as $set) {
-            $this->add(Table::row([
-                $set->getDefinition()::getIdentifier()
-            ]));
+            $this->add(Table::row([$set->getDefinition()::getIdentifier()]));
         }
     }
 }
diff --git a/library/Vspheredb/Monitoring/Rule/Settings.php b/library/Vspheredb/Monitoring/Rule/Settings.php
index 7b00dcb0..4de89a1e 100644
--- a/library/Vspheredb/Monitoring/Rule/Settings.php
+++ b/library/Vspheredb/Monitoring/Rule/Settings.php
@@ -11,6 +11,7 @@
 class Settings extends SettingsDataType
 {
     public const KEY_SEPARATOR = '/';
+
     public const KEY_ENABLED = '_enabled';
 
     public function isDisabled(?RuleSet $set = null, ?Rule $rule = null): bool
@@ -38,18 +39,20 @@ public function listMainKeys(): array
 
     /**
      * @param string $key
+     *
      * @return $this|Settings
      */
-    public function withRemovedKey(string $key)
+    public function withRemovedKey(string $key): Settings
     {
         return $this->withRemovedPrefix($key . Settings::KEY_SEPARATOR);
     }
 
     /**
      * @param string $prefix
+     *
      * @return $this|Settings
      */
-    public function withRemovedPrefix(string $prefix)
+    public function withRemovedPrefix(string $prefix): Settings
     {
         $length = strlen($prefix);
         $settings = new Settings();
@@ -74,10 +77,9 @@ public static function prefix(?RuleSet $set = null, ?Rule $rule = null, ?UuidInt
         }
         $prefix = $set::getIdentifier() . self::KEY_SEPARATOR;
         if ($rule) {
-            if ($instance === null) {
-                $prefix .= $rule::getIdentifier() . self::KEY_SEPARATOR;
-            } else {
-                $prefix .= $rule::getIdentifier() . self::KEY_SEPARATOR . $instance->toString() . self::KEY_SEPARATOR;
+            $prefix .= $rule::getIdentifier() . self::KEY_SEPARATOR;
+            if ($instance !== null) {
+                $prefix .= $instance->toString() . self::KEY_SEPARATOR;
             }
         } elseif ($instance) {
             throw new InvalidArgumentException('Rule instance requires a rule');
diff --git a/library/Vspheredb/Monitoring/SingleCheckResult.php b/library/Vspheredb/Monitoring/SingleCheckResult.php
index 86b52698..f493cfce 100644
--- a/library/Vspheredb/Monitoring/SingleCheckResult.php
+++ b/library/Vspheredb/Monitoring/SingleCheckResult.php
@@ -2,13 +2,13 @@
 
 namespace Icinga\Module\Vspheredb\Monitoring;
 
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\CheckPluginState;
+
 class SingleCheckResult implements CheckResultInterface
 {
-    /** @var CheckPluginState */
-    protected $state;
+    protected CheckPluginState $state;
 
-    /** @var string */
-    protected $output;
+    protected string $output;
 
     public function __construct(CheckPluginState $state, string $output)
     {
diff --git a/library/Vspheredb/PathLookup.php b/library/Vspheredb/PathLookup.php
index ebee4277..af489a36 100644
--- a/library/Vspheredb/PathLookup.php
+++ b/library/Vspheredb/PathLookup.php
@@ -6,25 +6,26 @@
 use gipfl\ZfDb\Adapter\Adapter;
 use Icinga\Module\Vspheredb\Db\DbUtil;
 use Ramsey\Uuid\Uuid;
+use Zend_Db_Adapter_Abstract;
 
 class PathLookup
 {
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected Zend_Db_Adapter_Abstract|Adapter $db;
 
     /**
-     * @param Adapter|\Zend_Db_Adapter_Abstract $db
+     * @param Zend_Db_Adapter_Abstract|Adapter $db
      */
-    public function __construct($db)
+    public function __construct(Zend_Db_Adapter_Abstract|Adapter $db)
     {
         $this->db = $db;
     }
 
     /**
-     * @param $uuid
+     * @param string $uuid
+     *
      * @return string|Link
      */
-    public function linkToObject($uuid)
+    public function linkToObject(string $uuid): Link|string
     {
         if (empty($uuid)) {
             return '-';
@@ -34,39 +35,31 @@ public function linkToObject($uuid)
             ->from(['o' => 'object'], ['object_name', 'object_type'])
             ->where('uuid = ?', DbUtil::quoteBinaryCompat($uuid, $this->db));
 
-        $row = $this->db->fetchRow($query);
-        if ($row) {
+        if ($row = $this->db->fetchRow($query)) {
             return Link::create(
                 $row->object_name,
                 $this->getBaseUrlByType($row->object_type),
                 ['uuid' => Uuid::fromBytes($uuid)->toString()],
                 ['data-base-target' => '_next']
             );
-        } else {
-            return '-';
         }
+
+        return '-';
     }
 
-    protected function getBaseUrlByType($type): string
+    protected function getBaseUrlByType(string $type): string
     {
-        switch ($type) {
-            case 'Datastore':
-                return 'vspheredb/datastore';
-            case 'HostSystem':
-                return 'vspheredb/host';
-            case 'VirtualMachine':
-                return 'vspheredb/vm';
-            case 'ClusterComputeResource':
-            case 'ComputeResource':
-                return 'vspheredb/hosts';
-            case 'Datacenter':
-            case 'Folder':
-            default:
-                return 'vspheredb/vms';
-        }
+        return match ($type) {
+            'Datastore'       => 'vspheredb/datastore',
+            'HostSystem'      => 'vspheredb/host',
+            'VirtualMachine'  => 'vspheredb/vm',
+            'ClusterComputeResource',
+            'ComputeResource' => 'vspheredb/hosts',
+            default           => 'vspheredb/vms'
+        };
     }
 
-    public function getObjectName($uuid): string
+    public function getObjectName(string $uuid): string
     {
         $query = $this->db->select()
             ->from(['o' => 'object'], 'object_name')
@@ -75,7 +68,7 @@ public function getObjectName($uuid): string
         return $this->db->fetchOne($query);
     }
 
-    public function getObjectNames($uuids): array
+    public function getObjectNames(array $uuids): array
     {
         if (empty($uuids)) {
             return [];
@@ -89,12 +82,12 @@ public function getObjectNames($uuids): array
         return $this->db->fetchPairs($query);
     }
 
-    public function listFoldersBelongingTo($uuid): array
+    public function listFoldersBelongingTo(string $uuid): array
     {
         return array_merge($this->listChildFoldersFor($uuid), [$uuid]);
     }
 
-    public function listChildFoldersFor($uuid): array
+    public function listChildFoldersFor(string $uuid): array
     {
         $folders = [];
         $puuid = $uuid;
@@ -108,22 +101,19 @@ public function listChildFoldersFor($uuid): array
         return $folders;
     }
 
-    protected function fetchChildFolderListFor($uuid): array
+    protected function fetchChildFolderListFor(string $uuid): array
     {
-        $query = $this->db->select()->from('object', 'uuid')
+        $query = $this->db->select()
+            ->from('object', 'uuid')
             ->where('parent_uuid = ?', DbUtil::quoteBinaryCompat($uuid, $this->db))
             ->where('object_type NOT IN (?)', ['HostSystem', 'VirtualMachine']);
 
         return $this->db->fetchCol($query);
     }
 
-    public function listPathTo($uuid, $includeSelf = true): array
+    public function listPathTo(string $uuid, bool $includeSelf = true): array
     {
-        if ($includeSelf) {
-            $parents = [$uuid];
-        } else {
-            $parents = [];
-        }
+        $parents = $includeSelf ? [$uuid] : [];
 
         $puuid = $uuid;
         while ($puuid = $this->fetchParentForId($puuid)) {
@@ -139,11 +129,6 @@ public function fetchParentForId($uuid): ?string
             ->from('object', 'parent_uuid')
             ->where('uuid = ?', DbUtil::quoteBinaryCompat($uuid, $this->db));
 
-        $parent = $this->db->fetchOne($query);
-        if ($parent) {
-            return $parent;
-        } else {
-            return null;
-        }
+        return $this->db->fetchOne($query) ?: null;
     }
 }
diff --git a/library/Vspheredb/PerformanceData/IcingaRrd/RrdImg.php b/library/Vspheredb/PerformanceData/IcingaRrd/RrdImg.php
index a72a52e4..86d37b7d 100644
--- a/library/Vspheredb/PerformanceData/IcingaRrd/RrdImg.php
+++ b/library/Vspheredb/PerformanceData/IcingaRrd/RrdImg.php
@@ -3,7 +3,9 @@
 namespace Icinga\Module\Vspheredb\PerformanceData\IcingaRrd;
 
 use gipfl\IcingaWeb2\Img;
+use ipl\Html\FormattedString;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 
 class RrdImg
 {
@@ -19,7 +21,7 @@ class RrdImg
 
     protected const COLOR_YELLOW = 'yellow'; // #FFED58
 
-    public static function vmIfTraffic($moref, $device)
+    public static function vmIfTraffic(string $moref, int $device): HtmlElement
     {
         return static::wrapImage(Html::sprintf(
             mt('vspheredb', 'Throughput (bits/s, %s RX / %s TX)'),
@@ -28,7 +30,7 @@ public static function vmIfTraffic($moref, $device)
         ), $moref, "iface$device", 'vSphereDB-vmIfTraffic');
     }
 
-    public static function vmIfPackets($moref, $device)
+    public static function vmIfPackets(string $moref, int $device): HtmlElement
     {
         return static::wrapImage(Html::sprintf(
             mt('vspheredb', 'Packets (%s / %s Unicast, %s BCast, %s MCast, %s Dropped)'),
@@ -40,7 +42,7 @@ public static function vmIfPackets($moref, $device)
         ), $moref, "iface$device", 'vSphereDB-vmIfPackets');
     }
 
-    public static function vmDiskSeeks($moref, $device)
+    public static function vmDiskSeeks(string $moref, string $device): HtmlElement
     {
         return static::wrapImage(Html::sprintf(
             mt('vspheredb', 'Disk Seeks: %s small / %s medium / %s large'),
@@ -50,7 +52,7 @@ public static function vmDiskSeeks($moref, $device)
         ), $moref, "disk$device", 'vSphereDB-vmDiskSeeks');
     }
 
-    public static function vmDiskReadWrites($moref, $device)
+    public static function vmDiskReadWrites(string $moref, string $device): HtmlElement
     {
         return static::wrapImage(Html::sprintf(
             mt('vspheredb', 'Average Number %s Reads / %s Writes'),
@@ -59,7 +61,7 @@ public static function vmDiskReadWrites($moref, $device)
         ), $moref, "disk$device", 'vSphereDB-vmDiskReadWrites');
     }
 
-    public static function vmDiskTotalLatency($moref, $device)
+    public static function vmDiskTotalLatency(string $moref, string $device): HtmlElement
     {
         return static::wrapImage(Html::sprintf(
             mt('vspheredb', 'Latency %s Read / %s Write'),
@@ -68,38 +70,41 @@ public static function vmDiskTotalLatency($moref, $device)
         ), $moref, "disk$device", 'vSphereDB-vmDiskTotalLatency');
     }
 
-    protected static function prepareImg($moref, $device, $template)
+    protected static function prepareImg(string $moref, string $device, string $template): Img
     {
         // Disk was 300x140, Net 340x180
         $width = 340;
         $height = 180;
-        $end = \floor(\time() / 300) * 300;
-        $start = $end - 86400;
+        $end = floor(time() / 300) * 300;
         $start = $end - 14400;
         $params = [
-            'file'     => \sprintf('%s/%s.rrd', $moref, $device),
+            'file'     => sprintf('%s/%s.rrd', $moref, $device),
             'height'   => $height,
             'width'    => $width,
             'rnd'      => floor(time() / 20),
             'format'   => 'png',
             'start'    => $start,
-            'end'      => $end,
+            'end'      => $end
         ];
 
         return Img::create('rrd/img', $params + ['template' => $template], ['class' => 'rrd-image']);
     }
 
-    protected static function colorLegend($color)
+    protected static function colorLegend(string $color): HtmlElement
     {
         return Html::tag('div', ['class' => 'color-square color-' . $color]);
     }
 
-    protected static function wrapImage($title, $moref, $device, $template)
-    {
+    protected static function wrapImage(
+        FormattedString $title,
+        string $moref,
+        string $device,
+        string $template
+    ): HtmlElement {
         // TODO, CSS. disk was 1em, net 2em
         return Html::tag('div', ['class' => 'rrd-image-legend'], [
             Html::tag('strong', $title),
-            static::prepareImg($moref, $device, $template),
+            static::prepareImg($moref, $device, $template)
         ]);
     }
 }
diff --git a/library/Vspheredb/PerformanceData/InfluxConnectionForVcenterLoader.php b/library/Vspheredb/PerformanceData/InfluxConnectionForVcenterLoader.php
index de73e3b5..8ba4dd59 100644
--- a/library/Vspheredb/PerformanceData/InfluxConnectionForVcenterLoader.php
+++ b/library/Vspheredb/PerformanceData/InfluxConnectionForVcenterLoader.php
@@ -41,33 +41,28 @@ public static function load(VCenter $vCenter, CurlAsync $curl, LoopInterface $lo
             PerfdataConsumer::create((array) $row),
             $loop
         );
-        switch ($instance->getSetting('api_version')) {
-            case 'v1':
-                $influxDb = resolve(new InfluxDbConnectionV1(
-                    $curl,
-                    $instance->getSetting('base_url'),
-                    $instance->getSetting('username'),
-                    $instance->getSetting('password')
-                ));
-                break;
-            case 'v2':
-                $influxDb = resolve(new InfluxDbConnectionV2(
-                    $curl,
-                    $instance->getSetting('base_url'),
-                    $instance->getSetting('username'),
-                    $instance->getSetting('password')
-                    // $instance->getSetting('organization'),
-                    // $instance->getSetting('token')
-                ));
-                break;
-            default:
-                $influxDb = InfluxDbConnectionFactory::create(
-                    $curl,
-                    $instance->getSetting('base_url'),
-                    $instance->getSetting('username'),
-                    $instance->getSetting('password')
-                );
-        }
+        $influxDb = match ($instance->getSetting('api_version')) {
+            'v1'    => resolve(new InfluxDbConnectionV1(
+                $curl,
+                $instance->getSetting('base_url'),
+                $instance->getSetting('username'),
+                $instance->getSetting('password')
+            )),
+            'v2'    => resolve(new InfluxDbConnectionV2(
+                $curl,
+                $instance->getSetting('base_url'),
+                $instance->getSetting('username'),
+                $instance->getSetting('password')
+                // $instance->getSetting('organization'),
+                // $instance->getSetting('token')
+            )),
+            default => InfluxDbConnectionFactory::create(
+                $curl,
+                $instance->getSetting('base_url'),
+                $instance->getSetting('username'),
+                $instance->getSetting('password')
+            ),
+        };
 
         return $influxDb->then(function (InfluxDbConnection $influxDb) use ($vCenterSettings, $loop) {
             $influxDbWriter = new ChunkedInfluxDbWriter(
diff --git a/library/Vspheredb/PerformanceData/MetricCSVToInfluxDataPoint.php b/library/Vspheredb/PerformanceData/MetricCSVToInfluxDataPoint.php
index 0832f2a7..167e7b3d 100644
--- a/library/Vspheredb/PerformanceData/MetricCSVToInfluxDataPoint.php
+++ b/library/Vspheredb/PerformanceData/MetricCSVToInfluxDataPoint.php
@@ -29,31 +29,21 @@ public static function map(
         foreach ($metric->value as $series) {
             $key = static::makeKey($object, $series->id);
             $metric = $countersMap[$series->id->counterId];
-            foreach (
-                array_combine(
-                    $dates,
-                    explode(',', $series->value)
-                ) as $time => $value
-            ) {
+            foreach (array_combine($dates, explode(',', $series->value)) as $time => $value) {
                 $result[$time][$key][$metric] = $value === '' ? null : (int) $value;
             }
         }
         foreach ($result as $time => $results) {
             foreach ($results as $key => $metrics) {
                 if (! isset($tags[$key])) {
-                    if (count($tags) > 10) {
-                        $tagList = implode(', ', array_slice(array_keys($tags), 0, 10)) . ', ...';
-                    } else {
-                        $tagList = implode(', ', array_keys($tags));
-                    }
+                    $tagList = count($tags) > 10
+                        ? implode(', ', array_slice(array_keys($tags), 0, 10)) . ', ...'
+                        : implode(', ', array_keys($tags));
+
                     throw new InvalidArgumentException("Cannot find tags for '$key', got: $tagList");
                 }
-                yield new DataPoint(
-                    $measurementName,
-                    ['instance' => $key] + $tags[$key],
-                    $metrics,
-                    $time
-                );
+
+                yield new DataPoint($measurementName, ['instance' => $key] + $tags[$key], $metrics, $time);
             }
         }
     }
diff --git a/library/Vspheredb/Polling/ApiConnection.php b/library/Vspheredb/Polling/ApiConnection.php
index d910a934..e0570166 100644
--- a/library/Vspheredb/Polling/ApiConnection.php
+++ b/library/Vspheredb/Polling/ApiConnection.php
@@ -20,48 +20,47 @@ class ApiConnection implements EventEmitterInterface
     use EventEmitterTrait;
     use StateMachine;
 
+    // Events
     public const ON_READY = 'ready';
+
     public const ON_ERROR = 'error';
 
+    // States
     public const STATE_STOPPED = 'stopped';
+
     public const STATE_STOPPING = 'stopping';
+
     public const STATE_INIT = 'initializing';
+
     public const STATE_LOGIN = 'login';
+
     public const STATE_CONNECTED = 'connected';
+
     public const STATE_FAILING = 'failing';
 
-    /** @var CurlAsync */
-    protected $curl;
+    protected CurlAsync $curl;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected ?LoopInterface $loop = null;
 
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    protected $scheduledPollerStartup;
+    protected ?TimerInterface $scheduledPollerStartup = null;
 
-    /** @var ServerInfo */
-    protected $serverInfo;
+    protected ServerInfo $serverInfo;
 
-    protected $wsdlFile;
+    protected ?string $wsdlFile = null;
 
-    /** @var VsphereApi */
-    protected $api;
+    protected ?VsphereApi $api = null;
 
-    protected $stopping;
+    protected ?bool $stopping = null;
 
-    /** @var PromiseInterface */
-    protected $loginPromise;
+    protected ?PromiseInterface $loginPromise = null;
 
-    /** @var PromiseInterface */
-    protected $wsdlPromise;
+    protected ?PromiseInterface $wsdlPromise = null;
 
-    /** @var TimerInterface */
-    protected $sessionChecker;
+    protected ?TimerInterface $sessionChecker = null;
 
-    /** @var ?string */
-    protected $lastErrorMessage = null;
+    protected ?string $lastErrorMessage = null;
 
     public function __construct(CurlAsync $curl, ServerInfo $serverInfo, LoggerInterface $logger)
     {
@@ -88,18 +87,14 @@ public function __construct(CurlAsync $curl, ServerInfo $serverInfo, LoggerInter
         });
         $this->onTransition(self::STATE_INIT, self::STATE_STOPPING, function () {
             $this->stopping = true;
-            if ($this->wsdlPromise) {
-                $this->wsdlPromise->cancel();
-                $this->wsdlPromise = null;
-            }
+            $this->wsdlPromise?->cancel();
+            $this->wsdlPromise = null;
             $this->setState(self::STATE_STOPPED);
         });
         $this->onTransition(self::STATE_LOGIN, self::STATE_STOPPING, function () {
             $this->stopping = true;
-            if ($this->loginPromise) {
-                $this->loginPromise->cancel();
-                $this->loginPromise = null;
-            }
+            $this->loginPromise?->cancel();
+            $this->loginPromise = null;
             $this->setState(self::STATE_STOPPED);
         });
         // TODO: do we need failing -> stopping?
@@ -130,13 +125,13 @@ public function __construct(CurlAsync $curl, ServerInfo $serverInfo, LoggerInter
         });
     }
 
-    protected function stopSessionChecker()
+    protected function stopSessionChecker(): void
     {
         $this->loop->cancelTimer($this->sessionChecker);
         $this->sessionChecker = null;
     }
 
-    protected function runSessionChecker()
+    protected function runSessionChecker(): void
     {
         $this->sessionChecker = $this->loop->addPeriodicTimer(150, function () {
             $this->getApi()->eventuallyLogin()->then(null, function (Exception $e) {
@@ -148,22 +143,22 @@ protected function runSessionChecker()
         });
     }
 
-    public function getApi()
+    public function getApi(): ?VsphereApi
     {
         return $this->api;
     }
 
-    public function isReady()
+    public function isReady(): bool
     {
         return $this->getState() === self::STATE_CONNECTED;
     }
 
-    public function getServerInfo()
+    public function getServerInfo(): ServerInfo
     {
         return $this->serverInfo;
     }
 
-    protected function scheduleNextAttempt($delay = 60)
+    protected function scheduleNextAttempt($delay = 60): void
     {
         if ($this->scheduledPollerStartup) {
             return;
@@ -174,7 +169,7 @@ protected function scheduleNextAttempt($delay = 60)
         });
     }
 
-    protected function eventuallyRemoveScheduledAttempt()
+    protected function eventuallyRemoveScheduledAttempt(): void
     {
         if ($this->scheduledPollerStartup) {
             $this->loop->cancelTimer($this->scheduledPollerStartup);
@@ -182,7 +177,7 @@ protected function eventuallyRemoveScheduledAttempt()
         }
     }
 
-    protected function startWsdlDownload()
+    protected function startWsdlDownload(): void
     {
         $this->wsdlPromise = $this->fetchWsdl()
             ->then(function ($wsdlFile) {
@@ -199,13 +194,13 @@ protected function startWsdlDownload()
             });
     }
 
-    protected function eventuallyLogout()
+    protected function eventuallyLogout(): PromiseInterface
     {
         $api = new VsphereApi($this->wsdlFile, $this->serverInfo, $this->curl, $this->loop, $this->logger);
         return $api->eventuallyLogout();
     }
 
-    protected function login()
+    protected function login(): PromiseInterface
     {
         $api = new VsphereApi($this->wsdlFile, $this->serverInfo, $this->curl, $this->loop, $this->logger);
         return $this->loginPromise = $api->eventuallyLogin()->then(function (UserSession $session) use ($api) {
@@ -223,22 +218,23 @@ protected function login()
         });
     }
 
-    public function stop()
+    public function stop(): void
     {
         $this->setState(self::STATE_STOPPING);
     }
 
-    public function run(LoopInterface $loop)
+    public function run(LoopInterface $loop): void
     {
         $this->loop = $loop;
         $this->setState(self::STATE_INIT);
     }
 
-    public function fetchWsdl()
+    public function fetchWsdl(): PromiseInterface
     {
         $serverId = $this->serverInfo->getServerId();
         $cacheDir = SafeCacheDir::getSubDirectory("wsdl-$serverId");
         $loader = new WsdlLoader($cacheDir, $this->logger, $this->serverInfo, $this->curl);
+
         return $loader->fetchInitialWsdlFile($this->loop);
     }
 
@@ -247,7 +243,7 @@ public function getLastErrorMessage(): ?string
         return $this->lastErrorMessage;
     }
 
-    protected function logError($message)
+    protected function logError($message): void
     {
         $this->lastErrorMessage = $message;
         $this->logger->error($message);
diff --git a/library/Vspheredb/Polling/ApiConnectionHandler.php b/library/Vspheredb/Polling/ApiConnectionHandler.php
index 675fb867..102794ab 100644
--- a/library/Vspheredb/Polling/ApiConnectionHandler.php
+++ b/library/Vspheredb/Polling/ApiConnectionHandler.php
@@ -21,42 +21,39 @@ class ApiConnectionHandler implements EventEmitterInterface
     use EventEmitterTrait;
 
     public const ON_INITIALIZED_SERVER = 'initialized';
+
     public const ON_CONNECT = 'connection';
+
     public const ON_DISCONNECT = 'disconnect';
+
     protected const TIMEOUT_ON_FAILURE = 60;
 
-    /** @var CurlAsync */
-    protected $curl;
+    protected CurlAsync $curl;
 
-    /** @var LoggerInterface */
-    protected $parentLogger;
+    protected LoggerInterface $parentLogger;
 
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    /** @var ?LoopInterface */
-    protected $loop;
+    protected ?LoopInterface $loop = null;
 
-    /** @var ServerSet */
-    protected $servers;
+    protected ServerSet $servers;
 
     /** @var ApiConnection[]  $vcenterId => ApiConnection */
-    protected $apiConnections = [];
+    protected array $apiConnections = [];
 
     /** @var array<int, array<int, ServerInfo>> [vcenterId => [serverId => ServerInfo, ...] */
-    protected $vCenterCandidates = [];
+    protected array $vCenterCandidates = [];
 
     /** @var array<int, Deferred> [serverId => Deferred] */
-    protected $initializations = [];
+    protected array $initializations = [];
 
     /** @var array<int, TimerInterface> key is the serverId */
-    protected $failing = [];
+    protected array $failing = [];
 
     /** @var array<int, string> key is the serverId */
-    protected $failingErrorMessages = [];
+    protected array $failingErrorMessages = [];
 
-    /** @var ServerSet */
-    protected $appliedServers;
+    protected ServerSet $appliedServers;
 
     public function __construct(CurlAsync $curl, LoggerInterface $logger)
     {
@@ -66,7 +63,7 @@ public function __construct(CurlAsync $curl, LoggerInterface $logger)
         $this->appliedServers = $this->servers = new ServerSet();
     }
 
-    public function setServerSet(ServerSet $servers)
+    public function setServerSet(ServerSet $servers): void
     {
         if (!$servers->equals($this->servers)) {
             $this->servers = $servers;
@@ -111,10 +108,11 @@ public function getApiConnectionOverview(): array
         return $connections;
     }
 
-    protected function applyServers(ServerSet $servers)
+    protected function applyServers(ServerSet $servers): void
     {
         if ($servers->equals($this->appliedServers)) {
             $this->logger->debug('Server Set is unchanged');
+
             return;
         }
         $vCenterCandidates = [];
@@ -142,7 +140,7 @@ protected function applyServers(ServerSet $servers)
         $this->removeObsoleteFailingServers();
     }
 
-    protected function startInitialization(ServerInfo $server)
+    protected function startInitialization(ServerInfo $server): void
     {
         $serverId = $server->getServerId();
         $this->initializations[$serverId] = $initialize = $this->initialize($server);
@@ -180,25 +178,20 @@ protected function initialize(ServerInfo $server): Deferred
                 });
         });
         $apiConnection->on(ApiConnection::ON_ERROR, function (ApiConnection $connection) use ($server, $deferred) {
+            $message = 'Initialization failed';
             if ($error = $connection->getLastErrorMessage()) {
-                $message = "Initialization failed: $error";
-            } else {
-                $message = 'Initialization failed';
+                $message .= ": $error";
             }
             $deferred->reject(new Exception($message));
             $this->setFailed($server, $message);
         });
-        $this->logger->notice(sprintf(
-            'initializing server %d: %s',
-            $server->getServerId(),
-            $server->getIdentifier()
-        ));
+        $this->logger->notice(sprintf('initializing server %d: %s', $server->getServerId(), $server->getIdentifier()));
         $apiConnection->run($this->loop);
 
         return $deferred;
     }
 
-    protected function launchNewlyConfiguredVCenters()
+    protected function launchNewlyConfiguredVCenters(): void
     {
         foreach ($this->vCenterCandidates as $vCenterId => $servers) {
             /** @var ServerInfo $server */
@@ -241,7 +234,7 @@ protected function launchNewlyConfiguredVCenters()
         }
     }
 
-    protected function setFailed(ServerInfo $server, ?string $message = 'unknown error')
+    protected function setFailed(ServerInfo $server, ?string $message = 'unknown error'): void
     {
         $serverId = $server->getServerId();
         $this->logger->warning(sprintf(
@@ -259,6 +252,7 @@ protected function setFailed(ServerInfo $server, ?string $message = 'unknown err
                     'Not retrying %s, connection has been removed',
                     $server->getIdentifier()
                 ));
+
                 return;
             }
             $this->loop->cancelTimer($this->failing[$serverId]);
@@ -292,7 +286,7 @@ protected function listAppliedServers(): array
         return $list;
     }
 
-    protected function removeObsoleteFailingServers()
+    protected function removeObsoleteFailingServers(): void
     {
         $serverMap = $this->listAppliedServers();
         foreach ($this->failing as $serverId => $timer) {
@@ -305,7 +299,7 @@ protected function removeObsoleteFailingServers()
         }
     }
 
-    protected function removeUnConfiguredApiConnections()
+    protected function removeUnConfiguredApiConnections(): void
     {
         $remove = [];
         foreach ($this->apiConnections as $vCenterId => $connection) {
@@ -331,13 +325,13 @@ protected function createApiConnection(ServerInfo $server): ApiConnection
         return new ApiConnection($this->curl, $server, $this->parentLogger);
     }
 
-    public function run(LoopInterface $loop)
+    public function run(LoopInterface $loop): void
     {
         $this->loop = $loop;
         $this->applyServers($this->servers);
     }
 
-    public function stop()
+    public function stop(): void
     {
         $this->logger->notice('Stopping API connection handler');
         $this->applyServers($this->servers = new ServerSet());
diff --git a/library/Vspheredb/Polling/CookieStore.php b/library/Vspheredb/Polling/CookieStore.php
index 00256368..2a5ffa69 100644
--- a/library/Vspheredb/Polling/CookieStore.php
+++ b/library/Vspheredb/Polling/CookieStore.php
@@ -12,19 +12,15 @@
 
 class CookieStore
 {
-    /** @var string */
-    private $cacheDir;
+    private string $cacheDir;
 
-    /** @var string */
-    private $cookieFile;
+    private string $cookieFile;
 
-    /** @var array */
-    private $cookies = [];
+    private array $cookies = [];
 
-    /** @var LoggerInterface */
-    private $logger;
+    private LoggerInterface $logger;
 
-    public function __construct($cacheDir, ServerInfo $serverInfo, LoggerInterface $logger)
+    public function __construct(string $cacheDir, ServerInfo $serverInfo, LoggerInterface $logger)
     {
         $this->cacheDir = $cacheDir;
         $this->logger = $logger;
@@ -37,12 +33,12 @@ public function __construct($cacheDir, ServerInfo $serverInfo, LoggerInterface $
     /**
      * @return bool
      */
-    public function hasCookies()
+    public function hasCookies(): bool
     {
-        return !empty($this->cookies);
+        return ! empty($this->cookies);
     }
 
-    public function setCookies(array $cookies)
+    public function setCookies(array $cookies): void
     {
         if ($cookies !== $this->cookies) {
             $this->logger->notice('Cookies changed, storing new ones');
@@ -54,7 +50,7 @@ public function setCookies(array $cookies)
     /**
      * Discard our Cookie
      */
-    public function forgetCookies()
+    public function forgetCookies(): void
     {
         $this->cookies = [];
         if (file_exists($this->cookieFile)) {
@@ -62,7 +58,7 @@ public function forgetCookies()
         }
     }
 
-    public function getCookies()
+    public function getCookies(): false|array
     {
         if (file_exists($this->cookieFile . '.fake')) {
             return file($this->cookieFile . '.fake', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
diff --git a/library/Vspheredb/Polling/CurlOptions.php b/library/Vspheredb/Polling/CurlOptions.php
index 39f0cb63..0b9f4f1a 100644
--- a/library/Vspheredb/Polling/CurlOptions.php
+++ b/library/Vspheredb/Polling/CurlOptions.php
@@ -16,31 +16,14 @@ class CurlOptions
     /** @var array */
     public const PROXY_TYPES = [
         'HTTP'   => CURLPROXY_HTTP,
-        'SOCKS5' => CURLPROXY_SOCKS5,
+        'SOCKS5' => CURLPROXY_SOCKS5
     ];
 
-    public static function forServerInfo(ServerInfo $server)
+    public static function forServerInfo(ServerInfo $server): array
     {
         $host = $server->get('host');
-        if (preg_match('/^(.+?):(\d{1,5})$/', $host, $match)) {
-            $host = $match[1];
-            $port = (int) $match[2];
-        } else {
-            $port = null;
-        }
-        $options = [
-            CURLOPT_HTTPHEADER => [
-                // Host header disabled for now, see #496
-                // "Host: $host",
-                'Expect:',
-                'User-Agent: Icinga-vSphereDB/1.8',
-            ]
-        ];
-
-        // Unused, we're authenticating via SOAP
-        // if (null !== ($username = $server->get('username'))) {
-        //     $options[CURLOPT_USERPWD] = sprintf('%s:%s', $username, $server->get('password'));
-        // }
+        $port = preg_match('/^(.+?):(\d{1,5})$/', $host, $match) ? (int) $match[2] : null;
+        $options[CURLOPT_HTTPHEADER] = ['Expect:', 'User-Agent: Icinga-vSphereDB/1.8'];
 
         if ($proxyType = $server->get('proxy_type')) {
             // TODO: Depending on the PHP and Curl version, we might want to support HTTPS proxies
@@ -70,7 +53,7 @@ public static function forServerInfo(ServerInfo $server)
         return $options;
     }
 
-    protected static function wantCurlProxyType($type)
+    protected static function wantCurlProxyType(int|string $type): int
     {
         if (is_int($type)) {
             if (in_array($type, self::PROXY_TYPES, true)) {
diff --git a/library/Vspheredb/Polling/PerformanceCounterLookup/CounterLookup.php b/library/Vspheredb/Polling/PerformanceCounterLookup/CounterLookup.php
index 23083a8b..ca270d57 100644
--- a/library/Vspheredb/Polling/PerformanceCounterLookup/CounterLookup.php
+++ b/library/Vspheredb/Polling/PerformanceCounterLookup/CounterLookup.php
@@ -7,16 +7,18 @@
 interface CounterLookup
 {
     /**
-     * @param UuidInterface $vCenterUuid
+     * @param ?UuidInterface $vCenterUuid
+     *
      * @return array
      */
-    public function fetchTags(?UuidInterface $vCenterUuid = null);
+    public function fetchTags(?UuidInterface $vCenterUuid = null): array;
 
     /**
      * Hint: instance = '*' -> all instances, instance = '' -> aggregated
      *
-     * @param UuidInterface $vCenterUuid
+     * @param ?UuidInterface $vCenterUuid
+     *
      * @return array
      */
-    public function fetchRequiredMetricInstances(?UuidInterface $vCenterUuid = null);
+    public function fetchRequiredMetricInstances(?UuidInterface $vCenterUuid = null): array;
 }
diff --git a/library/Vspheredb/Polling/PerformanceCounterLookup/CounterMap.php b/library/Vspheredb/Polling/PerformanceCounterLookup/CounterMap.php
index a7349729..fe472467 100644
--- a/library/Vspheredb/Polling/PerformanceCounterLookup/CounterMap.php
+++ b/library/Vspheredb/Polling/PerformanceCounterLookup/CounterMap.php
@@ -4,16 +4,20 @@
 
 use Icinga\Module\Vspheredb\Polling\PerformanceSet\PerformanceSet;
 use Ramsey\Uuid\UuidInterface;
+use Zend_Db_Adapter_Abstract;
 
 abstract class CounterMap
 {
-    public static function fetchCounters($db, PerformanceSet $set, UuidInterface $vCenterUuid)
-    {
+    public static function fetchCounters(
+        Zend_Db_Adapter_Abstract $db,
+        PerformanceSet $set,
+        UuidInterface $vCenterUuid
+    ): array {
         $query = $db
             ->select()
             ->from('performance_counter', [
                 'v' => 'counter_key',
-                'k' => 'name',
+                'k' => 'name'
             ])
             ->where('vcenter_uuid = ?', $vCenterUuid->getBytes())
             ->where('group_name = ?', $set->getCountersGroup())
diff --git a/library/Vspheredb/Polling/PerformanceCounterLookup/DefaultCounterLookup.php b/library/Vspheredb/Polling/PerformanceCounterLookup/DefaultCounterLookup.php
index 5f154d2e..813468ad 100644
--- a/library/Vspheredb/Polling/PerformanceCounterLookup/DefaultCounterLookup.php
+++ b/library/Vspheredb/Polling/PerformanceCounterLookup/DefaultCounterLookup.php
@@ -2,30 +2,32 @@
 
 namespace Icinga\Module\Vspheredb\Polling\PerformanceCounterLookup;
 
-use gipfl\ZfDb\Adapter\Adapter;
 use Ramsey\Uuid\Uuid;
 use Ramsey\Uuid\UuidInterface;
 use RuntimeException;
+use Zend_Db_Adapter_Abstract;
+use Zend_Db_Select;
 
 abstract class DefaultCounterLookup implements CounterLookup
 {
     /**
-     * @var Adapter|\Zend_Db_Adapter_Abstract
+     * @var Zend_Db_Adapter_Abstract
      */
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
 
-    protected $tagColumns;
+    /** @var ?string[] */
+    protected ?array $tagColumns = null;
 
-    protected $objectKey;
+    protected ?string $objectKey = null;
 
-    protected $instanceKey;
+    protected ?string $instanceKey = null;
 
-    protected $staticInstanceKey;
+    protected ?string $staticInstanceKey = null;
 
     /**
-     * @param Adapter|\Zend_Db_Adapter_Abstract $db
+     * @param Zend_Db_Adapter_Abstract $db
      */
-    public function __construct($db)
+    public function __construct(Zend_Db_Adapter_Abstract $db)
     {
         $this->db = $db;
     }
@@ -65,27 +67,21 @@ public function fetchRequiredMetricInstances(?UuidInterface $vCenterUuid = null)
     {
         if ($this->hasInstanceKey()) {
             return static::explodeInstances($this->db->fetchPairs($this->prepareInstancesQuery($vCenterUuid)));
-        } else {
-            return $this->db->fetchPairs($this->prepareInstancesQuery($vCenterUuid));
         }
+
+        return $this->db->fetchPairs($this->prepareInstancesQuery($vCenterUuid));
     }
 
-    abstract protected function prepareBaseQuery(UuidInterface $vCenterUuid);
+    abstract protected function prepareBaseQuery(UuidInterface $vCenterUuid): Zend_Db_Select;
 
-    abstract protected function prepareInstancesQuery(UuidInterface $vCenterUuid);
+    abstract protected function prepareInstancesQuery(UuidInterface $vCenterUuid): Zend_Db_Select;
 
     protected static function explodeInstances($queryResult): array
     {
-        $result = [];
-
-        foreach ($queryResult as $key => $value) {
-            $result[$key] = explode(',', $value);
-        }
-
-        return $result;
+        return array_map(fn ($value) => explode(',', $value), $queryResult);
     }
 
-    protected function getTagColumns()
+    protected function getTagColumns(): array
     {
         if ($this->tagColumns === null) {
             throw $this->missingPropertyError('tagColumns');
@@ -94,7 +90,7 @@ protected function getTagColumns()
         return $this->tagColumns;
     }
 
-    protected function getObjectKey()
+    protected function getObjectKey(): string
     {
         if ($this->objectKey === null) {
             throw $this->missingPropertyError('objectKey');
@@ -103,7 +99,7 @@ protected function getObjectKey()
         return $this->objectKey;
     }
 
-    protected function getInstanceKey()
+    protected function getInstanceKey(): string
     {
         if ($this->instanceKey === null) {
             throw $this->missingPropertyError('instanceKey');
@@ -112,10 +108,10 @@ protected function getInstanceKey()
         return $this->instanceKey;
     }
 
-    protected function convertResultRowUuidsToText($row)
+    protected function convertResultRowUuidsToText($row): void
     {
         foreach (array_keys((array) $row) as $key) {
-            if ($key === 'uuid' || substr($key, -5) === '_uuid') {
+            if ($key === 'uuid' || str_ends_with($key, '_uuid')) {
                 if (strlen($row->$key) === 16) {
                     $row->$key = Uuid::fromBytes($row->$key)->toString();
                 }
diff --git a/library/Vspheredb/Polling/PerformanceCounterLookup/HostCounterLookup.php b/library/Vspheredb/Polling/PerformanceCounterLookup/HostCounterLookup.php
index 6261f01c..c9e2a3df 100644
--- a/library/Vspheredb/Polling/PerformanceCounterLookup/HostCounterLookup.php
+++ b/library/Vspheredb/Polling/PerformanceCounterLookup/HostCounterLookup.php
@@ -3,28 +3,29 @@
 namespace Icinga\Module\Vspheredb\Polling\PerformanceCounterLookup;
 
 use Ramsey\Uuid\UuidInterface;
+use Zend_Db_Select;
 
 class HostCounterLookup extends DefaultCounterLookup
 {
-    protected $objectKey = 'host_moref';
+    protected ?string $objectKey = 'host_moref';
 
-    protected $tagColumns = [
+    protected ?array $tagColumns = [
         'host_uuid'    => 'o.uuid',
         'sysinfo_uuid' => 'hs.sysinfo_uuid',
         'host_moref'   => 'o.moref',
-        'host_name'    => 'o.object_name',
+        'host_name'    => 'o.object_name'
     ];
 
-    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         return $this->prepareBaseQuery($vCenterUuid)
             ->columns([
                 'o.moref',
-                'nix' => '(NULL)',
+                'nix' => '(NULL)'
             ]);
     }
 
-    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         $query = $this->db->select()->from(['o' => 'object'], [])
             ->join(['hs' => 'host_system'], 'o.uuid = hs.uuid', [])
diff --git a/library/Vspheredb/Polling/PerformanceCounterLookup/HostNetworkCounterLookup.php b/library/Vspheredb/Polling/PerformanceCounterLookup/HostNetworkCounterLookup.php
index 45daf78a..7f5ea355 100644
--- a/library/Vspheredb/Polling/PerformanceCounterLookup/HostNetworkCounterLookup.php
+++ b/library/Vspheredb/Polling/PerformanceCounterLookup/HostNetworkCounterLookup.php
@@ -3,34 +3,36 @@
 namespace Icinga\Module\Vspheredb\Polling\PerformanceCounterLookup;
 
 use Ramsey\Uuid\UuidInterface;
+use Zend_Db_Select;
 
 class HostNetworkCounterLookup extends DefaultCounterLookup
 {
-    protected $objectKey = 'host_moref';
-    protected $instanceKey = 'device_label';
+    protected ?string $objectKey = 'host_moref';
 
-    protected $tagColumns = [
+    protected ?string $instanceKey = 'device_label';
+
+    protected ?array $tagColumns = [
         'host_uuid'    => 'o.uuid',
         'sysinfo_uuid' => 'hs.sysinfo_uuid',
         'host_moref'   => 'o.moref',
         'host_name'    => 'o.object_name',
         // 'pnic_key'     => 'hpn.nic_key', -> key-vim.host.PhysicalNic-vmnic0, ugly
-        'device_label' => 'hpn.device',
+        'device_label' => 'hpn.device'
     ];
 
-    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         return $this->prepareBaseQuery($vCenterUuid)
             ->columns([
                 'o.moref',
-                'device' => "GROUP_CONCAT(hpn.device SEPARATOR ',')",
+                'device' => "GROUP_CONCAT(hpn.device SEPARATOR ',')"
             ])
             ->group('hs.uuid')
             ->order('hs.uuid')
             ->order('hpn.device');
     }
 
-    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         $query = $this->db->select()->from(['o' => 'object'], [])
             ->join(['hs' => 'host_system'], 'o.uuid = hs.uuid', [])
diff --git a/library/Vspheredb/Polling/PerformanceCounterLookup/VmCounterLookup.php b/library/Vspheredb/Polling/PerformanceCounterLookup/VmCounterLookup.php
index 1f8d73a4..1e6fd7df 100644
--- a/library/Vspheredb/Polling/PerformanceCounterLookup/VmCounterLookup.php
+++ b/library/Vspheredb/Polling/PerformanceCounterLookup/VmCounterLookup.php
@@ -3,28 +3,29 @@
 namespace Icinga\Module\Vspheredb\Polling\PerformanceCounterLookup;
 
 use Ramsey\Uuid\UuidInterface;
+use Zend_Db_Select;
 
 class VmCounterLookup extends DefaultCounterLookup
 {
-    protected $objectKey = 'vm_moref';
+    protected ?string $objectKey = 'vm_moref';
 
-    protected $tagColumns = [
+    protected ?array $tagColumns = [
         'vm_uuid' => 'o.uuid',
         'vm_name' => 'o.object_name',
         'vm_guest_host_name' => 'vm.guest_host_name',
-        'vm_moref' => 'o.moref',
+        'vm_moref' => 'o.moref'
     ];
 
-    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         return $this->prepareBaseQuery($vCenterUuid)
             ->columns([
                 'o.moref',
-                'nix' => '(NULL)',
+                'nix' => '(NULL)'
             ]);
     }
 
-    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         $query = $this->db->select()->from(['o' => 'object'], [])
             ->join(['vm' => 'virtual_machine'], 'o.uuid = vm.uuid', [])
diff --git a/library/Vspheredb/Polling/PerformanceCounterLookup/VmDiskCounterLookup.php b/library/Vspheredb/Polling/PerformanceCounterLookup/VmDiskCounterLookup.php
index 878a5c7b..0c5e1e1a 100644
--- a/library/Vspheredb/Polling/PerformanceCounterLookup/VmDiskCounterLookup.php
+++ b/library/Vspheredb/Polling/PerformanceCounterLookup/VmDiskCounterLookup.php
@@ -3,6 +3,7 @@
 namespace Icinga\Module\Vspheredb\Polling\PerformanceCounterLookup;
 
 use Ramsey\Uuid\UuidInterface;
+use Zend_Db_Select;
 
 class VmDiskCounterLookup extends DefaultCounterLookup
 {
@@ -12,28 +13,30 @@ class VmDiskCounterLookup extends DefaultCounterLookup
     . " ELSE 'scsi' END"
     . " || vmhc.bus_number || ':' || vmhw.unit_number";
 
-    protected $objectKey = 'vm_moref';
-    protected $instanceKey = 'disk_hardware_key';
-    protected $tagColumns = [
+    protected ?string $objectKey = 'vm_moref';
+
+    protected ?string $instanceKey = 'disk_hardware_key';
+
+    protected ?array $tagColumns = [
         'vm_uuid' => 'o.uuid',
         'vm_name' => 'o.object_name',
         'vm_guest_host_name' => 'vm.guest_host_name',
         'vm_moref' => 'o.moref',
         'disk_hardware_key' => '(' . self::INSTANCE_KEY_EXPRESSION . ')',
-        'disk_hardware_label' => 'vmhw.label',
+        'disk_hardware_label' => 'vmhw.label'
     ];
 
-    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         return $this->prepareBaseQuery($vCenterUuid)
             ->columns([
                 'o.moref',
-                'GROUP_CONCAT(' . self::INSTANCE_KEY_EXPRESSION . " SEPARATOR ',')",
+                'GROUP_CONCAT(' . self::INSTANCE_KEY_EXPRESSION . " SEPARATOR ',')"
             ])
             ->group('vm.uuid');
     }
 
-    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         $query = $this->db->select()->from(['o' => 'object'], [])
             ->join(['vm' => 'virtual_machine'], 'o.uuid = vm.uuid', [])
diff --git a/library/Vspheredb/Polling/PerformanceCounterLookup/VmNetworkCounterLookup.php b/library/Vspheredb/Polling/PerformanceCounterLookup/VmNetworkCounterLookup.php
index a36b3a16..ebe54940 100644
--- a/library/Vspheredb/Polling/PerformanceCounterLookup/VmNetworkCounterLookup.php
+++ b/library/Vspheredb/Polling/PerformanceCounterLookup/VmNetworkCounterLookup.php
@@ -3,12 +3,15 @@
 namespace Icinga\Module\Vspheredb\Polling\PerformanceCounterLookup;
 
 use Ramsey\Uuid\UuidInterface;
+use Zend_Db_Select;
 
 class VmNetworkCounterLookup extends DefaultCounterLookup
 {
-    protected $objectKey = 'vm_moref';
-    protected $instanceKey = 'interface_hardware_key';
-    protected $tagColumns = [
+    protected ?string $objectKey = 'vm_moref';
+
+    protected ?string $instanceKey = 'interface_hardware_key';
+
+    protected ?array $tagColumns = [
         'vm_uuid'                => 'o.uuid',
         'vm_moref'               => 'o.moref',
         'vm_name'                => 'o.object_name',
@@ -16,22 +19,22 @@ class VmNetworkCounterLookup extends DefaultCounterLookup
         'interface_hardware_key' => 'vna.hardware_key',
         // 'parent_name'     => 'po.object_name',
         'interface_label'        => 'vh.label',
-        // 'portgroup_name'  => 'pgo.object_name',
+        // 'portgroup_name'  => 'pgo.object_name'
     ];
 
-    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareInstancesQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         return $this->prepareBaseQuery($vCenterUuid)
             ->columns([
                 'o.moref',
-                'hardware_key' => "GROUP_CONCAT(vna.hardware_key SEPARATOR ',')",
+                'hardware_key' => "GROUP_CONCAT(vna.hardware_key SEPARATOR ',')"
             ])
             ->group('vm.uuid')
             ->order('vm.runtime_host_uuid')
             ->order('vna.hardware_key');
     }
 
-    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null)
+    protected function prepareBaseQuery(?UuidInterface $vCenterUuid = null): Zend_Db_Select
     {
         $query = $this->db->select()->from(['o' => 'object'], [])
             ->join(['vm' => 'virtual_machine'], 'o.uuid = vm.uuid', [])
diff --git a/library/Vspheredb/Polling/PerformanceQuerySpecHelper.php b/library/Vspheredb/Polling/PerformanceQuerySpecHelper.php
index cc85ac7b..0f924847 100644
--- a/library/Vspheredb/Polling/PerformanceQuerySpecHelper.php
+++ b/library/Vspheredb/Polling/PerformanceQuerySpecHelper.php
@@ -11,19 +11,20 @@ abstract class PerformanceQuerySpecHelper
 {
     /**
      * @param string $objectType 'HostSystem', 'VirtualMachine'...
-     * @param array $counters  [counterKey => name, ...]
-     * @param $objectWithInstances [vm-123 => [scsi0:0, ...], ...]. To test: * would be all instances
+     * @param array $counters [counterKey => name, ...]
+     * @param array $objectWithInstances [vm-123 => [scsi0:0, ...], ...]. To test: * would be all instances
      * @param int $count Defaults to 180. We have 1h in a 20s interval. 3600 / 20 = 180
      * @param int $interval Defaults to 20s, "realtime"
+     *
      * @return PerfQuerySpec[]
      */
     public static function prepareQuerySpec(
-        $objectType,
-        $counters,
-        $objectWithInstances,
-        $count = 180,
-        $interval = 20
-    ) {
+        string $objectType,
+        array $counters,
+        array $objectWithInstances,
+        int $count = 180,
+        int $interval = 20
+    ): array {
         $duration = $interval * ($count);
         $now = floor(time() / $interval) * $interval;
         $start = Util::makeDateTime($now - $duration);
diff --git a/library/Vspheredb/Polling/PerformanceSet/DatastoreDiskPerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/DatastoreDiskPerformanceSet.php
index e00ccfd7..a00483c1 100644
--- a/library/Vspheredb/Polling/PerformanceSet/DatastoreDiskPerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/DatastoreDiskPerformanceSet.php
@@ -4,13 +4,16 @@
 
 class DatastoreDiskPerformanceSet extends DefaultPerformanceSet
 {
-    protected $name = 'DatastoreDisk';
-    protected $objectType = 'Datastore';
-    protected $countersGroup = 'disk';
-    protected $counters = [
+    protected ?string $name = 'DatastoreDisk';
+
+    protected ?string $objectType = 'Datastore';
+
+    protected ?string $countersGroup = 'disk';
+
+    protected ?array $counters = [
         'capacity',
         'used',
         'provisioned',
-        'deltaused',
+        'deltaused'
     ];
 }
diff --git a/library/Vspheredb/Polling/PerformanceSet/DatastorePerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/DatastorePerformanceSet.php
index f86bc95f..5f9ee8b7 100644
--- a/library/Vspheredb/Polling/PerformanceSet/DatastorePerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/DatastorePerformanceSet.php
@@ -4,10 +4,13 @@
 
 class DatastorePerformanceSet extends DefaultPerformanceSet
 {
-    protected $name = 'Datastore';
-    protected $objectType = 'Datastore';
-    protected $countersGroup = 'datastore';
-    protected $counters = [
+    protected ?string $name = 'Datastore';
+
+    protected ?string $objectType = 'Datastore';
+
+    protected ?string $countersGroup = 'datastore';
+
+    protected ?array $counters = [
         'read',
         'write',
         'datastoreReadBytes',
@@ -15,6 +18,6 @@ class DatastorePerformanceSet extends DefaultPerformanceSet
         'datastoreReadIops',
         'datastoreWriteIops',
         'totalReadLatency',
-        'totalWriteLatency',
+        'totalWriteLatency'
     ];
 }
diff --git a/library/Vspheredb/Polling/PerformanceSet/DefaultPerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/DefaultPerformanceSet.php
index efeb5972..39430627 100644
--- a/library/Vspheredb/Polling/PerformanceSet/DefaultPerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/DefaultPerformanceSet.php
@@ -6,19 +6,19 @@
 
 abstract class DefaultPerformanceSet implements PerformanceSet
 {
-    /** @var string Name for this Performance Set */
-    protected $name;
+    /** @var ?string Name for this Performance Set */
+    protected ?string $name = null;
 
-    /** @var string vmWare Object Type */
-    protected $objectType;
+    /** @var ?string vmWare Object Type */
+    protected ?string $objectType = null;
 
-    /** @var string vmWare Counters Group */
-    protected $countersGroup;
+    /** @var ?string vmWare Counters Group */
+    protected ?string $countersGroup = null;
 
-    /** @var string[] Required counters by name */
-    protected $counters;
+    /** @var ?string[] Required counters by name */
+    protected ?array $counters = null;
 
-    public function getName()
+    public function getName(): string
     {
         if ($this->name === null) {
             throw $this->missingPropertyError('name');
@@ -27,7 +27,7 @@ public function getName()
         return $this->name;
     }
 
-    public function getObjectType()
+    public function getObjectType(): string
     {
         if ($this->objectType === null) {
             throw $this->missingPropertyError('objectType');
@@ -36,7 +36,7 @@ public function getObjectType()
         return $this->objectType;
     }
 
-    public function getCountersGroup()
+    public function getCountersGroup(): string
     {
         if ($this->countersGroup === null) {
             throw $this->missingPropertyError('countersGroup');
@@ -45,7 +45,7 @@ public function getCountersGroup()
         return $this->countersGroup;
     }
 
-    public function getCounters()
+    public function getCounters(): array
     {
         if ($this->counters === null) {
             throw $this->missingPropertyError('counters');
@@ -56,9 +56,10 @@ public function getCounters()
 
     /**
      * @param $property
+     *
      * @return RuntimeException
      */
-    protected function missingPropertyError($property)
+    protected function missingPropertyError($property): RuntimeException
     {
         return new RuntimeException(sprintf(
             '$%s is required when extending %s, missing in %s',
diff --git a/library/Vspheredb/Polling/PerformanceSet/HostCpuPerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/HostCpuPerformanceSet.php
index f4708a03..768f3967 100644
--- a/library/Vspheredb/Polling/PerformanceSet/HostCpuPerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/HostCpuPerformanceSet.php
@@ -4,16 +4,19 @@
 
 class HostCpuPerformanceSet extends DefaultPerformanceSet
 {
-    protected $name = 'HostCpu';
-    protected $objectType = 'HostSystem';
-    protected $countersGroup = 'cpu';
-    protected $counters = [
+    protected ?string $name = 'HostCpu';
+
+    protected ?string $objectType = 'HostSystem';
+
+    protected ?string $countersGroup = 'cpu';
+
+    protected ?array $counters = [
         'coreUtilization',
         'demand',
         'latency',
         'readiness',
         'usage',
         'usagemhz',
-        'utilization',
+        'utilization'
     ];
 }
diff --git a/library/Vspheredb/Polling/PerformanceSet/HostMemoryPerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/HostMemoryPerformanceSet.php
index bfa9877a..b310f857 100644
--- a/library/Vspheredb/Polling/PerformanceSet/HostMemoryPerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/HostMemoryPerformanceSet.php
@@ -4,10 +4,13 @@
 
 class HostMemoryPerformanceSet extends DefaultPerformanceSet
 {
-    protected $name = 'HostMemory';
-    protected $objectType = 'HostSystem';
-    protected $countersGroup = 'mem';
-    protected $counters = [
+    protected ?string $name = 'HostMemory';
+
+    protected ?string $objectType = 'HostSystem';
+
+    protected ?string $countersGroup = 'mem';
+
+    protected ?array $counters = [
         'active',
         'usage',
         'totalCapacity',
@@ -16,6 +19,6 @@ class HostMemoryPerformanceSet extends DefaultPerformanceSet
         'swapout',
         'swapinRate',
         'swapoutRate',
-        'vmmemctl',
+        'vmmemctl'
     ];
 }
diff --git a/library/Vspheredb/Polling/PerformanceSet/HostNetworkPerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/HostNetworkPerformanceSet.php
index 4709dfd6..0c50fd3a 100644
--- a/library/Vspheredb/Polling/PerformanceSet/HostNetworkPerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/HostNetworkPerformanceSet.php
@@ -4,10 +4,13 @@
 
 class HostNetworkPerformanceSet extends DefaultPerformanceSet
 {
-    protected $name = 'HostNetworkAdapter';
-    protected $objectType = 'HostSystem';
-    protected $countersGroup = 'net';
-    protected $counters = [
+    protected ?string $name = 'HostNetworkAdapter';
+
+    protected ?string $objectType = 'HostSystem';
+
+    protected ?string $countersGroup = 'net';
+
+    protected ?array $counters = [
         // averaged alternative: received, transmitted, usage
         // TODO: evaluate net.usage
         'bytesRx',
@@ -21,6 +24,6 @@ class HostNetworkPerformanceSet extends DefaultPerformanceSet
         'droppedRx',
         'droppedTx',
         'errorsRx',
-        'errorsTx',
+        'errorsTx'
     ];
 }
diff --git a/library/Vspheredb/Polling/PerformanceSet/PerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/PerformanceSet.php
index ff5f3d9b..94810144 100644
--- a/library/Vspheredb/Polling/PerformanceSet/PerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/PerformanceSet.php
@@ -7,20 +7,20 @@ interface PerformanceSet
     /**
      * @return string
      */
-    public function getName();
+    public function getName(): string;
 
     /**
      * @return string
      */
-    public function getObjectType();
+    public function getObjectType(): string;
 
     /**
      * @return string
      */
-    public function getCountersGroup();
+    public function getCountersGroup(): string;
 
     /**
      * @return string[]
      */
-    public function getCounters();
+    public function getCounters(): array;
 }
diff --git a/library/Vspheredb/Polling/PerformanceSet/VmCpuPerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/VmCpuPerformanceSet.php
index 6c4bf8ce..9460b163 100644
--- a/library/Vspheredb/Polling/PerformanceSet/VmCpuPerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/VmCpuPerformanceSet.php
@@ -4,16 +4,19 @@
 
 class VmCpuPerformanceSet extends DefaultPerformanceSet
 {
-    protected $name = 'VmCpu';
-    protected $objectType = 'VirtualMachine';
-    protected $countersGroup = 'cpu';
-    protected $counters = [
+    protected ?string $name = 'VmCpu';
+
+    protected ?string $objectType = 'VirtualMachine';
+
+    protected ?string $countersGroup = 'cpu';
+
+    protected ?array $counters = [
         'coreUtilization',
         'demand',
         'latency',
         'readiness',
         'usage',
         'usagemhz',
-        'utilization',
+        'utilization'
     ];
 }
diff --git a/library/Vspheredb/Polling/PerformanceSet/VmDiskPerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/VmDiskPerformanceSet.php
index dda0a9f5..01e7f008 100644
--- a/library/Vspheredb/Polling/PerformanceSet/VmDiskPerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/VmDiskPerformanceSet.php
@@ -4,10 +4,13 @@
 
 class VmDiskPerformanceSet extends DefaultPerformanceSet
 {
-    protected $name = 'VirtualDisk';
-    protected $objectType = 'VirtualMachine';
-    protected $countersGroup = 'virtualDisk';
-    protected $counters = [
+    protected ?string $name = 'VirtualDisk';
+
+    protected ?string $objectType = 'VirtualMachine';
+
+    protected ?string $countersGroup = 'virtualDisk';
+
+    protected ?array $counters = [
         // 'busResets', -> not per instance
         // 'commandsAborted',  -> not per instance
         'numberReadAveraged', // rate, average
diff --git a/library/Vspheredb/Polling/PerformanceSet/VmMemoryPerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/VmMemoryPerformanceSet.php
index 543731ed..9130d697 100644
--- a/library/Vspheredb/Polling/PerformanceSet/VmMemoryPerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/VmMemoryPerformanceSet.php
@@ -4,10 +4,13 @@
 
 class VmMemoryPerformanceSet extends DefaultPerformanceSet
 {
-    protected $name = 'VmMemory';
-    protected $objectType = 'VirtualMachine';
-    protected $countersGroup = 'mem';
-    protected $counters = [
+    protected ?string $name = 'VmMemory';
+
+    protected ?string $objectType = 'VirtualMachine';
+
+    protected ?string $countersGroup = 'mem';
+
+    protected ?array $counters = [
         'active',
         'usage',
         'granted',
@@ -16,6 +19,6 @@ class VmMemoryPerformanceSet extends DefaultPerformanceSet
         'swapout',
         'swapinRate',
         'swapoutRate',
-        'vmmemctl',
+        'vmmemctl'
     ];
 }
diff --git a/library/Vspheredb/Polling/PerformanceSet/VmNetworkPerformanceSet.php b/library/Vspheredb/Polling/PerformanceSet/VmNetworkPerformanceSet.php
index 65bff24f..102ddaa0 100644
--- a/library/Vspheredb/Polling/PerformanceSet/VmNetworkPerformanceSet.php
+++ b/library/Vspheredb/Polling/PerformanceSet/VmNetworkPerformanceSet.php
@@ -4,10 +4,13 @@
 
 class VmNetworkPerformanceSet extends DefaultPerformanceSet
 {
-    protected $name = 'VirtualNetworkAdapter';
-    protected $objectType = 'VirtualMachine';
-    protected $countersGroup = 'net';
-    protected $counters = [
+    protected ?string $name = 'VirtualNetworkAdapter';
+
+    protected ?string $objectType = 'VirtualMachine';
+
+    protected ?string $countersGroup = 'net';
+
+    protected ?array $counters = [
         'bytesRx', // rate / average / kiloBytesPerSecond
         'bytesTx',
         'packetsRx',
@@ -17,6 +20,6 @@ class VmNetworkPerformanceSet extends DefaultPerformanceSet
         'multicastRx',
         'multicastTx',
         'droppedRx',
-        'droppedTx',
+        'droppedTx'
     ];
 }
diff --git a/library/Vspheredb/Polling/PropertySet/ComputeResourcePropertySet.php b/library/Vspheredb/Polling/PropertySet/ComputeResourcePropertySet.php
index 4fd300b2..229eb4a1 100644
--- a/library/Vspheredb/Polling/PropertySet/ComputeResourcePropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/ComputeResourcePropertySet.php
@@ -6,7 +6,7 @@
 
 class ComputeResourcePropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('ComputeResource', [
@@ -18,7 +18,7 @@ public static function create()
                 'summary.numHosts',
                 // 'summary.overallStatus',
                 'summary.totalCpu',
-                'summary.totalMemory',
+                'summary.totalMemory'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/DatastorePropertySet.php b/library/Vspheredb/Polling/PropertySet/DatastorePropertySet.php
index c53e15fc..de05ea71 100644
--- a/library/Vspheredb/Polling/PropertySet/DatastorePropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/DatastorePropertySet.php
@@ -6,7 +6,7 @@
 
 class DatastorePropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('Datastore', [
diff --git a/library/Vspheredb/Polling/PropertySet/FullObjectListPropertySet.php b/library/Vspheredb/Polling/PropertySet/FullObjectListPropertySet.php
index 1769f9de..f6a4067e 100644
--- a/library/Vspheredb/Polling/PropertySet/FullObjectListPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/FullObjectListPropertySet.php
@@ -6,7 +6,7 @@
 
 class FullObjectListPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return static::propertySet([
             'Datacenter',
@@ -21,16 +21,17 @@ public static function create()
             'VirtualApp',
             'Network',
             'DistributedVirtualSwitch',
-            'DistributedVirtualPortgroup',
+            'DistributedVirtualPortgroup'
         ], ['name', 'parent', 'overallStatus', 'tag']);
     }
 
     /**
      * @param string[] $types
      * @param ?string[] $pathSet
+     *
      * @return PropertySpec[]
      */
-    public static function propertySet(array $types, ?array $pathSet = null)
+    public static function propertySet(array $types, ?array $pathSet = null): array
     {
         $propSet = [];
         foreach ($types as $type) {
diff --git a/library/Vspheredb/Polling/PropertySet/HostHardwarePropertySet.php b/library/Vspheredb/Polling/PropertySet/HostHardwarePropertySet.php
index 44701390..4c2c4c59 100644
--- a/library/Vspheredb/Polling/PropertySet/HostHardwarePropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/HostHardwarePropertySet.php
@@ -6,11 +6,11 @@
 
 class HostHardwarePropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('HostSystem', [
-                'hardware.pciDevice',
+                'hardware.pciDevice'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/HostHbaPropertySet.php b/library/Vspheredb/Polling/PropertySet/HostHbaPropertySet.php
index d2fcc731..e7c915a1 100644
--- a/library/Vspheredb/Polling/PropertySet/HostHbaPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/HostHbaPropertySet.php
@@ -6,11 +6,11 @@
 
 class HostHbaPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('HostSystem', [
-                'config.storageDevice.hostBusAdapter',
+                'config.storageDevice.hostBusAdapter'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/HostNetworkPropertySet.php b/library/Vspheredb/Polling/PropertySet/HostNetworkPropertySet.php
index 39f10850..d42d56e7 100644
--- a/library/Vspheredb/Polling/PropertySet/HostNetworkPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/HostNetworkPropertySet.php
@@ -6,11 +6,11 @@
 
 class HostNetworkPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('HostSystem', [
-                'config.network',
+                'config.network'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/HostPhysicalNicPropertySet.php b/library/Vspheredb/Polling/PropertySet/HostPhysicalNicPropertySet.php
index 4e99d514..04818cdb 100644
--- a/library/Vspheredb/Polling/PropertySet/HostPhysicalNicPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/HostPhysicalNicPropertySet.php
@@ -6,11 +6,11 @@
 
 class HostPhysicalNicPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('HostSystem', [
-                'config.network.pnic',
+                'config.network.pnic'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/HostQuickStatsPropertySet.php b/library/Vspheredb/Polling/PropertySet/HostQuickStatsPropertySet.php
index 8149e59c..8d3553b2 100644
--- a/library/Vspheredb/Polling/PropertySet/HostQuickStatsPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/HostQuickStatsPropertySet.php
@@ -6,7 +6,7 @@
 
 class HostQuickStatsPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('HostSystem', [
@@ -14,7 +14,7 @@ public static function create()
                 'summary.quickStats.distributedMemoryFairness',
                 'summary.quickStats.overallCpuUsage',
                 'summary.quickStats.overallMemoryUsage',
-                'summary.quickStats.uptime',
+                'summary.quickStats.uptime'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/HostSensorsPropertySet.php b/library/Vspheredb/Polling/PropertySet/HostSensorsPropertySet.php
index c6f28aa4..aabff90b 100644
--- a/library/Vspheredb/Polling/PropertySet/HostSensorsPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/HostSensorsPropertySet.php
@@ -6,11 +6,11 @@
 
 class HostSensorsPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('HostSystem', [
-                'runtime.healthSystemRuntime.systemHealthInfo.numericSensorInfo',
+                'runtime.healthSystemRuntime.systemHealthInfo.numericSensorInfo'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/HostSystemPropertySet.php b/library/Vspheredb/Polling/PropertySet/HostSystemPropertySet.php
index 3cef9b46..e0454f1d 100644
--- a/library/Vspheredb/Polling/PropertySet/HostSystemPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/HostSystemPropertySet.php
@@ -6,7 +6,7 @@
 
 class HostSystemPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('HostSystem', [
@@ -35,7 +35,7 @@ public static function create()
 
                 'summary.hardware.memorySize',
                 'hardware.biosInfo.releaseDate',
-                'summary.hardware.otherIdentifyingInfo',
+                'summary.hardware.otherIdentifyingInfo'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/HostVirtualNicPropertySet.php b/library/Vspheredb/Polling/PropertySet/HostVirtualNicPropertySet.php
index 6252504c..f2589d41 100644
--- a/library/Vspheredb/Polling/PropertySet/HostVirtualNicPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/HostVirtualNicPropertySet.php
@@ -6,11 +6,11 @@
 
 class HostVirtualNicPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('HostSystem', [
-                'config.network.vnic',
+                'config.network.vnic'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/PropertySet.php b/library/Vspheredb/Polling/PropertySet/PropertySet.php
index 608f491e..7303416c 100644
--- a/library/Vspheredb/Polling/PropertySet/PropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/PropertySet.php
@@ -9,5 +9,5 @@ interface PropertySet
     /**
      * @return PropertySpec[]
      */
-    public static function create();
+    public static function create(): array;
 }
diff --git a/library/Vspheredb/Polling/PropertySet/StoragePodPropertySet.php b/library/Vspheredb/Polling/PropertySet/StoragePodPropertySet.php
index c2b3947e..5ffe98ba 100644
--- a/library/Vspheredb/Polling/PropertySet/StoragePodPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/StoragePodPropertySet.php
@@ -6,13 +6,13 @@
 
 class StoragePodPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('StoragePod', [
                 'name',
                 'summary.capacity',
-                'summary.freeSpace',
+                'summary.freeSpace'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/VirtualMachinePropertySet.php b/library/Vspheredb/Polling/PropertySet/VirtualMachinePropertySet.php
index 74197445..0b452a7f 100644
--- a/library/Vspheredb/Polling/PropertySet/VirtualMachinePropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/VirtualMachinePropertySet.php
@@ -6,7 +6,7 @@
 
 class VirtualMachinePropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('VirtualMachine', [
@@ -44,7 +44,7 @@ public static function create()
                 'config.cpuHotAddEnabled',
                 'config.memoryHotAddEnabled',
                 // 'runtime.bootTime',
-                // 'runtime.suspendTime',
+                // 'runtime.suspendTime'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/VmDatastoreUsagePropertySet.php b/library/Vspheredb/Polling/PropertySet/VmDatastoreUsagePropertySet.php
index 4de130b2..2c16a595 100644
--- a/library/Vspheredb/Polling/PropertySet/VmDatastoreUsagePropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/VmDatastoreUsagePropertySet.php
@@ -6,7 +6,7 @@
 
 class VmDatastoreUsagePropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('VirtualMachine', [
diff --git a/library/Vspheredb/Polling/PropertySet/VmDiskUsagePropertySet.php b/library/Vspheredb/Polling/PropertySet/VmDiskUsagePropertySet.php
index f0f9ab9a..b73cc2ab 100644
--- a/library/Vspheredb/Polling/PropertySet/VmDiskUsagePropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/VmDiskUsagePropertySet.php
@@ -6,11 +6,11 @@
 
 class VmDiskUsagePropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('VirtualMachine', [
-                'guest.disk',
+                'guest.disk'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/VmHardwarePropertySet.php b/library/Vspheredb/Polling/PropertySet/VmHardwarePropertySet.php
index 6790a8be..4f3ee94c 100644
--- a/library/Vspheredb/Polling/PropertySet/VmHardwarePropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/VmHardwarePropertySet.php
@@ -6,11 +6,11 @@
 
 class VmHardwarePropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('VirtualMachine', [
-                'config.hardware',
+                'config.hardware'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/VmQuickStatsPropertySet.php b/library/Vspheredb/Polling/PropertySet/VmQuickStatsPropertySet.php
index 343f52a7..eca9263a 100644
--- a/library/Vspheredb/Polling/PropertySet/VmQuickStatsPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/VmQuickStatsPropertySet.php
@@ -6,7 +6,7 @@
 
 class VmQuickStatsPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('VirtualMachine', [
@@ -29,7 +29,7 @@ public static function create()
                 'summary.quickStats.staticCpuEntitlement',
                 'summary.quickStats.staticMemoryEntitlement',
                 'summary.quickStats.swappedMemory',
-                'summary.quickStats.uptimeSeconds',
+                'summary.quickStats.uptimeSeconds'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/PropertySet/VmSnapshotPropertySet.php b/library/Vspheredb/Polling/PropertySet/VmSnapshotPropertySet.php
index 2b588815..f22433d3 100644
--- a/library/Vspheredb/Polling/PropertySet/VmSnapshotPropertySet.php
+++ b/library/Vspheredb/Polling/PropertySet/VmSnapshotPropertySet.php
@@ -6,11 +6,11 @@
 
 class VmSnapshotPropertySet implements PropertySet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             PropertySpec::create('VirtualMachine', [
-                'snapshot',
+                'snapshot'
             ])
         ];
     }
diff --git a/library/Vspheredb/Polling/RestApi.php b/library/Vspheredb/Polling/RestApi.php
index 84fa0771..d8f71bf5 100644
--- a/library/Vspheredb/Polling/RestApi.php
+++ b/library/Vspheredb/Polling/RestApi.php
@@ -23,27 +23,18 @@
 
 class RestApi
 {
-    /** @var CurlAsync */
-    protected $curl;
+    protected CurlAsync $curl;
 
-    /** @var CookieStore */
-    protected $sidStore;
+    protected CookieStore $sidStore;
 
-    /** @var ServerInfo */
-    protected $server;
+    protected ServerInfo $server;
 
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
     /** @var array[] */
-    protected $curlOptions;
-    /**
-     * @var VCenter
-     */
-    protected $vCenter;
+    protected array $curlOptions;
 
-    /** @var \Closure Will become obsolete with PHP 8.1 */
-    private $normalizeBatchResult;
+    protected VCenter $vCenter;
 
     public function __construct(
         ServerInfo $server,
@@ -57,10 +48,6 @@ public function __construct(
         $this->curl = $curl;
         $this->logger = $logger;
         $this->curlOptions = CurlOptions::forServerInfo($server);
-        $this->normalizeBatchResult = function ($result) {
-            // print_r($result);
-            return $this->normalizeBatchResult($result);
-        };
     }
 
     /**
@@ -169,11 +156,11 @@ function (ResponseInterface $result) {
                         //   "user":"username@VSPHERE.LOCAL"
                         // }
                         return true;
-                    } else {
-                        $this->logger->debug('REST API Session is no longer valid');
-                        $this->sidStore->forgetCookies();
-                        return false;
                     }
+                    $this->logger->debug('REST API Session is no longer valid');
+                    $this->sidStore->forgetCookies();
+
+                    return false;
                 }
             );
         }
@@ -188,7 +175,7 @@ protected function authenticate(): PromiseInterface
     {
         $request = new Request('POST', $this->apiUrl('session'), [
             'Accept' => 'application/json',
-            'Authorization' => $this->generateBasicAuthHeaderLine(),
+            'Authorization' => $this->generateBasicAuthHeaderLine()
         ]);
 
         return $this->curl->send($request, $this->curlOptions)
@@ -264,7 +251,7 @@ protected function send(RequestInterface $request): PromiseInterface
         return $this->curl->send($request, $this->curlOptions);
     }
 
-    public function getUsedCategories()
+    public function getUsedCategories(): PromiseInterface
     {
         // Test only, doesn't work
         return $this->post("cis/tagging/category?action=list-used-categories");
@@ -279,40 +266,36 @@ protected function taggingBatch(string $action, $body = null): PromiseInterface
     protected function get(string $url): PromiseInterface
     {
         return $this->send($this->request('GET', $this->apiUrl($url)))
-            ->then([$this, 'decodeResponse']);
+            ->then($this->decodeResponse(...));
     }
 
     protected function post(string $url, $body = null): PromiseInterface
     {
         return $this->send($this->request('POST', $this->apiUrl($url), $body))
-            ->then([$this, 'decodeResponse']);
+            ->then($this->decodeResponse(...));
     }
 
     protected function taggingBatchLegacy(string $action, $body = null): PromiseInterface
     {
         return $this->postLegacy("cis/tagging/batch?~action=$action", $body)
-            ->then($this->normalizeBatchResult);
+            ->then($this->normalizeBatchResult(...));
     }
 
     protected function getLegacy(string $url): PromiseInterface
     {
         return $this->send($this->request('GET', $this->legacyUrl($url)))
-            ->then([$this, 'decodeResponse'])
-            ->then([$this, 'requireValueProperty']);
+            ->then($this->decodeResponse(...))
+            ->then($this->requireValueProperty(...));
     }
 
     protected function postLegacy(string $url, $body = null): PromiseInterface
     {
         return $this->send($this->request('POST', $this->legacyUrl($url), $body))
-            ->then([$this, 'decodeResponse'])
-            ->then([$this, 'requireValueProperty']);
+            ->then($this->decodeResponse(...))
+            ->then($this->requireValueProperty(...));
     }
 
-    /**
-     * Will become protected, once we have ->decodeResponse(...) on 8.1
-     * @internal
-     */
-    public function decodeResponse(ResponseInterface $response)
+    protected function decodeResponse(ResponseInterface $response)
     {
         if ($response->getStatusCode() > 299) {
             throw new RuntimeException(
@@ -336,23 +319,18 @@ protected function legacyUrl(?string $path = null): string
 
     protected function addSessionIdToRequest(RequestInterface $request): RequestInterface
     {
-        if ($this->sidStore && $this->sidStore->hasCookies()) {
+        if ($this->sidStore->hasCookies()) {
             foreach ($this->sidStore->getCookies() as $sid) {
-                if (str_starts_with($request->getUri()->getPath(), '/rest/')) {
-                    $request = $request->withAddedHeader('cookie', "vmware-api-session-id=$sid");
-                } else {
-                    $request = $request->withAddedHeader('vmware-api-session-id', $sid);
-                }
+                $request = str_starts_with($request->getUri()->getPath(), '/rest/')
+                    ? $request->withAddedHeader('cookie', "vmware-api-session-id=$sid")
+                    : $request->withAddedHeader('vmware-api-session-id', $sid);
             }
         }
 
         return $request;
     }
 
-    /**
-     * @internal Will become protected with 8.1
-     */
-    public function requireValueProperty(stdClass $result)
+    protected function requireValueProperty(stdClass $result)
     {
         if (isset($result->error_type)) {
             // {
@@ -377,7 +355,7 @@ public function requireValueProperty(stdClass $result)
     protected function request(string $method, string $url, $body = null): RequestInterface
     {
         $headers = [
-            'Accept' => 'application/json',
+            'Accept' => 'application/json'
         ];
         if ($body) {
             $headers['Content-type'] = 'application/json';
diff --git a/library/Vspheredb/Polling/SelectSet/ComputeResourceSelectSet.php b/library/Vspheredb/Polling/SelectSet/ComputeResourceSelectSet.php
index 1d8121a5..bc1ef201 100644
--- a/library/Vspheredb/Polling/SelectSet/ComputeResourceSelectSet.php
+++ b/library/Vspheredb/Polling/SelectSet/ComputeResourceSelectSet.php
@@ -4,13 +4,13 @@
 
 class ComputeResourceSelectSet implements SelectSet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             GenericSpec::traverseFolder([
                 GenericSpec::TRAVERSE_DC_HOST_SYSTEMS
             ]),
-            GenericSpec::traverseDatacenterHosts(),
+            GenericSpec::traverseDatacenterHosts()
         ];
     }
 }
diff --git a/library/Vspheredb/Polling/SelectSet/DatastoreSelectSet.php b/library/Vspheredb/Polling/SelectSet/DatastoreSelectSet.php
index 58a715d1..a88989c5 100644
--- a/library/Vspheredb/Polling/SelectSet/DatastoreSelectSet.php
+++ b/library/Vspheredb/Polling/SelectSet/DatastoreSelectSet.php
@@ -6,15 +6,15 @@ class DatastoreSelectSet implements SelectSet
 {
     public const TRAVERSE_STORAGE_POD = 'TraverseStoragePod';
 
-    public static function create()
+    public static function create(): array
     {
         return [
             GenericSpec::traverseFolder([
                 GenericSpec::TRAVERSE_DC_DATA_STORES,
-                self::TRAVERSE_STORAGE_POD,
+                self::TRAVERSE_STORAGE_POD
             ]),
             GenericSpec::traverseDatacenterDataStores(),
-            GenericSpec::traverse(self::TRAVERSE_STORAGE_POD, 'StoragePod', 'childEntity'),
+            GenericSpec::traverse(self::TRAVERSE_STORAGE_POD, 'StoragePod', 'childEntity')
         ];
     }
 }
diff --git a/library/Vspheredb/Polling/SelectSet/DistributedVirtualPortgroupSelectSet.php b/library/Vspheredb/Polling/SelectSet/DistributedVirtualPortgroupSelectSet.php
index fb6043ba..481e0239 100644
--- a/library/Vspheredb/Polling/SelectSet/DistributedVirtualPortgroupSelectSet.php
+++ b/library/Vspheredb/Polling/SelectSet/DistributedVirtualPortgroupSelectSet.php
@@ -4,13 +4,13 @@
 
 class DistributedVirtualPortgroupSelectSet implements SelectSet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             GenericSpec::traverseFolder([
                 GenericSpec::TRAVERSE_DC_NETWORKS
             ]),
-            GenericSpec::traverseDatacenterNetworks(),
+            GenericSpec::traverseDatacenterNetworks()
         ];
     }
 }
diff --git a/library/Vspheredb/Polling/SelectSet/DistributedVirtualSwitchSelectSet.php b/library/Vspheredb/Polling/SelectSet/DistributedVirtualSwitchSelectSet.php
index bf60e522..3e1b11af 100644
--- a/library/Vspheredb/Polling/SelectSet/DistributedVirtualSwitchSelectSet.php
+++ b/library/Vspheredb/Polling/SelectSet/DistributedVirtualSwitchSelectSet.php
@@ -4,13 +4,13 @@
 
 class DistributedVirtualSwitchSelectSet implements SelectSet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             GenericSpec::traverseFolder([
                 GenericSpec::TRAVERSE_DC_NETWORKS
             ]),
-            GenericSpec::traverseDatacenterNetworks(),
+            GenericSpec::traverseDatacenterNetworks()
         ];
     }
 }
diff --git a/library/Vspheredb/Polling/SelectSet/FullSelectSet.php b/library/Vspheredb/Polling/SelectSet/FullSelectSet.php
index 3fd24abc..dd0f7853 100644
--- a/library/Vspheredb/Polling/SelectSet/FullSelectSet.php
+++ b/library/Vspheredb/Polling/SelectSet/FullSelectSet.php
@@ -15,7 +15,7 @@ class FullSelectSet implements SelectSet
     /**
      * @return SelectionSpec[]
      */
-    public static function create()
+    public static function create(): array
     {
         return [
             GenericSpec::traverseDatacenterHosts(),
@@ -29,7 +29,7 @@ public static function create()
                 GenericSpec::TRAVERSE_DC_VIRTUAL_MACHINES,
                 self::TRAVERSE_CR1,
                 self::TRAVERSE_CR2,
-                self::TRAVERSE_STORAGE_POD,
+                self::TRAVERSE_STORAGE_POD
             ]),
             GenericSpec::traverse(self::TRAVERSE_STORAGE_POD, 'StoragePod', 'childEntity'),
             GenericSpec::traverse(self::TRAVERSE_CR1, 'ComputeResource', 'resourcePool', [
@@ -39,7 +39,7 @@ public static function create()
                 // TraverseCR1 needs an array of two SelectionSpec objects, named
                 // TraverseRP1 and TraverseRP2
                 SelectionSpec::reference(self::TRAVERSE_RP1),
-                SelectionSpec::reference(self::TRAVERSE_RP2),
+                SelectionSpec::reference(self::TRAVERSE_RP2)
             ]),
             // TraverseCR2 can lead only to a HostSystem object, so there is no
             // need for it to have a selectSet array
@@ -49,9 +49,9 @@ public static function create()
                 // two paths out of ResourcePool, so it needs an array of two
                 // SelectionSpec objects, named TraverseRP1 and TraverseRP2
                 SelectionSpec::reference(self::TRAVERSE_RP1),
-                SelectionSpec::reference(self::TRAVERSE_RP2),
+                SelectionSpec::reference(self::TRAVERSE_RP2)
             ]),
-            GenericSpec::traverse(self::TRAVERSE_RP2, 'ResourcePool', 'vm'),
+            GenericSpec::traverse(self::TRAVERSE_RP2, 'ResourcePool', 'vm')
         ];
     }
 }
diff --git a/library/Vspheredb/Polling/SelectSet/GenericSpec.php b/library/Vspheredb/Polling/SelectSet/GenericSpec.php
index 67db6f1c..adeaef07 100644
--- a/library/Vspheredb/Polling/SelectSet/GenericSpec.php
+++ b/library/Vspheredb/Polling/SelectSet/GenericSpec.php
@@ -15,9 +15,10 @@ abstract class GenericSpec
 
     /**
      * @param string[] $specReferences
+     *
      * @return TraversalSpec
      */
-    public static function traverseFolder(array $specReferences = [])
+    public static function traverseFolder(array $specReferences = []): TraversalSpec
     {
         return self::traverse(self::TRAVERSE_FOLDER, 'Folder', 'childEntity', array_merge([
             self::TRAVERSE_FOLDER
@@ -28,31 +29,32 @@ public static function traverseFolder(array $specReferences = [])
      * @param string $name
      * @param string $type
      * @param string $path
+     *
      * @return TraversalSpec
      */
-    public static function traverseDatacenter($name, $type, $path)
+    public static function traverseDatacenter(string $name, string $type, string $path): TraversalSpec
     {
         return self::traverse($name, $type, $path, [
             self::TRAVERSE_FOLDER
         ]);
     }
 
-    public static function traverseDatacenterHosts()
+    public static function traverseDatacenterHosts(): TraversalSpec
     {
         return self::traverseDatacenter(self::TRAVERSE_DC_HOST_SYSTEMS, 'Datacenter', 'hostFolder');
     }
 
-    public static function traverseDatacenterVirtualMachines()
+    public static function traverseDatacenterVirtualMachines(): TraversalSpec
     {
         return self::traverseDatacenter(self::TRAVERSE_DC_VIRTUAL_MACHINES, 'Datacenter', 'vmFolder');
     }
 
-    public static function traverseDatacenterDataStores()
+    public static function traverseDatacenterDataStores(): TraversalSpec
     {
         return self::traverseDatacenter(self::TRAVERSE_DC_DATA_STORES, 'Datacenter', 'datastoreFolder');
     }
 
-    public static function traverseDatacenterNetworks()
+    public static function traverseDatacenterNetworks(): TraversalSpec
     {
         return self::traverseDatacenter(self::TRAVERSE_DC_NETWORKS, 'Datacenter', 'networkFolder');
     }
@@ -62,10 +64,15 @@ public static function traverseDatacenterNetworks()
      * @param string $type
      * @param string $path
      * @param ?SelectionSpec[]|string[] $selectionSet
+     *
      * @return TraversalSpec
      */
-    public static function traverse($name, $type, $path, ?array $selectionSet = null)
-    {
+    public static function traverse(
+        string $name,
+        string $type,
+        string $path,
+        ?array $selectionSet = null
+    ): TraversalSpec {
         if ($selectionSet) {
             foreach ($selectionSet as $key => $entry) {
                 if (is_string($entry)) {
diff --git a/library/Vspheredb/Polling/SelectSet/HostSystemSelectSet.php b/library/Vspheredb/Polling/SelectSet/HostSystemSelectSet.php
index 6d9d1f33..df64ed5f 100644
--- a/library/Vspheredb/Polling/SelectSet/HostSystemSelectSet.php
+++ b/library/Vspheredb/Polling/SelectSet/HostSystemSelectSet.php
@@ -11,15 +11,15 @@ class HostSystemSelectSet implements SelectSet
     /**
      * @return TraversalSpec[]
      */
-    public static function create()
+    public static function create(): array
     {
         return [
             GenericSpec::traverseFolder([
                 GenericSpec::TRAVERSE_DC_HOST_SYSTEMS,
-                self::TRAVERSE_COMPUTE_RESOURCES,
+                self::TRAVERSE_COMPUTE_RESOURCES
             ]),
             GenericSpec::traverseDatacenterHosts(),
-            GenericSpec::traverse(self::TRAVERSE_COMPUTE_RESOURCES, 'ComputeResource', 'host'),
+            GenericSpec::traverse(self::TRAVERSE_COMPUTE_RESOURCES, 'ComputeResource', 'host')
         ];
     }
 }
diff --git a/library/Vspheredb/Polling/SelectSet/SelectSet.php b/library/Vspheredb/Polling/SelectSet/SelectSet.php
index 8c8f8d33..30a16a8d 100644
--- a/library/Vspheredb/Polling/SelectSet/SelectSet.php
+++ b/library/Vspheredb/Polling/SelectSet/SelectSet.php
@@ -9,5 +9,5 @@ interface SelectSet
     /**
      * @return SelectionSpec[]
      */
-    public static function create();
+    public static function create(): array;
 }
diff --git a/library/Vspheredb/Polling/SelectSet/StoragePodSelectSet.php b/library/Vspheredb/Polling/SelectSet/StoragePodSelectSet.php
index f5854ce1..90349bdc 100644
--- a/library/Vspheredb/Polling/SelectSet/StoragePodSelectSet.php
+++ b/library/Vspheredb/Polling/SelectSet/StoragePodSelectSet.php
@@ -4,13 +4,13 @@
 
 class StoragePodSelectSet implements SelectSet
 {
-    public static function create()
+    public static function create(): array
     {
         return [
             GenericSpec::traverseFolder([
-                GenericSpec::TRAVERSE_DC_DATA_STORES,
+                GenericSpec::TRAVERSE_DC_DATA_STORES
             ]),
-            GenericSpec::traverseDatacenterDataStores(),
+            GenericSpec::traverseDatacenterDataStores()
         ];
     }
 }
diff --git a/library/Vspheredb/Polling/SelectSet/VirtualMachineSelectSet.php b/library/Vspheredb/Polling/SelectSet/VirtualMachineSelectSet.php
index e05b3bd6..6c04c46d 100644
--- a/library/Vspheredb/Polling/SelectSet/VirtualMachineSelectSet.php
+++ b/library/Vspheredb/Polling/SelectSet/VirtualMachineSelectSet.php
@@ -6,15 +6,15 @@ class VirtualMachineSelectSet implements SelectSet
 {
     public const TRAVERSE_VIRTUAL_APP = 'TraverseVirtualApp';
 
-    public static function create()
+    public static function create(): array
     {
         return [
             GenericSpec::traverseFolder([
                 self::TRAVERSE_VIRTUAL_APP,
-                GenericSpec::TRAVERSE_DC_VIRTUAL_MACHINES,
+                GenericSpec::TRAVERSE_DC_VIRTUAL_MACHINES
             ]),
             GenericSpec::traverseDatacenterVirtualMachines(),
-            GenericSpec::traverse(self::TRAVERSE_VIRTUAL_APP, 'VirtualApp', 'vm'),
+            GenericSpec::traverse(self::TRAVERSE_VIRTUAL_APP, 'VirtualApp', 'vm')
         ];
     }
 }
diff --git a/library/Vspheredb/Polling/ServerInfo.php b/library/Vspheredb/Polling/ServerInfo.php
index f438829f..24d284b7 100644
--- a/library/Vspheredb/Polling/ServerInfo.php
+++ b/library/Vspheredb/Polling/ServerInfo.php
@@ -6,16 +6,17 @@
 use gipfl\Json\JsonString;
 use Icinga\Module\Vspheredb\DbObject\VCenterServer;
 use InvalidArgumentException;
+use stdClass;
 
 use function array_key_exists;
 
 class ServerInfo implements JsonSerialization
 {
-    /** @var array */
-    protected $properties;
+    protected array $properties;
 
     /**
      * ServerInfo constructor.
+     *
      * @param array $properties
      */
     public function __construct(array $properties)
@@ -45,6 +46,7 @@ public static function fromSerialization($object): ServerInfo
 
     /**
      * @param VCenterServer $server
+     *
      * @return static
      */
     public static function fromServer(VCenterServer $server): ServerInfo
@@ -61,28 +63,25 @@ public function isEnabled(): bool
      * @param string $key
      * @param null $default
      *
-     * @return mixed|null
+     * @return ?mixed
      */
     public function get(string $key, $default = null): mixed
     {
         if (array_key_exists($key, $this->properties)) {
-            if ($this->properties[$key] === null) {
-                return $default;
-            } else {
-                return $this->properties[$key];
-            }
+            return $this->properties[$key] === null ? $default : $this->properties[$key];
         }
 
         throw new InvalidArgumentException("Trying to access invalid property: '$key'");
     }
 
-    public function jsonSerialize(): \stdClass
+    public function jsonSerialize(): stdClass
     {
         ksort($this->properties);
+
         return (object) $this->properties;
     }
 
-    public function getUrl()
+    public function getUrl(): string
     {
         return sprintf(
             '%s://%s',
diff --git a/library/Vspheredb/Polling/ServerSet.php b/library/Vspheredb/Polling/ServerSet.php
index 1fd23efa..3cd3084d 100644
--- a/library/Vspheredb/Polling/ServerSet.php
+++ b/library/Vspheredb/Polling/ServerSet.php
@@ -8,7 +8,7 @@
 class ServerSet implements JsonSerialization
 {
     /** @var array<int, ServerInfo> */
-    protected $servers = [];
+    protected array $servers = [];
 
     /**
      * ServerSet constructor.
@@ -37,7 +37,7 @@ public function listServerIds(): array
         return array_keys($this->servers);
     }
 
-    public function addServer(ServerInfo $server)
+    public function addServer(ServerInfo $server): void
     {
         $this->servers[$server->getServerId()] = $server;
         ksort($this->servers);
@@ -58,6 +58,7 @@ public function getServers(): array
 
     /**
      * @param VCenterServer[] $servers
+     *
      * @return static
      */
     public static function fromServers(array $servers): ServerSet
diff --git a/library/Vspheredb/Polling/SyncStore/HostHardwareSyncStore.php b/library/Vspheredb/Polling/SyncStore/HostHardwareSyncStore.php
index f50e85f9..a3debeed 100644
--- a/library/Vspheredb/Polling/SyncStore/HostHardwareSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/HostHardwareSyncStore.php
@@ -4,8 +4,11 @@
 
 class HostHardwareSyncStore extends HostPropertyInstancesSyncStore
 {
-    protected $baseKey = 'hardware.pciDevice';
-    protected $keyProperty = 'id';
-    protected $dbKeyProperty = 'id';
-    protected $instanceClass = 'HostPciDevice';
+    protected string $baseKey = 'hardware.pciDevice';
+
+    protected string $keyProperty = 'id';
+
+    protected string $dbKeyProperty = 'id';
+
+    protected string $instanceClass = 'HostPciDevice';
 }
diff --git a/library/Vspheredb/Polling/SyncStore/HostHbaSyncStore.php b/library/Vspheredb/Polling/SyncStore/HostHbaSyncStore.php
index 023dbf48..f3a92e13 100644
--- a/library/Vspheredb/Polling/SyncStore/HostHbaSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/HostHbaSyncStore.php
@@ -4,8 +4,11 @@
 
 class HostHbaSyncStore extends HostPropertyInstancesSyncStore
 {
-    protected $baseKey = 'config.storageDevice.hostBusAdapter';
-    protected $keyProperty = 'key';
-    protected $dbKeyProperty = 'hba_key';
-    protected $instanceClass = 'HostHostBusAdapter';
+    protected string $baseKey = 'config.storageDevice.hostBusAdapter';
+
+    protected string $keyProperty = 'key';
+
+    protected string $dbKeyProperty = 'hba_key';
+
+    protected string $instanceClass = 'HostHostBusAdapter';
 }
diff --git a/library/Vspheredb/Polling/SyncStore/HostPhysicalNicSyncStore.php b/library/Vspheredb/Polling/SyncStore/HostPhysicalNicSyncStore.php
index 4b00a75e..4c07139e 100644
--- a/library/Vspheredb/Polling/SyncStore/HostPhysicalNicSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/HostPhysicalNicSyncStore.php
@@ -4,8 +4,11 @@
 
 class HostPhysicalNicSyncStore extends HostPropertyInstancesSyncStore
 {
-    protected $baseKey = 'config.network.pnic';
-    protected $keyProperty = 'key';
-    protected $dbKeyProperty = 'nic_key';
-    protected $instanceClass = 'PhysicalNic';
+    protected string $baseKey = 'config.network.pnic';
+
+    protected string $keyProperty = 'key';
+
+    protected string $dbKeyProperty = 'nic_key';
+
+    protected string $instanceClass = 'PhysicalNic';
 }
diff --git a/library/Vspheredb/Polling/SyncStore/HostPropertyInstancesSyncStore.php b/library/Vspheredb/Polling/SyncStore/HostPropertyInstancesSyncStore.php
index 3ffb1c46..05bda1d4 100644
--- a/library/Vspheredb/Polling/SyncStore/HostPropertyInstancesSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/HostPropertyInstancesSyncStore.php
@@ -10,19 +10,21 @@ abstract class HostPropertyInstancesSyncStore extends SyncStore
 {
     use SyncHelper;
 
-    protected $baseKey = 'undefined.property';
-    protected $keyProperty = 'undefinedKeyProperty';
-    protected $dbKeyProperty = 'undefinedKeyProperty';
-    protected $instanceClass = 'undefinedInstanceClass';
+    protected string $baseKey = 'undefined.property';
 
-    public function store($result, $class, SyncStats $stats)
+    protected string $keyProperty = 'undefinedKeyProperty';
+
+    protected string $dbKeyProperty = 'undefinedKeyProperty';
+
+    protected string $instanceClass = 'undefinedInstanceClass';
+
+    public function store($result, $class, SyncStats $stats): void
     {
         $connection = $this->vCenter->getConnection();
         $dbObjects = $class::loadAllForVCenter($this->vCenter);
 
         $baseKey = $this->baseKey;
         $keyProperty = $this->keyProperty;
-        /** @var string $dbKeyProperty */
         $dbKeyProperty = $this->dbKeyProperty;
         $instanceClass = $this->instanceClass;
 
@@ -30,13 +32,9 @@ public function store($result, $class, SyncStats $stats)
         foreach ($result as $object) {
             $object = (object) $object;
             // Hint: this is now dealt with by makeBinaryGlobalMoRefUuid()
-            if ($object->obj instanceof ManagedObjectReference) {
-                $uuid = $this->vCenter->makeBinaryGlobalMoRefUuid($object->obj);
-            } else {
-                $uuid = $this->vCenter->makeBinaryGlobalMoRefUuid(
-                    ManagedObjectReference::fromSerialization($object->obj)
-                );
-            }
+            $uuid = $object->obj instanceof ManagedObjectReference
+                ? $this->vCenter->makeBinaryGlobalMoRefUuid($object->obj)
+                : $this->vCenter->makeBinaryGlobalMoRefUuid(ManagedObjectReference::fromSerialization($object->obj));
             if (! isset($object->$baseKey) || ! property_exists($object->$baseKey, $instanceClass)) {
                 // No instance information for this host
                 continue;
diff --git a/library/Vspheredb/Polling/SyncStore/HostSensorSyncStore.php b/library/Vspheredb/Polling/SyncStore/HostSensorSyncStore.php
index 6343b5ae..c16312c9 100644
--- a/library/Vspheredb/Polling/SyncStore/HostSensorSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/HostSensorSyncStore.php
@@ -4,8 +4,11 @@
 
 class HostSensorSyncStore extends HostPropertyInstancesSyncStore
 {
-    protected $baseKey = 'runtime.healthSystemRuntime.systemHealthInfo.numericSensorInfo';
-    protected $keyProperty = 'name';
-    protected $dbKeyProperty = 'name';
-    protected $instanceClass = 'HostNumericSensorInfo';
+    protected string $baseKey = 'runtime.healthSystemRuntime.systemHealthInfo.numericSensorInfo';
+
+    protected string $keyProperty = 'name';
+
+    protected string $dbKeyProperty = 'name';
+
+    protected string $instanceClass = 'HostNumericSensorInfo';
 }
diff --git a/library/Vspheredb/Polling/SyncStore/HostVirtualNicSyncStore.php b/library/Vspheredb/Polling/SyncStore/HostVirtualNicSyncStore.php
index 0ee8cfb9..967333b9 100644
--- a/library/Vspheredb/Polling/SyncStore/HostVirtualNicSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/HostVirtualNicSyncStore.php
@@ -4,8 +4,11 @@
 
 class HostVirtualNicSyncStore extends HostPropertyInstancesSyncStore
 {
-    protected $baseKey = 'config.network.vnic';
-    protected $keyProperty = 'key';
-    protected $dbKeyProperty = 'nic_key';
-    protected $instanceClass = 'HostVirtualNic';
+    protected string $baseKey = 'config.network.vnic';
+
+    protected string $keyProperty = 'key';
+
+    protected string $dbKeyProperty = 'nic_key';
+
+    protected string $instanceClass = 'HostVirtualNic';
 }
diff --git a/library/Vspheredb/Polling/SyncStore/ManagedObjectReferenceSyncStore.php b/library/Vspheredb/Polling/SyncStore/ManagedObjectReferenceSyncStore.php
index 91e39934..69901428 100644
--- a/library/Vspheredb/Polling/SyncStore/ManagedObjectReferenceSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/ManagedObjectReferenceSyncStore.php
@@ -13,7 +13,7 @@ class ManagedObjectReferenceSyncStore extends SyncStore
 {
     use SyncHelper;
 
-    public function store($result, $class, SyncStats $stats)
+    public function store($result, $class, SyncStats $stats): void
     {
         $connection = $this->vCenter->getConnection();
         $vCenter = $this->vCenter;
@@ -47,6 +47,7 @@ public function store($result, $class, SyncStats $stats)
                     $fetched[$uuid],
                     Uuid::fromBytes($uuid)->toString()
                 ));
+
                 return;
             }
             $fetched[$uuid] = $name;
@@ -67,7 +68,7 @@ public function store($result, $class, SyncStats $stats)
                     'object_name'    => $name,
                     'object_type'    => $moRef->type,
                     'overall_status' => $obj->overallStatus,
-                    'tags'           => JsonString::encode($tags),
+                    'tags'           => JsonString::encode($tags)
                 ], $connection);
             }
             if (property_exists($obj, 'parent')) {
@@ -78,23 +79,18 @@ public function store($result, $class, SyncStats $stats)
         }
 
         if (! empty($vmUuidsWithNoParent)) {
-            $this->logger->debug(\sprintf(
+            $this->logger->debug(sprintf(
                 'There are %d VMs without parent',
-                \count($vmUuidsWithNoParent)
+                count($vmUuidsWithNoParent)
             ));
         }
 
         /** @var string $parentName */
         foreach ($idToParent as $uuid => $parentName) {
             if (array_key_exists($parentName, $nameUuids)) {
-                $objects[$uuid]->setParent(
-                    $objects[$nameUuids[$parentName]]
-                );
+                $objects[$uuid]->setParent($objects[$nameUuids[$parentName]]);
             } else {
-                $this->logger->error(sprintf(
-                    "Could not find parent $parentName for %s",
-                    $fetched[$uuid]
-                ));
+                $this->logger->error(sprintf("Could not find parent $parentName for %s", $fetched[$uuid]));
             }
         }
 
diff --git a/library/Vspheredb/Polling/SyncStore/ObjectSyncStore.php b/library/Vspheredb/Polling/SyncStore/ObjectSyncStore.php
index 5244cc1e..a607fca6 100644
--- a/library/Vspheredb/Polling/SyncStore/ObjectSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/ObjectSyncStore.php
@@ -15,8 +15,7 @@ class ObjectSyncStore extends SyncStore
 
     public const CUSTOM_VALUE_KEY = 'summary.customValue';
 
-    /** @var ?array */
-    protected $customFieldsMap;
+    protected ?array $customFieldsMap;
 
     public function __construct(
         $db,
@@ -28,7 +27,7 @@ public function __construct(
         parent::__construct($db, $vCenter, $logger);
     }
 
-    protected function indexByUuid($result)
+    protected function indexByUuid($result): array
     {
         // map by key
         $fromApi = [];
@@ -50,7 +49,7 @@ protected function indexByUuid($result)
         return $fromApi;
     }
 
-    public function store($result, $class, SyncStats $stats)
+    public function store($result, $class, SyncStats $stats): void
     {
         $result = $this->indexByUuid($result);
         $dbObjects = $class::loadAllForVCenter($this->vCenter);
@@ -72,7 +71,7 @@ public function store($result, $class, SyncStats $stats)
         $this->storeSyncObjects($connection->getDbAdapter(), $dbObjects, $result, $stats);
     }
 
-    protected static function mapResultCustomValues($object, array $map)
+    protected static function mapResultCustomValues($object, array $map): void
     {
         $key = self::CUSTOM_VALUE_KEY;
         if (isset($object->$key) && ! empty((array) $object->$key)) {
diff --git a/library/Vspheredb/Polling/SyncStore/PerfCounterInfoSyncStore.php b/library/Vspheredb/Polling/SyncStore/PerfCounterInfoSyncStore.php
index 9fbaae3d..86b1b885 100644
--- a/library/Vspheredb/Polling/SyncStore/PerfCounterInfoSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/PerfCounterInfoSyncStore.php
@@ -14,7 +14,7 @@ class PerfCounterInfoSyncStore extends SyncStore
 {
     use SyncHelper;
 
-    public function store($result, $class, SyncStats $stats)
+    public function store($result, $class, SyncStats $stats): void
     {
         if (! $result instanceof PerformanceManager) {
             throw new InvalidArgumentException('PerformanceManager expected, got: ' . var_export($result, 1));
@@ -27,9 +27,13 @@ public function store($result, $class, SyncStats $stats)
      * TODO: really sync
      *
      * @param PerfCounterInfo[] $infos
+     * @param SyncStats $stats
+     *
+     * @return void
+     *
      * @throws Exception
      */
-    protected function processCounterInfo(array $infos, SyncStats $stats)
+    protected function processCounterInfo(array $infos, SyncStats $stats): void
     {
         $uuid = $this->vCenter->get('uuid');
         $db = $this->vCenter->getDb();
@@ -47,7 +51,7 @@ protected function processCounterInfo(array $infos, SyncStats $stats)
                     'vcenter_uuid' => $uuid,
                     'name'    => $group,
                     'label'   => $info->groupInfo->label,
-                    'summary' => $info->groupInfo->summary,
+                    'summary' => $info->groupInfo->summary
                 ];
             }
             if (! array_key_exists($unit, $units)) {
@@ -55,7 +59,7 @@ protected function processCounterInfo(array $infos, SyncStats $stats)
                     'vcenter_uuid' => $uuid,
                     'name'    => $unit,
                     'label'   => $info->unitInfo->label,
-                    'summary' => $info->unitInfo->summary,
+                    'summary' => $info->unitInfo->summary
                 ];
             }
             $counter = [
@@ -66,10 +70,10 @@ protected function processCounterInfo(array $infos, SyncStats $stats)
                 'unit_name'        => $unit,
                 'label'            => $info->nameInfo->label,
                 'summary'          => $info->nameInfo->summary,
-                'rollup_type'      => (string) $info->rollupType,
-                'stats_type'       => (string) $info->statsType,
+                'rollup_type'      => $info->rollupType,
+                'stats_type'       => $info->statsType,
                 'level'            => $info->level ?? 0, // ESXi? Check docs!
-                'per_device_level' => $info->perDeviceLevel ?? 0,
+                'per_device_level' => $info->perDeviceLevel ?? 0
             ];
             $counters[] = $counter;
         }
diff --git a/library/Vspheredb/Polling/SyncStore/SyncStore.php b/library/Vspheredb/Polling/SyncStore/SyncStore.php
index c9a3bfdc..402537ac 100644
--- a/library/Vspheredb/Polling/SyncStore/SyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/SyncStore.php
@@ -2,33 +2,30 @@
 
 namespace Icinga\Module\Vspheredb\Polling\SyncStore;
 
-use gipfl\ZfDb\Adapter\Adapter;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Module\Vspheredb\SyncRelated\SyncStats;
 use Psr\Log\LoggerInterface;
+use Zend_Db_Adapter_Abstract;
 
 abstract class SyncStore
 {
-    /** @var Adapter|\Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
     /**
-     * @param Adapter|\Zend_Db_Adapter_Abstract $db
+     * @param Zend_Db_Adapter_Abstract $db
      * @param VCenter $vCenter
      * @param LoggerInterface $logger
      */
-    public function __construct($db, VCenter $vCenter, LoggerInterface $logger)
+    public function __construct(Zend_Db_Adapter_Abstract $db, VCenter $vCenter, LoggerInterface $logger)
     {
         $this->db = $db;
         $this->vCenter = $vCenter;
         $this->logger = $logger;
     }
 
-    abstract public function store($result, $class, SyncStats $stats);
+    abstract public function store($result, $class, SyncStats $stats): void;
 }
diff --git a/library/Vspheredb/Polling/SyncStore/TaggingSyncStore.php b/library/Vspheredb/Polling/SyncStore/TaggingSyncStore.php
index 63140ba0..a45f899f 100644
--- a/library/Vspheredb/Polling/SyncStore/TaggingSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/TaggingSyncStore.php
@@ -10,7 +10,7 @@ class TaggingSyncStore extends SyncStore
 {
     use SyncHelper;
 
-    public function store($result, $class, SyncStats $stats)
+    public function store($result, $class, SyncStats $stats): void
     {
         $result = self::wantBinaryUuids($result);
         $dbObjects = $class::loadAllForVCenter($this->vCenter);
@@ -21,9 +21,7 @@ public function store($result, $class, SyncStats $stats)
             if (array_key_exists($idx, $dbObjects)) {
                 $dbObject = $dbObjects[$idx];
             } else {
-                $dbObjects[$idx] = $dbObject = $class::create([
-                    'vcenter_uuid' => $vCenterUuid
-                ], $connection);
+                $dbObjects[$idx] = $dbObject = $class::create(['vcenter_uuid' => $vCenterUuid], $connection);
             }
             $dbObject->setMapped($object, $this->vCenter);
         }
diff --git a/library/Vspheredb/Polling/SyncStore/VmDatastoreUsageSyncStore.php b/library/Vspheredb/Polling/SyncStore/VmDatastoreUsageSyncStore.php
index cc7ad2d2..9695d7c6 100644
--- a/library/Vspheredb/Polling/SyncStore/VmDatastoreUsageSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/VmDatastoreUsageSyncStore.php
@@ -10,6 +10,8 @@
 use Icinga\Module\Vspheredb\Util;
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
 use Psr\Log\LoggerInterface;
+use React\Promise\PromiseInterface;
+use Zend_Db_Adapter_Abstract;
 
 use function React\Promise\all;
 use function React\Promise\resolve;
@@ -20,7 +22,7 @@ class VmDatastoreUsageSyncStore extends SyncStore
 
     // Refresh outdated VMs -> before and after?
 
-    public function store($result, $class, SyncStats $stats)
+    public function store($result, $class, SyncStats $stats): void
     {
         $vCenter = $this->vCenter;
         $vCenterUuid = $vCenter->getUuid();
@@ -35,11 +37,9 @@ public function store($result, $class, SyncStats $stats)
             if (! isset($map->{'storage.perDatastoreUsage'}->{'VirtualMachineUsageOnDatastore'})) {
                 continue;
             }
-            if (isset($map->{'storage.timestamp'})) {
-                $timestamp = Util::timeStringToUnixMs($map->{'storage.timestamp'});
-            } else {
-                $timestamp = null;
-            }
+            $timestamp = isset($map->{'storage.timestamp'})
+                ? Util::timeStringToUnixMs($map->{'storage.timestamp'})
+                : null;
             foreach ($map->{'storage.perDatastoreUsage'}->{'VirtualMachineUsageOnDatastore'} as $usage) {
                 $dsUuid = $vCenter->makeBinaryGlobalMoRefUuid($usage->datastore);
                 $key = "$vmUuid$dsUuid";
@@ -47,7 +47,7 @@ public function store($result, $class, SyncStats $stats)
                     'committed'   => $usage->committed,
                     'uncommitted' => $usage->uncommitted,
                     'unshared'    => $usage->unshared,
-                    'ts_updated'  => $timestamp,
+                    'ts_updated'  => $timestamp
                 ];
                 $seen[$key] = $key;
                 if (array_key_exists($key, $dbObjects)) {
@@ -65,7 +65,7 @@ public function store($result, $class, SyncStats $stats)
         $this->storeSyncObjects($connection->getDbAdapter(), $dbObjects, $seen, $stats);
     }
 
-    public static function fetchOutdatedVms(VCenter $vCenter, $lastRefreshSecondsAgo = 1800, $cntMax = null)
+    public static function fetchOutdatedVms(VCenter $vCenter, $lastRefreshSecondsAgo = 1800, $cntMax = null): array
     {
         $db = $vCenter->getDb();
         $vCenterUuid = $vCenter->get('uuid');
@@ -75,7 +75,7 @@ public static function fetchOutdatedVms(VCenter $vCenter, $lastRefreshSecondsAgo
 
         $query = $db->select()->from(['o' => 'object'], [
             'moref'       => 'o.moref',
-            'object_name' => 'o.object_name',
+            'object_name' => 'o.object_name'
         ])->join(
             ['vm' => 'virtual_machine'],
             "vm.uuid = o.uuid AND vm.template = 'n' AND vm.runtime_power_state = 'poweredOn'",
@@ -98,7 +98,7 @@ public static function fetchOutdatedVms(VCenter $vCenter, $lastRefreshSecondsAgo
         return $db->fetchPairs($query);
     }
 
-    public static function refreshOutdatedVms(VsphereApi $api, $vms, LoggerInterface $logger)
+    public static function refreshOutdatedVms(VsphereApi $api, $vms, LoggerInterface $logger): PromiseInterface
     {
         if (empty($vms)) {
             return resolve(null);
@@ -117,7 +117,7 @@ public static function refreshOutdatedVms(VsphereApi $api, $vms, LoggerInterface
         return all($pending);
     }
 
-    protected function makeWhere(\Zend_Db_Adapter_Abstract $db, $vmUuid, $dsUuid)
+    protected function makeWhere(Zend_Db_Adapter_Abstract $db, $vmUuid, $dsUuid): string
     {
         return $db->quoteInto('vm_uuid = ?', $vmUuid)
             . $db->quoteInto(' AND datastore_uuid = ?', $dsUuid);
diff --git a/library/Vspheredb/Polling/SyncStore/VmDiskUsageSyncStore.php b/library/Vspheredb/Polling/SyncStore/VmDiskUsageSyncStore.php
index 34e0adbe..cee10c05 100644
--- a/library/Vspheredb/Polling/SyncStore/VmDiskUsageSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/VmDiskUsageSyncStore.php
@@ -5,12 +5,13 @@
 use Icinga\Module\Vspheredb\SyncRelated\SyncHelper;
 use Icinga\Module\Vspheredb\SyncRelated\SyncStats;
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
+use stdClass;
 
 class VmDiskUsageSyncStore extends SyncStore
 {
     use SyncHelper;
 
-    public function store($result, $class, SyncStats $stats)
+    public function store($result, $class, SyncStats $stats): void
     {
         $vCenter = $this->vCenter;
         $vCenterUuid = $vCenter->getUuid();
@@ -22,11 +23,9 @@ public function store($result, $class, SyncStats $stats)
         $skipUuids = [];
         foreach ($result as $object) {
             $object = (object) $object;
-            if ($object->obj instanceof ManagedObjectReference) {
-                $uuid = $vCenter->makeBinaryGlobalMoRefUuid($object->obj);
-            } else {
-                $uuid = $vCenter->makeBinaryGlobalMoRefUuid(ManagedObjectReference::fromSerialization($object->obj));
-            }
+            $uuid = $object->obj instanceof ManagedObjectReference
+                ? $vCenter->makeBinaryGlobalMoRefUuid($object->obj)
+                : $vCenter->makeBinaryGlobalMoRefUuid(ManagedObjectReference::fromSerialization($object->obj));
             if (! property_exists($object->{'guest.disk'}, 'GuestDiskInfo')) {
                 $skipUuids[] = $uuid;
                 // Preserve former disks. Should we flag them as outdated?
@@ -47,17 +46,10 @@ public function store($result, $class, SyncStats $stats)
                 } elseif ($path === '/var') {
                     $var = $info;
                 } elseif (is_object($root) && in_array($path, ['/tmp', '/var/tmp'])) {
-                    if ($path === '/var/tmp' && is_object($var)) {
-                        $base = $var;
-                    } else {
-                        $base = $root;
-                    }
+                    $base = $path === '/var/tmp' && is_object($var) ? $var : $root;
 
-                    /** @var \stdClass $base */
-                    if (
-                        $info->capacity === $base->capacity
-                        && $info->freeSpace === $base->freeSpace
-                    ) {
+                    /** @var stdClass $base */
+                    if ($info->capacity === $base->capacity && $info->freeSpace === $base->freeSpace) {
                         continue;
                     }
                 }
@@ -90,7 +82,7 @@ public function store($result, $class, SyncStats $stats)
                         'vcenter_uuid' => $vCenterUuid,
                         'disk_path'    => $path,
                         'capacity'     => $info->capacity,
-                        'free_space'   => $info->freeSpace,
+                        'free_space'   => $info->freeSpace
                     ], $connection);
                 }
             }
diff --git a/library/Vspheredb/Polling/SyncStore/VmEventHistorySyncStore.php b/library/Vspheredb/Polling/SyncStore/VmEventHistorySyncStore.php
index 47285d2a..3fc2dd4c 100644
--- a/library/Vspheredb/Polling/SyncStore/VmEventHistorySyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/VmEventHistorySyncStore.php
@@ -2,20 +2,24 @@
 
 namespace Icinga\Module\Vspheredb\Polling\SyncStore;
 
+use gipfl\ZfDb\Exception\SelectException;
 use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\MappedClass\KnownEvent;
 use Icinga\Module\Vspheredb\SyncRelated\SyncHelper;
 use Icinga\Module\Vspheredb\SyncRelated\SyncStats;
 use RuntimeException;
+use Zend_Db_Adapter_Abstract;
+use Zend_Db_Select_Exception;
 
 class VmEventHistorySyncStore extends SyncStore
 {
     use SyncHelper;
 
-    protected $lastEventKey;
-    protected $lastEventTimestamp;
+    protected ?int $lastEventKey = null;
 
-    public function store($result, $class, SyncStats $stats)
+    protected ?int $lastEventTimestamp = null;
+
+    public function store($result, $class, SyncStats $stats): void
     {
         if (empty($result)) {
             return;
@@ -25,7 +29,7 @@ public function store($result, $class, SyncStats $stats)
             $this->lastEventKey = $this->getLastEventKey();
             $this->lastEventTimestamp = $this->getLastEventTimeStamp();
             $stats->setFromApi(count($result));
-            foreach ($result as $key => $event) {
+            foreach ($result as $event) {
                 if (! isset($event->__class)) {
                     $this->logger->error(json_encode($event));
                     return;
@@ -70,31 +74,34 @@ public function store($result, $class, SyncStats $stats)
 
     /**
      * @return int
-     * @throws \Zend_Db_Select_Exception
-     * @throws \gipfl\ZfDb\Exception\SelectException
+     *
+     * @throws Zend_Db_Select_Exception
+     * @throws SelectException
      */
-    protected function getLastEventKey()
+    protected function getLastEventKey(): int
     {
         return static::selectLast($this->db, $this->vCenter->getUuid(), 'event_key');
     }
 
     /**
      * @return int
-     * @throws \Zend_Db_Select_Exception
-     * @throws \gipfl\ZfDb\Exception\SelectException
+     *
+     * @throws Zend_Db_Select_Exception
+     * @throws SelectException
      */
-    public function getLastEventTimeStamp()
+    public function getLastEventTimeStamp(): int
     {
         return static::selectLast($this->db, $this->vCenter->getUuid(), 'ts_event_ms');
     }
 
     /**
-     * @param $db
+     * @param Zend_Db_Adapter_Abstract $db
      * @param string $vCenterUuid
      * @param string $column
+     *
      * @return int
      */
-    public static function selectLast($db, $vCenterUuid, $column)
+    public static function selectLast(Zend_Db_Adapter_Abstract $db, $vCenterUuid, string $column): int
     {
         $union = $db->select()->union([
             'vmeh' => $db->select()->from(
@@ -104,7 +111,7 @@ public static function selectLast($db, $vCenterUuid, $column)
             'ah' => $db->select()->from(
                 'alarm_history',
                 [$column => "MAX($column)"]
-            )->where('vcenter_uuid = ?', $vCenterUuid),
+            )->where('vcenter_uuid = ?', $vCenterUuid)
         ], Select::SQL_UNION_ALL);
 
         return (int) $db->fetchOne(
diff --git a/library/Vspheredb/Polling/SyncStore/VmHardwareSyncStore.php b/library/Vspheredb/Polling/SyncStore/VmHardwareSyncStore.php
index c214792f..4026eeac 100644
--- a/library/Vspheredb/Polling/SyncStore/VmHardwareSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/VmHardwareSyncStore.php
@@ -13,7 +13,7 @@ class VmHardwareSyncStore extends SyncStore
 {
     use SyncHelper;
 
-    public function store($result, $class, SyncStats $stats)
+    public function store($result, $class, SyncStats $stats): void
     {
         $vCenter = $this->vCenter;
         $connection = $vCenter->getConnection();
@@ -83,13 +83,10 @@ public function store($result, $class, SyncStats $stats)
         $this->storeSyncObjects($connection->getDbAdapter(), $nics, $seen, $ignoreNicStats);
     }
 
-    protected function assertValidDeviceKey($device)
+    protected function assertValidDeviceKey($device): void
     {
         if (! is_int($device->key)) {
-            throw new InvalidArgumentException(
-                'Got invalid device key "%s", integer expected',
-                $device->key
-            );
+            throw new InvalidArgumentException('Got invalid device key "%s", integer expected', $device->key);
         }
     }
 }
diff --git a/library/Vspheredb/Polling/SyncStore/VmSnapshotSyncStore.php b/library/Vspheredb/Polling/SyncStore/VmSnapshotSyncStore.php
index ca3bc196..ce96651f 100644
--- a/library/Vspheredb/Polling/SyncStore/VmSnapshotSyncStore.php
+++ b/library/Vspheredb/Polling/SyncStore/VmSnapshotSyncStore.php
@@ -10,7 +10,7 @@ class VmSnapshotSyncStore extends SyncStore
 {
     use SyncHelper;
 
-    public function store($result, $class, SyncStats $stats)
+    public function store($result, $class, SyncStats $stats): void
     {
         $vCenter = $this->vCenter;
         $vCenterUuid = $vCenter->getUuid();
diff --git a/library/Vspheredb/Polling/SyncTask/ComputeResourceSyncTask.php b/library/Vspheredb/Polling/SyncTask/ComputeResourceSyncTask.php
index 4a1fd694..d7b2ae6c 100644
--- a/library/Vspheredb/Polling/SyncTask/ComputeResourceSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/ComputeResourceSyncTask.php
@@ -9,10 +9,15 @@
 
 class ComputeResourceSyncTask extends SyncTask
 {
-    protected $label = 'Compute Resources';
-    protected $tableName = 'compute_resource';
-    protected $objectClass = ComputeResource::class;
-    protected $selectSetClass = ComputeResourceSelectSet::class;
-    protected $propertySetClass = ComputeResourcePropertySet::class;
-    protected $syncStoreClass = ObjectSyncStore::class;
+    protected string $label = 'Compute Resources';
+
+    protected string $tableName = 'compute_resource';
+
+    protected string $objectClass = ComputeResource::class;
+
+    protected string $selectSetClass = ComputeResourceSelectSet::class;
+
+    protected string $propertySetClass = ComputeResourcePropertySet::class;
+
+    protected string $syncStoreClass = ObjectSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/DatastoreSyncTask.php b/library/Vspheredb/Polling/SyncTask/DatastoreSyncTask.php
index ec467349..caf38e4a 100644
--- a/library/Vspheredb/Polling/SyncTask/DatastoreSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/DatastoreSyncTask.php
@@ -9,10 +9,15 @@
 
 class DatastoreSyncTask extends SyncTask
 {
-    protected $label = 'Data Stores';
-    protected $tableName = 'datastore';
-    protected $objectClass = Datastore::class;
-    protected $selectSetClass = DatastoreSelectSet::class;
-    protected $propertySetClass = DatastorePropertySet::class;
-    protected $syncStoreClass = ObjectSyncStore::class;
+    protected string $label = 'Data Stores';
+
+    protected string $tableName = 'datastore';
+
+    protected string $objectClass = Datastore::class;
+
+    protected string $selectSetClass = DatastoreSelectSet::class;
+
+    protected string $propertySetClass = DatastorePropertySet::class;
+
+    protected string $syncStoreClass = ObjectSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/HostHardwareSyncTask.php b/library/Vspheredb/Polling/SyncTask/HostHardwareSyncTask.php
index ad64a5f0..b70db8ed 100644
--- a/library/Vspheredb/Polling/SyncTask/HostHardwareSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/HostHardwareSyncTask.php
@@ -9,10 +9,15 @@
 
 class HostHardwareSyncTask extends SyncTask
 {
-    protected $label = 'Host Hardware';
-    protected $tableName = 'host_pci_device';
-    protected $objectClass = HostPciDevice::class;
-    protected $selectSetClass = HostSystemSelectSet::class;
-    protected $propertySetClass = HostHardwarePropertySet::class;
-    protected $syncStoreClass = HostHardwareSyncStore::class;
+    protected string $label = 'Host Hardware';
+
+    protected string $tableName = 'host_pci_device';
+
+    protected string $objectClass = HostPciDevice::class;
+
+    protected string $selectSetClass = HostSystemSelectSet::class;
+
+    protected string $propertySetClass = HostHardwarePropertySet::class;
+
+    protected string $syncStoreClass = HostHardwareSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/HostHbaSyncTask.php b/library/Vspheredb/Polling/SyncTask/HostHbaSyncTask.php
index 50b6f586..22c8955c 100644
--- a/library/Vspheredb/Polling/SyncTask/HostHbaSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/HostHbaSyncTask.php
@@ -9,10 +9,15 @@
 
 class HostHbaSyncTask extends SyncTask
 {
-    protected $label = 'Host HBAs';
-    protected $tableName = 'host_hba';
-    protected $objectClass = HostHba::class;
-    protected $selectSetClass = HostSystemSelectSet::class;
-    protected $propertySetClass = HostHbaPropertySet::class;
-    protected $syncStoreClass = HostHbaSyncStore::class;
+    protected string $label = 'Host HBAs';
+
+    protected string $tableName = 'host_hba';
+
+    protected string $objectClass = HostHba::class;
+
+    protected string $selectSetClass = HostSystemSelectSet::class;
+
+    protected string $propertySetClass = HostHbaPropertySet::class;
+
+    protected string $syncStoreClass = HostHbaSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/HostPhysicalNicSyncTask.php b/library/Vspheredb/Polling/SyncTask/HostPhysicalNicSyncTask.php
index ec414e19..59e063f8 100644
--- a/library/Vspheredb/Polling/SyncTask/HostPhysicalNicSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/HostPhysicalNicSyncTask.php
@@ -9,10 +9,15 @@
 
 class HostPhysicalNicSyncTask extends SyncTask
 {
-    protected $label = 'Host Physical NICs';
-    protected $tableName = 'host_physical_nic';
-    protected $objectClass = HostPhysicalNic::class;
-    protected $selectSetClass = HostSystemSelectSet::class;
-    protected $propertySetClass = HostPhysicalNicPropertySet::class;
-    protected $syncStoreClass = HostPhysicalNicSyncStore::class;
+    protected string $label = 'Host Physical NICs';
+
+    protected string $tableName = 'host_physical_nic';
+
+    protected string $objectClass = HostPhysicalNic::class;
+
+    protected string $selectSetClass = HostSystemSelectSet::class;
+
+    protected string $propertySetClass = HostPhysicalNicPropertySet::class;
+
+    protected string $syncStoreClass = HostPhysicalNicSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/HostQuickStatsSyncTask.php b/library/Vspheredb/Polling/SyncTask/HostQuickStatsSyncTask.php
index 89d7f6ae..7ec40d85 100644
--- a/library/Vspheredb/Polling/SyncTask/HostQuickStatsSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/HostQuickStatsSyncTask.php
@@ -9,10 +9,15 @@
 
 class HostQuickStatsSyncTask extends SyncTask
 {
-    protected $label = 'Host Quick Stats';
-    protected $tableName = 'host_quick_stats';
-    protected $objectClass = HostQuickStats::class;
-    protected $selectSetClass = HostSystemSelectSet::class;
-    protected $propertySetClass = HostQuickStatsPropertySet::class;
-    protected $syncStoreClass = ObjectSyncStore::class;
+    protected string $label = 'Host Quick Stats';
+
+    protected string $tableName = 'host_quick_stats';
+
+    protected string $objectClass = HostQuickStats::class;
+
+    protected string $selectSetClass = HostSystemSelectSet::class;
+
+    protected string $propertySetClass = HostQuickStatsPropertySet::class;
+
+    protected string $syncStoreClass = ObjectSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/HostSensorSyncTask.php b/library/Vspheredb/Polling/SyncTask/HostSensorSyncTask.php
index 1022b0e9..ae43af54 100644
--- a/library/Vspheredb/Polling/SyncTask/HostSensorSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/HostSensorSyncTask.php
@@ -9,10 +9,15 @@
 
 class HostSensorSyncTask extends SyncTask
 {
-    protected $label = 'Host Sensors';
-    protected $tableName = 'host_sensor';
-    protected $objectClass = HostSensor::class;
-    protected $selectSetClass = HostSystemSelectSet::class;
-    protected $propertySetClass = HostSensorsPropertySet::class;
-    protected $syncStoreClass = HostSensorSyncStore::class;
+    protected string $label = 'Host Sensors';
+
+    protected string $tableName = 'host_sensor';
+
+    protected string $objectClass = HostSensor::class;
+
+    protected string $selectSetClass = HostSystemSelectSet::class;
+
+    protected string $propertySetClass = HostSensorsPropertySet::class;
+
+    protected string $syncStoreClass = HostSensorSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/HostSystemSyncTask.php b/library/Vspheredb/Polling/SyncTask/HostSystemSyncTask.php
index 2878f528..0fc59aee 100644
--- a/library/Vspheredb/Polling/SyncTask/HostSystemSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/HostSystemSyncTask.php
@@ -9,10 +9,15 @@
 
 class HostSystemSyncTask extends SyncTask
 {
-    protected $label = 'Host Systems';
-    protected $tableName = 'host_system';
-    protected $objectClass = HostSystem::class;
-    protected $selectSetClass = HostSystemSelectSet::class;
-    protected $propertySetClass = HostSystemPropertySet::class;
-    protected $syncStoreClass = ObjectSyncStore::class;
+    protected string $label = 'Host Systems';
+
+    protected string $tableName = 'host_system';
+
+    protected string $objectClass = HostSystem::class;
+
+    protected string $selectSetClass = HostSystemSelectSet::class;
+
+    protected string $propertySetClass = HostSystemPropertySet::class;
+
+    protected string $syncStoreClass = ObjectSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/HostVirtualNicSyncTask.php b/library/Vspheredb/Polling/SyncTask/HostVirtualNicSyncTask.php
index fb3385dd..4c2d95cf 100644
--- a/library/Vspheredb/Polling/SyncTask/HostVirtualNicSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/HostVirtualNicSyncTask.php
@@ -9,10 +9,15 @@
 
 class HostVirtualNicSyncTask extends SyncTask
 {
-    protected $label = 'Host Virtual NICs';
-    protected $tableName = 'host_virtual_nic';
-    protected $objectClass = HostVirtualNic::class;
-    protected $selectSetClass = HostSystemSelectSet::class;
-    protected $propertySetClass = HostVirtualNicPropertySet::class;
-    protected $syncStoreClass = HostVirtualNicSyncStore::class;
+    protected string $label = 'Host Virtual NICs';
+
+    protected string $tableName = 'host_virtual_nic';
+
+    protected string $objectClass = HostVirtualNic::class;
+
+    protected string $selectSetClass = HostSystemSelectSet::class;
+
+    protected string $propertySetClass = HostVirtualNicPropertySet::class;
+
+    protected string $syncStoreClass = HostVirtualNicSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/ManagedObjectReferenceSyncTask.php b/library/Vspheredb/Polling/SyncTask/ManagedObjectReferenceSyncTask.php
index f4eadd5a..99c71c93 100644
--- a/library/Vspheredb/Polling/SyncTask/ManagedObjectReferenceSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/ManagedObjectReferenceSyncTask.php
@@ -9,10 +9,15 @@
 
 class ManagedObjectReferenceSyncTask extends SyncTask
 {
-    protected $label = 'Managed Object References';
-    protected $tableName = 'object';
-    protected $objectClass = ManagedObject::class;
-    protected $selectSetClass = FullSelectSet::class;
-    protected $propertySetClass = FullObjectListPropertySet::class;
-    protected $syncStoreClass = ManagedObjectReferenceSyncStore::class;
+    protected string $label = 'Managed Object References';
+
+    protected string $tableName = 'object';
+
+    protected string $objectClass = ManagedObject::class;
+
+    protected string $selectSetClass = FullSelectSet::class;
+
+    protected string $propertySetClass = FullObjectListPropertySet::class;
+
+    protected string $syncStoreClass = ManagedObjectReferenceSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/StoragePodSyncTask.php b/library/Vspheredb/Polling/SyncTask/StoragePodSyncTask.php
index 45d82b50..d4343191 100644
--- a/library/Vspheredb/Polling/SyncTask/StoragePodSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/StoragePodSyncTask.php
@@ -9,10 +9,15 @@
 
 class StoragePodSyncTask extends SyncTask
 {
-    protected $label = 'Storage Pods';
-    protected $tableName = 'storage_pod';
-    protected $objectClass = StoragePod::class;
-    protected $selectSetClass = StoragePodSelectSet::class;
-    protected $propertySetClass = StoragePodPropertySet::class;
-    protected $syncStoreClass = ObjectSyncStore::class;
+    protected string $label = 'Storage Pods';
+
+    protected string $tableName = 'storage_pod';
+
+    protected string $objectClass = StoragePod::class;
+
+    protected string $selectSetClass = StoragePodSelectSet::class;
+
+    protected string $propertySetClass = StoragePodPropertySet::class;
+
+    protected string $syncStoreClass = ObjectSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/SyncTask.php b/library/Vspheredb/Polling/SyncTask/SyncTask.php
index 85e691ad..49263835 100644
--- a/library/Vspheredb/Polling/SyncTask/SyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/SyncTask.php
@@ -10,23 +10,17 @@ abstract class SyncTask
 {
     public const UNSPECIFIED = 'unspecified';
 
-    /** @var string */
-    protected $label = self::UNSPECIFIED;
+    protected string $label = self::UNSPECIFIED;
 
-    /** @var string */
-    protected $tableName = self::UNSPECIFIED;
+    protected string $tableName = self::UNSPECIFIED;
 
-    /** @var string */
-    protected $objectClass = self::UNSPECIFIED;
+    protected string $objectClass = self::UNSPECIFIED;
 
-    /** @var string */
-    protected $selectSetClass = self::UNSPECIFIED;
+    protected string $selectSetClass = self::UNSPECIFIED;
 
-    /** @var string */
-    protected $propertySetClass = self::UNSPECIFIED;
+    protected string $propertySetClass = self::UNSPECIFIED;
 
-    /** @var string */
-    protected $syncStoreClass = self::UNSPECIFIED;
+    protected string $syncStoreClass = self::UNSPECIFIED;
 
     public function getLabel(): string
     {
diff --git a/library/Vspheredb/Polling/SyncTask/TaggingCategorySyncTask.php b/library/Vspheredb/Polling/SyncTask/TaggingCategorySyncTask.php
index ed73b8a0..d3eacffc 100644
--- a/library/Vspheredb/Polling/SyncTask/TaggingCategorySyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/TaggingCategorySyncTask.php
@@ -8,9 +8,11 @@
 
 class TaggingCategorySyncTask extends TaggingSyncTask
 {
-    protected $label = 'Tag Categories';
-    protected $tableName = TaggingCategory::TABLE;
-    protected $objectClass = TaggingCategory::class;
+    protected string $label = 'Tag Categories';
+
+    protected string $tableName = TaggingCategory::TABLE;
+
+    protected string $objectClass = TaggingCategory::class;
 
     public function run(RestApi $api): PromiseInterface
     {
diff --git a/library/Vspheredb/Polling/SyncTask/TaggingObjectTagSyncTask.php b/library/Vspheredb/Polling/SyncTask/TaggingObjectTagSyncTask.php
index 9f9060ff..375dbf3b 100644
--- a/library/Vspheredb/Polling/SyncTask/TaggingObjectTagSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/TaggingObjectTagSyncTask.php
@@ -8,9 +8,11 @@
 
 class TaggingObjectTagSyncTask extends TaggingSyncTask
 {
-    protected $label = 'Object Tags';
-    protected $tableName = TaggingObjectTag::TABLE;
-    protected $objectClass = TaggingObjectTag::class;
+    protected string $label = 'Object Tags';
+
+    protected string $tableName = TaggingObjectTag::TABLE;
+
+    protected string $objectClass = TaggingObjectTag::class;
 
     public function run(RestApi $api): PromiseInterface
     {
diff --git a/library/Vspheredb/Polling/SyncTask/TaggingSyncTask.php b/library/Vspheredb/Polling/SyncTask/TaggingSyncTask.php
index 2c5f9f1a..9fd53694 100644
--- a/library/Vspheredb/Polling/SyncTask/TaggingSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/TaggingSyncTask.php
@@ -6,5 +6,5 @@
 
 abstract class TaggingSyncTask extends SyncTask implements RestApiTask
 {
-    protected $syncStoreClass = TaggingSyncStore::class;
+    protected string $syncStoreClass = TaggingSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/TaggingTagSyncTask.php b/library/Vspheredb/Polling/SyncTask/TaggingTagSyncTask.php
index 10d96083..90073c99 100644
--- a/library/Vspheredb/Polling/SyncTask/TaggingTagSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/TaggingTagSyncTask.php
@@ -8,9 +8,11 @@
 
 class TaggingTagSyncTask extends TaggingSyncTask
 {
-    protected $label = 'Tags';
-    protected $tableName = TaggingTag::TABLE;
-    protected $objectClass = TaggingTag::class;
+    protected string $label = 'Tags';
+
+    protected string $tableName = TaggingTag::TABLE;
+
+    protected string $objectClass = TaggingTag::class;
 
     public function run(RestApi $api): PromiseInterface
     {
diff --git a/library/Vspheredb/Polling/SyncTask/VirtualMachineSyncTask.php b/library/Vspheredb/Polling/SyncTask/VirtualMachineSyncTask.php
index 1ce11f1c..272ea76f 100644
--- a/library/Vspheredb/Polling/SyncTask/VirtualMachineSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/VirtualMachineSyncTask.php
@@ -9,10 +9,15 @@
 
 class VirtualMachineSyncTask extends SyncTask
 {
-    protected $label = 'Virtual Machines';
-    protected $tableName = 'virtual_machine';
-    protected $objectClass = VirtualMachine::class;
-    protected $selectSetClass = VirtualMachineSelectSet::class;
-    protected $propertySetClass = VirtualMachinePropertySet::class;
-    protected $syncStoreClass = ObjectSyncStore::class;
+    protected string $label = 'Virtual Machines';
+
+    protected string $tableName = 'virtual_machine';
+
+    protected string $objectClass = VirtualMachine::class;
+
+    protected string $selectSetClass = VirtualMachineSelectSet::class;
+
+    protected string $propertySetClass = VirtualMachinePropertySet::class;
+
+    protected string $syncStoreClass = ObjectSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/VmDatastoreUsageSyncTask.php b/library/Vspheredb/Polling/SyncTask/VmDatastoreUsageSyncTask.php
index d6c32580..5046fcf9 100644
--- a/library/Vspheredb/Polling/SyncTask/VmDatastoreUsageSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/VmDatastoreUsageSyncTask.php
@@ -10,10 +10,15 @@
 class VmDatastoreUsageSyncTask extends SyncTask
 {
     // TODO: refresh logic! -> pick outdated ones, trigger refresh
-    protected $label = 'VM Datastore Usage';
-    protected $tableName = 'vm_datastore_usage';
-    protected $objectClass = VmDatastoreUsage::class;
-    protected $selectSetClass = VirtualMachineSelectSet::class;
-    protected $propertySetClass = VmDatastoreUsagePropertySet::class;
-    protected $syncStoreClass = VmDatastoreUsageSyncStore::class;
+    protected string $label = 'VM Datastore Usage';
+
+    protected string $tableName = 'vm_datastore_usage';
+
+    protected string $objectClass = VmDatastoreUsage::class;
+
+    protected string $selectSetClass = VirtualMachineSelectSet::class;
+
+    protected string $propertySetClass = VmDatastoreUsagePropertySet::class;
+
+    protected string $syncStoreClass = VmDatastoreUsageSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/VmDiskUsageSyncTask.php b/library/Vspheredb/Polling/SyncTask/VmDiskUsageSyncTask.php
index 243cf30a..57405057 100644
--- a/library/Vspheredb/Polling/SyncTask/VmDiskUsageSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/VmDiskUsageSyncTask.php
@@ -9,10 +9,15 @@
 
 class VmDiskUsageSyncTask extends SyncTask
 {
-    protected $label = 'VM Disk Usage';
-    protected $tableName = 'vm_disk_usage';
-    protected $objectClass = VmDiskUsage::class;
-    protected $selectSetClass = VirtualMachineSelectSet::class;
-    protected $propertySetClass = VmDiskUsagePropertySet::class;
-    protected $syncStoreClass = VmDiskUsageSyncStore::class;
+    protected string $label = 'VM Disk Usage';
+
+    protected string $tableName = 'vm_disk_usage';
+
+    protected string $objectClass = VmDiskUsage::class;
+
+    protected string $selectSetClass = VirtualMachineSelectSet::class;
+
+    protected string $propertySetClass = VmDiskUsagePropertySet::class;
+
+    protected string $syncStoreClass = VmDiskUsageSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/VmEventHistorySyncTask.php b/library/Vspheredb/Polling/SyncTask/VmEventHistorySyncTask.php
index 003f0898..45f08b82 100644
--- a/library/Vspheredb/Polling/SyncTask/VmEventHistorySyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/VmEventHistorySyncTask.php
@@ -9,9 +9,11 @@
 
 class VmEventHistorySyncTask extends SyncTask implements StandaloneTask
 {
-    protected $label = 'Events';
-    protected $tableName = 'vm_event_history';
-    protected $syncStoreClass = VmEventHistorySyncStore::class;
+    protected string $label = 'Events';
+
+    protected string $tableName = 'vm_event_history';
+
+    protected string $syncStoreClass = VmEventHistorySyncStore::class;
 
     public function run(VsphereApi $api, LoggerInterface $logger): PromiseInterface
     {
diff --git a/library/Vspheredb/Polling/SyncTask/VmHardwareSyncTask.php b/library/Vspheredb/Polling/SyncTask/VmHardwareSyncTask.php
index 697100d6..24652824 100644
--- a/library/Vspheredb/Polling/SyncTask/VmHardwareSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/VmHardwareSyncTask.php
@@ -2,7 +2,6 @@
 
 namespace Icinga\Module\Vspheredb\Polling\SyncTask;
 
-use gipfl\Json\JsonString;
 use Icinga\Module\Vspheredb\DbObject\VmHardware;
 use Icinga\Module\Vspheredb\Polling\PropertySet\VmHardwarePropertySet;
 use Icinga\Module\Vspheredb\Polling\SelectSet\VirtualMachineSelectSet;
@@ -10,14 +9,19 @@
 
 class VmHardwareSyncTask extends SyncTask
 {
-    protected $label = 'VM Hardware';
-    protected $tableName = 'vm_hardware';
-    protected $objectClass = VmHardware::class;
-    protected $selectSetClass = VirtualMachineSelectSet::class;
-    protected $propertySetClass = VmHardwarePropertySet::class;
-    protected $syncStoreClass = VmHardwareSyncStore::class;
+    protected string $label = 'VM Hardware';
 
-    public function tweakResult($result)
+    protected string $tableName = 'vm_hardware';
+
+    protected string $objectClass = VmHardware::class;
+
+    protected string $selectSetClass = VirtualMachineSelectSet::class;
+
+    protected string $propertySetClass = VmHardwarePropertySet::class;
+
+    protected string $syncStoreClass = VmHardwareSyncStore::class;
+
+    public function tweakResult($result): void
     {
         $whitelist = [
             // Problem with config.hardware: some properties are binary,
@@ -45,10 +49,10 @@ public function tweakResult($result)
             'capacityInBytes',
             'split',
             'writeThrough',
-            'thinProvisioned',
+            'thinProvisioned'
         ];
         // $unset = []; // used only when looking for new properties
-        foreach ($result as $key => $value) {
+        foreach ($result as $value) {
             if (isset($value['config.hardware']->device)) {
                 foreach ($value['config.hardware']->device as $device) {
                     foreach (array_keys((array) $device) as $k) {
diff --git a/library/Vspheredb/Polling/SyncTask/VmQuickStatsSyncTask.php b/library/Vspheredb/Polling/SyncTask/VmQuickStatsSyncTask.php
index d76501d7..03584e91 100644
--- a/library/Vspheredb/Polling/SyncTask/VmQuickStatsSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/VmQuickStatsSyncTask.php
@@ -9,10 +9,15 @@
 
 class VmQuickStatsSyncTask extends SyncTask
 {
-    protected $label = 'VM Quick Stats';
-    protected $tableName = 'vm_quick_stats';
-    protected $objectClass = VmQuickStats::class;
-    protected $selectSetClass = VirtualMachineSelectSet::class;
-    protected $propertySetClass = VmQuickStatsPropertySet::class;
-    protected $syncStoreClass = ObjectSyncStore::class;
+    protected string $label = 'VM Quick Stats';
+
+    protected string $tableName = 'vm_quick_stats';
+
+    protected string $objectClass = VmQuickStats::class;
+
+    protected string $selectSetClass = VirtualMachineSelectSet::class;
+
+    protected string $propertySetClass = VmQuickStatsPropertySet::class;
+
+    protected string $syncStoreClass = ObjectSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/SyncTask/VmSnapshotSyncTask.php b/library/Vspheredb/Polling/SyncTask/VmSnapshotSyncTask.php
index c3dfec1f..2e03a958 100644
--- a/library/Vspheredb/Polling/SyncTask/VmSnapshotSyncTask.php
+++ b/library/Vspheredb/Polling/SyncTask/VmSnapshotSyncTask.php
@@ -9,10 +9,15 @@
 
 class VmSnapshotSyncTask extends SyncTask
 {
-    protected $label = 'VM Snapshots';
-    protected $tableName = 'vm_snapshot';
-    protected $objectClass = VmSnapshot::class;
-    protected $selectSetClass = VirtualMachineSelectSet::class;
-    protected $propertySetClass = VmSnapshotPropertySet::class;
-    protected $syncStoreClass = VmSnapshotSyncStore::class;
+    protected string $label = 'VM Snapshots';
+
+    protected string $tableName = 'vm_snapshot';
+
+    protected string $objectClass = VmSnapshot::class;
+
+    protected string $selectSetClass = VirtualMachineSelectSet::class;
+
+    protected string $propertySetClass = VmSnapshotPropertySet::class;
+
+    protected string $syncStoreClass = VmSnapshotSyncStore::class;
 }
diff --git a/library/Vspheredb/Polling/VsphereApi.php b/library/Vspheredb/Polling/VsphereApi.php
index 3258ddc0..dcc83a90 100644
--- a/library/Vspheredb/Polling/VsphereApi.php
+++ b/library/Vspheredb/Polling/VsphereApi.php
@@ -28,52 +28,47 @@
 use Icinga\Module\Vspheredb\Polling\SelectSet\SelectSet;
 use Icinga\Module\Vspheredb\SafeCacheDir;
 use Icinga\Module\Vspheredb\VmwareDataType\ManagedObjectReference;
+use InvalidArgumentException;
 use Psr\Log\LoggerInterface;
 use Ramsey\Uuid\Uuid;
 use Ramsey\Uuid\UuidInterface;
 use React\EventLoop\LoopInterface;
 use React\Promise\Deferred;
 use React\Promise\PromiseInterface;
+use RuntimeException;
+use SoapFault;
 
 use function React\Promise\reject;
 use function React\Promise\resolve;
 
 class VsphereApi
 {
-    /** @var ServerInfo */
-    protected $server;
+    protected ServerInfo $server;
 
-    /** @var LoggerInterface */
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    /** @var CurlAsync */
-    private $curl;
+    private CurlAsync $curl;
 
     /** @var SoapClient */
     private $soapClient;
 
-    /** @var ManagedObjectReference */
-    private $serviceInstanceRef;
+    private ManagedObjectReference $serviceInstanceRef;
 
-    private $initialWsdlFile;
+    private ?string $initialWsdlFile;
 
     /** @var ServiceContent */
     private $serviceInstance;
 
-    /** @var CookieStore */
-    private $cookieStore;
+    private CookieStore $cookieStore;
 
-    /** @var LoopInterface */
-    private $loop;
+    private LoopInterface $loop;
 
-    /** @var ?ManagedObjectReference */
-    private $eventCollector;
+    private ?ManagedObjectReference $eventCollector = null;
 
-    /** @var int */
-    private $lastEventTimestamp;
+    private ?int $lastEventTimestamp = null;
 
     public function __construct(
-        $initialWsdlFile,
+        ?string $initialWsdlFile,
         ServerInfo $server,
         CurlAsync $curl,
         LoopInterface $loop,
@@ -100,11 +95,7 @@ public function __construct(
      */
     public function getServiceInstance(): PromiseInterface
     {
-        if ($this->serviceInstance === null) {
-            $this->serviceInstance = $this->retrieveServiceContent();
-        }
-
-        return resolve($this->serviceInstance);
+        return resolve($this->serviceInstance ??= $this->retrieveServiceContent());
     }
 
     /**
@@ -121,6 +112,7 @@ public function getCurrentTime(): PromiseInterface
      * Really fetch the ServiceInstance
      *
      * @return PromiseInterface<ServiceContent>
+     *
      * @see getServiceInstance()
      *
      */
@@ -156,6 +148,7 @@ public function eventuallyLogin(): PromiseInterface
                 }
                 $this->logger->notice($message);
                 $this->cookieStore->forgetCookies();
+
                 return $this->login();
             });
         } else {
@@ -167,6 +160,7 @@ public function eventuallyLogin(): PromiseInterface
      * API login
      *
      * This will retrieve a session cookie and pass it with subsequent requests
+     *
      * @return PromiseInterface<UserSession>
      */
     public function login(): PromiseInterface
@@ -174,7 +168,7 @@ public function login(): PromiseInterface
         $this->logger->debug(sprintf('Sending Login request to %s', $this->makeLocation()));
         return $this->callOnServiceInstanceObject('sessionManager', 'Login', [
             'userName' => $this->server->get('username'),
-            'password' => $this->server->get('password'),
+            'password' => $this->server->get('password')
         ])->then(function ($result) {
             return $result->returnval;
         });
@@ -210,19 +204,23 @@ public function eventuallyLogout(): PromiseInterface
 
     /**
      * @param ManagedObjectReference $self
-     * @param $method
+     * @param string $method
      * @param array $arguments
+     *
      * @return PromiseInterface
      */
-    public function call(ManagedObjectReference $self, $method, $arguments = []): PromiseInterface
+    public function call(ManagedObjectReference $self, string $method, array $arguments = []): PromiseInterface
     {
         return $this->soapClient->call($method, [[
                 '_this' => $self
             ] + $arguments]);
     }
 
-    public function callOnServiceInstanceObject($serviceInstanceObjectName, $method, $arguments = [])
-    {
+    public function callOnServiceInstanceObject(
+        string $serviceInstanceObjectName,
+        string $method,
+        array $arguments = []
+    ): PromiseInterface {
         $property = $serviceInstanceObjectName;
         return $this->getServiceInstance()
             ->then(function (ServiceContent $serviceContent) use ($property, $method, $arguments) {
@@ -231,7 +229,7 @@ public function callOnServiceInstanceObject($serviceInstanceObjectName, $method,
                 }
                 $ref = $serviceContent->$property;
                 if (! $ref instanceof ManagedObjectReference) {
-                    return reject(new \InvalidArgumentException(
+                    return reject(new InvalidArgumentException(
                         "ServiceContent.$property is no a ManagedObjectReference"
                     ));
                 }
@@ -242,11 +240,14 @@ public function callOnServiceInstanceObject($serviceInstanceObjectName, $method,
 
     /**
      * @param ManagedObjectReference $object
-     * @param array|null $properties
+     * @param ?array $properties
+     *
      * @return PromiseInterface<?ManagedObject>
      */
-    public function requireSingleObjectProperties(ManagedObjectReference $object, $properties = null): PromiseInterface
-    {
+    public function requireSingleObjectProperties(
+        ManagedObjectReference $object,
+        ?array $properties = null
+    ): PromiseInterface {
         return $this->fetchSingleObject($object, $properties)->then(function ($resultObject) use ($object) {
             if ($resultObject) {
                 return $resultObject;
@@ -261,10 +262,11 @@ public function requireSingleObjectProperties(ManagedObjectReference $object, $p
 
     /**
      * @param ManagedObjectReference $object
-     * @param array|null $properties
+     * @param ?array $properties
+     *
      * @return PromiseInterface<?ManagedObject>
      */
-    public function fetchSingleObject(ManagedObjectReference $object, $properties = null): PromiseInterface
+    public function fetchSingleObject(ManagedObjectReference $object, ?array $properties = null): PromiseInterface
     {
         return $this->retrieveProperties([$this->singleObjectSpecSet($object, $properties)])
             ->then(function (RetrieveResult $result) use ($object) {
@@ -283,7 +285,7 @@ public function fetchSingleObject(ManagedObjectReference $object, $properties =
             });
     }
 
-    public function fetchCustomFieldsManager()
+    public function fetchCustomFieldsManager(): PromiseInterface
     {
         return $this->getServiceInstance()->then(function (ServiceContent $serviceContent) {
             if (! isset($serviceContent->customFieldsManager)) {
@@ -297,11 +299,14 @@ public function fetchCustomFieldsManager()
 
     /**
      * @param ManagedObjectReference $object
-     * @param array|null $properties
+     * @param ?array $properties
+     *
      * @return PromiseInterface<?ObjectContent>
      */
-    public function fetchSingleObjectProperties(ManagedObjectReference $object, $properties = null): PromiseInterface
-    {
+    public function fetchSingleObjectProperties(
+        ManagedObjectReference $object,
+        ?array $properties = null
+    ): PromiseInterface {
         return $this->retrieveProperties([$this->singleObjectSpecSet($object, $properties)])
             ->then(function (RetrieveResult $result) use ($object) {
                 if (empty($result->objects)) {
@@ -314,6 +319,7 @@ public function fetchSingleObjectProperties(ManagedObjectReference $object, $pro
                         $object->getLogName()
                     )));
                 }
+
                 return $result->objects[0];
             });
     }
@@ -321,6 +327,7 @@ public function fetchSingleObjectProperties(ManagedObjectReference $object, $pro
      * TODO: Can be used for mass requests once we deal with the token in the RetrieveResult
      *
      * @param PropertyFilterSpec[] $specSet
+     *
      * @return PromiseInterface<RetrieveResult>
      */
     public function retrieveProperties(array $specSet): PromiseInterface
@@ -341,18 +348,19 @@ public function retrieveProperties(array $specSet): PromiseInterface
                     }
                     $result = new RetrieveResult();
                     $result->objects = $objects;
+
                     return $result;
                 });
             });
         });
     }
 
-    public function getCurrentSession()
+    public function getCurrentSession(): PromiseInterface
     {
         return $this->getServiceInstance()->then(function (ServiceContent $content) {
             return $this->fetchSingleObject($content->sessionManager, [
                 'currentSession',
-                'defaultLocale',
+                'defaultLocale'
             ])->then(function (SessionManager $manager) {
                 if (isset($manager->currentSession)) {
                     return $manager->currentSession;
@@ -386,10 +394,10 @@ public function fetchUniqueId(): PromiseInterface
                     [PropertySpec::create('HostSystem', ['hardware.systemInfo.uuid'])]
                 )])->then(function ($result) {
                     if (empty($result)) {
-                        throw new \RuntimeException('Unable to fetch host object for ESXi system');
+                        throw new RuntimeException('Unable to fetch host object for ESXi system');
                     }
                     if (count($result) > 1) {
-                        throw new \RuntimeException(sprintf(
+                        throw new RuntimeException(sprintf(
                             'Expected to get one host from an ESXi system, got %d',
                             count($result)
                         ));
@@ -398,7 +406,7 @@ public function fetchUniqueId(): PromiseInterface
                         return Uuid::fromString($result[0]['hardware.systemInfo.uuid']);
                     }
 
-                    throw new \RuntimeException('Got no hardware.systemInfo.uuid from ESXi host');
+                    throw new RuntimeException('Got no hardware.systemInfo.uuid from ESXi host');
                 });
             } else {
                 return Uuid::fromString($content->about->instanceUuid);
@@ -406,14 +414,14 @@ public function fetchUniqueId(): PromiseInterface
         });
     }
 
-    public function setLastEventTimestamp($timestamp)
+    public function setLastEventTimestamp(?int $timestamp): static
     {
         $this->lastEventTimestamp = $timestamp;
 
         return $this;
     }
 
-    protected function fetchFullResult(RetrieveResult $result, &$objects)
+    protected function fetchFullResult(RetrieveResult $result, array &$objects): PromiseInterface
     {
         $deferred = new Deferred();
         if ($result->hasMoreResults()) {
@@ -437,7 +445,7 @@ protected function fetchFullResult(RetrieveResult $result, &$objects)
         return $deferred->promise();
     }
 
-    protected function getPropertyCollector()
+    protected function getPropertyCollector(): PromiseInterface
     {
         return $this->getServiceInstance()->then(function (ServiceContent $serviceContent) {
             return $serviceContent->propertyCollector;
@@ -458,7 +466,7 @@ protected function requireRetrieveResult($result)
         return $result;
     }
 
-    protected function continueFetchProperties($token)
+    protected function continueFetchProperties($token): PromiseInterface
     {
         return $this->callOnServiceInstanceObject('propertyCollector', 'ContinueRetrievePropertiesEx', [
             'token' => $token
@@ -467,7 +475,7 @@ protected function continueFetchProperties($token)
         });
     }
 
-    protected function singleObjectSpecSet(ManagedObjectReference $moRef, $properties = null)
+    protected function singleObjectSpecSet(ManagedObjectReference $moRef, ?array $properties = null): PropertyFilterSpec
     {
         return PropertyFilterSpec::create(
             [ObjectSpec::create($moRef, null, false)],
@@ -475,7 +483,7 @@ protected function singleObjectSpecSet(ManagedObjectReference $moRef, $propertie
         );
     }
 
-    protected function fetchSpecSet(array $specSet)
+    protected function fetchSpecSet(array $specSet): PromiseInterface
     {
         return $this->retrieveProperties($specSet)->then(function (RetrieveResult $result) {
             return $result->jsonSerialize();
@@ -483,12 +491,15 @@ protected function fetchSpecSet(array $specSet)
     }
 
     /**
-     * @param string|SelectSet $selectSetClass It's a string, SelectSet helps the IDE
-     * @param string|PropertySet $propertySetClass It's a string, PropertySet helps the IDE
+     * @param class-string<SelectSet> $selectSetClass
+     * @param class-string<PropertySet> $propertySetClass
+     *
      * @return PromiseInterface
      */
-    public function fetchBySelectAndPropertySetClass($selectSetClass, $propertySetClass)
-    {
+    public function fetchBySelectAndPropertySetClass(
+        string $selectSetClass,
+        string $propertySetClass
+    ): PromiseInterface {
         return $this->getRootFolder()->then(function ($rootFolder) use ($selectSetClass, $propertySetClass) {
             return $this->fetchSpecSet([PropertyFilterSpec::create(
                 [ObjectSpec::create($rootFolder, $selectSetClass::create(), false)],
@@ -497,26 +508,26 @@ public function fetchBySelectAndPropertySetClass($selectSetClass, $propertySetCl
         });
     }
 
-    public function readNextEvents()
+    public function readNextEvents(): PromiseInterface
     {
         return $this->callOnEventCollector('ReadNextEvents', [
-            'maxCount' => 1000,
+            'maxCount' => 1000
         ]);
     }
 
-    public function rewindEventCollector()
+    public function rewindEventCollector(): PromiseInterface
     {
         return $this->callOnEventCollector('RewindCollector');
     }
 
-    public function fetchPerformanceManager()
+    public function fetchPerformanceManager(): PromiseInterface
     {
         return $this->getServiceInstance()->then(function (ServiceContent $serviceContent) {
             return $this->fetchSingleObject($serviceContent->perfManager);
         });
     }
 
-    protected function getEventCollector()
+    protected function getEventCollector(): PromiseInterface|ManagedObjectReference
     {
         if ($this->eventCollector) {
             return resolve($this->eventCollector);
@@ -531,11 +542,11 @@ protected function getEventCollector()
                 });
             }
 
-            throw new \RuntimeException('EventCollector reference expected, got ' . var_export($result, 1));
+            throw new RuntimeException('EventCollector reference expected, got ' . var_export($result, 1));
         });
     }
 
-    protected function callOnEventCollector($method, $arguments = [])
+    protected function callOnEventCollector($method, $arguments = []): PromiseInterface
     {
         // Sample:
         // $collector = new ManagedObjectReference(
@@ -550,12 +561,12 @@ protected function callOnEventCollector($method, $arguments = [])
 
                 return [];
             }, function (Exception $e) {
-                if ($e instanceof \SoapFault) {
+                if ($e instanceof SoapFault) {
                     if (isset($e->detail)) {
                         $details = (array)$e->detail;
                         if (current($details)->enc_stype === 'ManagedObjectNotFound') {
                             $this->eventCollector = null;
-                            throw new \RuntimeException(
+                            throw new RuntimeException(
                                 'Dropping formerly known EventCollector: ' . $e->getMessage(),
                                 $e->getCode(),
                                 $e
@@ -568,7 +579,7 @@ protected function callOnEventCollector($method, $arguments = [])
         });
     }
 
-    protected function createEventCollector($lastEventTimestamp = null)
+    protected function createEventCollector($lastEventTimestamp = null): PromiseInterface
     {
         $spec = new EventFilterSpec();
         $spec->type = $this->getRequiredEventTypes();
@@ -584,7 +595,7 @@ protected function createEventCollector($lastEventTimestamp = null)
     /**
      * @throws Exception e.g.: SOAP-ERROR: Parsing Schema: can't import schema from '/tmp/[..]/vim-types.xsd
      */
-    protected function prepareSoapClient()
+    protected function prepareSoapClient(): void
     {
         $this->soapClient = new SoapClient($this->curl, $this->initialWsdlFile, [
             'trace'              => true,
@@ -594,7 +605,7 @@ protected function prepareSoapClient()
             'classmap'           => ApiClassMap::getMap(),
             'features'           => SOAP_SINGLE_ELEMENT_ARRAYS | SOAP_USE_XSI_ARRAY_TYPE,
             'cache_wsdl'         => WSDL_CACHE_NONE,
-            'compression'        => SOAP_COMPRESSION_ACCEPT | SOAP_COMPRESSION_GZIP,
+            'compression'        => SOAP_COMPRESSION_ACCEPT | SOAP_COMPRESSION_GZIP
         ], CurlOptions::forServerInfo($this->server), $this->logger);
         $this->soapClient->setCookieStore($this->cookieStore);
     }
@@ -604,12 +615,12 @@ protected function prepareSoapClient()
      *
      * @return string
      */
-    protected function makeLocation()
+    protected function makeLocation(): string
     {
         return $this->server->getUrl() . '/sdk';
     }
 
-    protected function getRequiredEventTypes()
+    protected function getRequiredEventTypes(): array
     {
         return [
             'AlarmAcknowledgedEvent',
@@ -642,7 +653,7 @@ protected function getRequiredEventTypes()
             'VmBeingClonedEvent',
             'VmBeingClonedNoFolderEvent',
             'VmClonedEvent',
-            'VmCloneFailedEvent',
+            'VmCloneFailedEvent'
         ];
     }
 }
diff --git a/library/Vspheredb/Polling/WsdlLoader.php b/library/Vspheredb/Polling/WsdlLoader.php
index dd9b2312..0c3fa7ac 100644
--- a/library/Vspheredb/Polling/WsdlLoader.php
+++ b/library/Vspheredb/Polling/WsdlLoader.php
@@ -28,7 +28,7 @@ class WsdlLoader
      *
      * @var array
      */
-    protected $requiredFiles = [
+    protected array $requiredFiles = [
         'vimService.wsdl',
         'vim.wsdl',
         'core-types.xsd',
@@ -37,29 +37,27 @@ class WsdlLoader
         'reflect-types.xsd',
         'reflect-messagetypes.xsd',
         'vim-types.xsd',
-        'vim-messagetypes.xsd',
+        'vim-messagetypes.xsd'
     ];
 
-    protected $logger;
+    protected LoggerInterface $logger;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
-    protected $cacheDir;
+    protected string $cacheDir;
 
-    protected $curl;
+    protected CurlAsync $curl;
 
-    protected $serverInfo;
+    protected ServerInfo $serverInfo;
 
-    protected $baseUrl;
+    protected string $baseUrl;
 
     /** @var PromiseInterface[] */
-    protected $pending = [];
+    protected array $pending = [];
 
-    /** @var ?Deferred */
-    protected $deferred;
+    protected ?Deferred $deferred = null;
 
-    public function __construct($cacheDir, LoggerInterface $logger, ServerInfo $server, CurlAsync $curl)
+    public function __construct(string $cacheDir, LoggerInterface $logger, ServerInfo $server, CurlAsync $curl)
     {
         $this->cacheDir = $cacheDir;
         $this->logger = $logger;
@@ -68,7 +66,7 @@ public function __construct($cacheDir, LoggerInterface $logger, ServerInfo $serv
         $this->baseUrl = $server->getUrl();
     }
 
-    public function fetchInitialWsdlFile(LoopInterface $loop)
+    public function fetchInitialWsdlFile(LoopInterface $loop): PromiseInterface
     {
         $this->loop = $loop;
         return $this->fetchFiles()->then(function () {
@@ -76,12 +74,12 @@ public function fetchInitialWsdlFile(LoopInterface $loop)
         });
     }
 
-    protected function getInitialFilename()
+    protected function getInitialFilename(): string
     {
         return $this->cacheDir . '/' . $this->requiredFiles[0];
     }
 
-    public function stop()
+    public function stop(): void
     {
         if ($this->deferred) {
             $deferred = $this->deferred;
@@ -95,7 +93,7 @@ public function stop()
         }
     }
 
-    public function flushWsdlCache()
+    public function flushWsdlCache(): void
     {
         $dir = $this->cacheDir;
         $unlinked = false;
@@ -147,10 +145,11 @@ protected function processFileFailure(Exception $e, string $file): void
         }
     }
 
-    protected function fetchFiles()
+    protected function fetchFiles(): PromiseInterface
     {
         if ($this->deferred) {
             $this->logger->notice('Calling WsdlLoader::fetchFiles while already loading');
+
             return $this->deferred->promise();
         }
         $this->deferred = $deferred = new Deferred();
@@ -181,7 +180,7 @@ protected function fetchFiles()
         return $deferred->promise();
     }
 
-    protected function resolveIfReady()
+    protected function resolveIfReady(): void
     {
         if (empty($this->pending)) {
             $deferred = $this->deferred;
@@ -198,7 +197,7 @@ protected function resolveIfReady()
         }
     }
 
-    protected function url($file)
+    protected function url($file): string
     {
         return $this->baseUrl . "/sdk/$file";
     }
diff --git a/library/Vspheredb/ProvidedHook/Director/DataTypeMonitoringRule.php b/library/Vspheredb/ProvidedHook/Director/DataTypeMonitoringRule.php
index 8693220a..60d1c800 100644
--- a/library/Vspheredb/ProvidedHook/Director/DataTypeMonitoringRule.php
+++ b/library/Vspheredb/ProvidedHook/Director/DataTypeMonitoringRule.php
@@ -5,12 +5,13 @@
 use Icinga\Module\Director\Hook\DataTypeHook;
 use Icinga\Module\Director\Web\Form\QuickForm;
 use Icinga\Module\Vspheredb\Monitoring\Rule\Definition\RuleSetRegistry;
+use Zend_Form_Element;
 
 class DataTypeMonitoringRule extends DataTypeHook
 {
     protected $db;
 
-    public function getFormElement($name, QuickForm $form)
+    public function getFormElement($name, QuickForm $form): Zend_Form_Element
     {
         $registry = RuleSetRegistry::default();
         $options = [];
@@ -26,7 +27,7 @@ public function getFormElement($name, QuickForm $form)
             $options[$set->getLabel()] = $current;
         }
         return $form->createElement('select', $name, [
-            'multiOptions' => ['' => $form->translate('- please choose -')] + $options,
+            'multiOptions' => ['' => $form->translate('- please choose -')] + $options
         ]);
     }
 }
diff --git a/library/Vspheredb/ProvidedHook/Director/ImportSource.php b/library/Vspheredb/ProvidedHook/Director/ImportSource.php
index d52b751b..de739c9f 100644
--- a/library/Vspheredb/ProvidedHook/Director/ImportSource.php
+++ b/library/Vspheredb/ProvidedHook/Director/ImportSource.php
@@ -16,6 +16,7 @@
 use Icinga\Module\Vspheredb\Web\Table\TableWithVCenterFilter;
 use Ramsey\Uuid\Uuid;
 use Zend_Db_Adapter_Abstract as ZfDb;
+use Zend_Db_Select;
 
 use function array_keys;
 
@@ -26,7 +27,7 @@
  */
 class ImportSource extends ImportSourceHook implements TableWithVCenterFilter, TableWithParentFilter
 {
-    protected $hostColumns = [
+    protected array $hostColumns = [
         'object_name'             => 'o.object_name',
         'uuid'                    => 'o.uuid',
         'parent_uuid'             => 'o.parent_uuid',
@@ -42,10 +43,10 @@ class ImportSource extends ImportSourceHook implements TableWithVCenterFilter, T
         'custom_values'           => 'h.custom_values',
         'tags'                    => '(NULL)',
         'internal_tags'           => 'o.tags',
-        'path'                    => '(NULL)',
+        'path'                    => '(NULL)'
     ];
 
-    protected $vmColumns = [
+    protected array $vmColumns = [
         'object_name'         => 'o.object_name',
         'moref'               => 'o.moref',
         'uuid'                => 'o.uuid',
@@ -69,10 +70,10 @@ class ImportSource extends ImportSourceHook implements TableWithVCenterFilter, T
         'tags'                => '(NULL)',
         'internal_tags'       => 'o.tags',
         'path'                => '(NULL)',
-        'resource_pool'       => 'rp.object_name',
+        'resource_pool'       => 'rp.object_name'
     ];
 
-    protected $computeResourceColumns = [
+    protected array $computeResourceColumns = [
         'object_name'              => 'o.object_name',
         'object_type'              => 'o.object_type',
         'uuid'                     => 'o.uuid',
@@ -88,10 +89,10 @@ class ImportSource extends ImportSourceHook implements TableWithVCenterFilter, T
         'total_memory_size_mb'     => 'cr.total_memory_size_mb',
         'tags'                     => '(NULL)',
         'internal_tags'            => 'o.tags',
-        'path'                     => '(NULL)',
+        'path'                     => '(NULL)'
     ];
 
-    protected $datastoreColumns = [
+    protected array $datastoreColumns = [
         'object_name'          => 'o.object_name',
         'uuid'                 => 'o.uuid',
         'parent_uuid'          => 'o.parent_uuid',
@@ -101,20 +102,18 @@ class ImportSource extends ImportSourceHook implements TableWithVCenterFilter, T
         'multiple_host_access' => 'ds.multiple_host_access',
         'tags'                 => '(NULL)',
         'internal_tags'        => 'o.tags',
-        'path'                 => '(NULL)',
+        'path'                 => '(NULL)'
     ];
 
-    /** @var ?array */
-    protected $parentFilterUuids = null;
-    /** @var ?array */
-    protected $vCenterFilterUuids = null;
+    protected ?array $parentFilterUuids = null;
+    protected ?array $vCenterFilterUuids = null;
 
-    public function getName()
+    public function getName(): string
     {
         return 'VMware vSphereDB';
     }
 
-    public static function addSettingsFormFields(QuickForm $form)
+    public static function addSettingsFormFields(QuickForm $form): void
     {
         assert($form instanceof ImportSourceForm);
         $form->addElement('select', 'object_type', [
@@ -123,35 +122,38 @@ public static function addSettingsFormFields(QuickForm $form)
                 'host_system'      => mt('vspheredb', 'Host Systems'),
                 'virtual_machine'  => mt('vspheredb', 'Virtual Machine'),
                 'compute_resource' => mt('vspheredb', 'Compute Resource'),
-                'datastore'        => mt('vspheredb', 'Datastore'),
+                'datastore'        => mt('vspheredb', 'Datastore')
             ]),
             'class'    => 'autosubmit',
             'required' => true
         ]);
         $form->addElement('select', 'vcenter_uuid', [
             'label' => mt('vspheredb', 'vCenter'),
-            'multiOptions' => ['' => mt('vspheredb', '- any -')] + self::enumVCenters(),
+            'multiOptions' => ['' => mt('vspheredb', '- any -')] + self::enumVCenters()
         ]);
         $type = $form->getSentOrObjectSetting('object_type');
         if ($type === 'virtual_machine') {
             $form->addBoolean('skip_powered_off', [
                 'label' => mt('vspheredb', 'Skip powered off VMs'),
-                'value' => 'n',
+                'value' => 'n'
             ]);
             $form->addBoolean('skip_templates', [
                 'label' => mt('vspheredb', 'Skip Templates'),
-                'value' => 'y',
+                'value' => 'y'
             ]);
         }
     }
 
+    /**
+     * @return array
+     */
     protected static function enumVCenters(): array
     {
         $db = Db::newConfiguredInstance();
         $pairs = $db->fetchPairs(
             $db->select()->from(['vc' => 'vcenter'], [
                 'uuid' => 'LOWER(HEX(vc.instance_uuid))',
-                'name' => "vc.name || ' (' || REPLACE(vc.api_name, 'VMware ', '') || ')'",
+                'name' => "vc.name || ' (' || REPLACE(vc.api_name, 'VMware ', '') || ')'"
             ])->order('vc.name')
         );
         $enum = [];
@@ -162,7 +164,12 @@ protected static function enumVCenters(): array
         return $enum;
     }
 
-    protected function eventuallyFilterVCenter($query)
+    /**
+     * @param Zend_Db_Select $query
+     *
+     * @return Zend_Db_Select
+     */
+    protected function eventuallyFilterVCenter(Zend_Db_Select $query): Zend_Db_Select
     {
         $vCenterUuid = $this->getSetting('vcenter_uuid');
         if ($vCenterUuid !== null && strlen($vCenterUuid) > 0) {
@@ -180,21 +187,15 @@ public function fetchData(): array
         $pathLookup = new BulkPathLookup($connection);
         $tagLookup = new TagLookup($connection);
         $objectType = $this->getSetting('object_type');
-        switch ($objectType) {
-            case 'host_system':
-                $query = $this->prepareHostsQuery($db);
-                break;
-            case 'virtual_machine':
-                $query = $this->prepareVmQuery($db);
-                break;
-            case 'compute_resource':
-                $query = $this->prepareComputeResourceQuery($db);
-                break;
-            case 'datastore':
-                $query = $this->prepareDatastoreQuery($db);
-                break;
-            default:
-                return [];
+        $query = match ($objectType) {
+            'host_system'      => $this->prepareHostsQuery($db),
+            'virtual_machine'  => $this->prepareVmQuery($db),
+            'compute_resource' => $this->prepareComputeResourceQuery($db),
+            'datastore'        => $this->prepareDatastoreQuery($db),
+            default            => null
+        };
+        if ($query === null) {
+            return [];
         }
         QueryHelper::applyOptionalVCenterFilter($db, $query, 'vc.instance_uuid', $this->vCenterFilterUuids);
         $this->applyOptionalParentFilter($query);
@@ -216,7 +217,12 @@ public function fetchData(): array
         return $result;
     }
 
-    public static function convertDbRowToJsonData($row)
+    /**
+     * @param object $row
+     *
+     * @return void
+     */
+    public static function convertDbRowToJsonData(object $row): void
     {
         $row->uuid = Uuid::fromBytes(DbUtil::binaryResult($row->uuid))->toString();
         if (isset($row->custom_values)) {
@@ -241,7 +247,12 @@ public static function convertDbRowToJsonData($row)
         }
     }
 
-    protected function prepareVmQuery(ZfDb $db)
+    /**
+     * @param ZfDb $db
+     *
+     * @return Zend_Db_Select
+     */
+    protected function prepareVmQuery(ZfDb $db): Zend_Db_Select
     {
         $query = $db->select()->from(['o' => 'object'], $this->vmColumns)
             ->join(['vm' => 'virtual_machine'], 'o.uuid = vm.uuid', [])
@@ -258,7 +269,12 @@ protected function prepareVmQuery(ZfDb $db)
         return $query;
     }
 
-    protected function prepareHostsQuery(ZfDb $db)
+    /**
+     * @param ZfDb $db
+     *
+     * @return Zend_Db_Select
+     */
+    protected function prepareHostsQuery(ZfDb $db): Zend_Db_Select
     {
         return $db->select()->from(['o' => 'object'], $this->hostColumns)->join(
             ['h' => 'host_system'],
@@ -267,7 +283,12 @@ protected function prepareHostsQuery(ZfDb $db)
         )->order('o.object_name')->order('o.uuid');
     }
 
-    protected function prepareComputeResourceQuery(ZfDb $db)
+    /**
+     * @param ZfDb $db
+     *
+     * @return Zend_Db_Select
+     */
+    protected function prepareComputeResourceQuery(ZfDb $db): Zend_Db_Select
     {
         return $db->select()->from(['o' => 'object'], $this->computeResourceColumns)->join(
             ['cr' => 'compute_resource'],
@@ -276,7 +297,12 @@ protected function prepareComputeResourceQuery(ZfDb $db)
         )->order('o.object_name')->order('o.uuid');
     }
 
-    protected function prepareDatastoreQuery(ZfDb $db)
+    /**
+     * @param ZfDb $db
+     *
+     * @return Zend_Db_Select
+     */
+    protected function prepareDatastoreQuery(ZfDb $db): Zend_Db_Select
     {
         return $db->select()->from(['o' => 'object'], $this->datastoreColumns)->join(
             ['ds' => 'datastore'],
@@ -285,7 +311,12 @@ protected function prepareDatastoreQuery(ZfDb $db)
         )->order('o.object_name')->order('o.uuid');
     }
 
-    protected function joinVCenter($query)
+    /**
+     * @param Zend_Db_Select $query
+     *
+     * @return Zend_Db_Select
+     */
+    protected function joinVCenter(Zend_Db_Select $query): Zend_Db_Select
     {
         return $query->join(
             ['vc' => 'vcenter'],
@@ -296,29 +327,31 @@ protected function joinVCenter($query)
 
     public function listColumns(): array
     {
-        switch ($this->getSetting('object_type')) {
-            case 'host_system':
-                return array_keys($this->hostColumns);
-            case 'virtual_machine':
-                return array_keys($this->vmColumns);
-            case 'compute_resource':
-                return array_keys($this->computeResourceColumns);
-            case 'datastore':
-                return array_keys($this->datastoreColumns);
-            default:
-                return [];
-        }
+        return match ($this->getSetting('object_type')) {
+            'host_system'      => array_keys($this->hostColumns),
+            'virtual_machine'  => array_keys($this->vmColumns),
+            'compute_resource' => array_keys($this->computeResourceColumns),
+            'datastore'        => array_keys($this->datastoreColumns),
+            default            => []
+        };
 
         // Alternative: return $this->callOnManagedObject('getDefaultPropertySet');
     }
 
+    /**
+     * @return string
+     */
     protected function getManagedObjectClass(): string
     {
-        return 'Icinga\\Module\\Vspheredb\\DbObject\\'
-            . $this->getSetting('object_type');
+        return 'Icinga\\Module\\Vspheredb\\DbObject\\' . $this->getSetting('object_type');
     }
 
-    protected function callOnManagedObject($method)
+    /**
+     * @param string $method
+     *
+     * @return mixed
+     */
+    protected function callOnManagedObject(string $method): mixed
     {
         $params = func_get_args();
         array_shift($params);
@@ -337,23 +370,41 @@ public static function getDefaultKeyColumnName(): ?string
         return 'object_name';
     }
 
-    public function filterVCenter(VCenter $vCenter): self
+    public function filterVCenter(VCenter $vCenter): static
     {
         return $this->filterVCenterUuids([$vCenter->getUuid()]);
     }
 
-    public function filterVCenterUuids(?array $uuids): self
+    /**
+     * @param ?array $uuids
+     *
+     * @return $this
+     */
+    public function filterVCenterUuids(?array $uuids): static
     {
         $this->vCenterFilterUuids = $uuids;
+
         return $this;
     }
 
-    public function filterParentUuids(?array $uuids)
+    /**
+     * @param ?array $uuids
+     *
+     * @return $this
+     */
+    public function filterParentUuids(?array $uuids): static
     {
         $this->parentFilterUuids = $uuids;
+
+        return $this;
     }
 
-    protected function applyOptionalParentFilter($query)
+    /**
+     * @param $query
+     *
+     * @return void
+     */
+    protected function applyOptionalParentFilter($query): void
     {
         if ($this->parentFilterUuids === null) {
             return;
diff --git a/library/Vspheredb/ProvidedHook/HostDetailExtensionTrait.php b/library/Vspheredb/ProvidedHook/HostDetailExtensionTrait.php
index 2fa3b1ef..10f6b523 100644
--- a/library/Vspheredb/ProvidedHook/HostDetailExtensionTrait.php
+++ b/library/Vspheredb/ProvidedHook/HostDetailExtensionTrait.php
@@ -26,9 +26,9 @@ trait HostDetailExtensionTrait
 {
     use Translation;
 
-    protected Db $db;
+    protected ?Db $db = null;
 
-    protected CheckRelatedLookup $lookup;
+    protected ?CheckRelatedLookup $lookup = null;
 
     /**
      * @param object<IcingaDBHost|MonitoringHost> $host
@@ -38,7 +38,7 @@ trait HostDetailExtensionTrait
      */
     abstract protected function getCustomVar(object $host, string $customVar): ?string;
 
-    public function init()
+    public function init(): void
     {
         $this->db = Db::newConfiguredInstance();
         $this->lookup = new CheckRelatedLookup($this->db);
@@ -49,7 +49,7 @@ public function init()
      *
      * @return ValidHtml
      */
-    public function renderVObject($vObject): ValidHtml
+    public function renderVObject(VirtualMachine|HostSystem $vObject): ValidHtml
     {
         $container = new HtmlElement('div', new Attributes([
             'class' => [
@@ -71,6 +71,11 @@ public function renderVObject($vObject): ValidHtml
         return $container;
     }
 
+    /**
+     * @param HostSystem $host
+     *
+     * @return ValidHtml
+     */
     protected function renderHostSystem(HostSystem $host): ValidHtml
     {
         $stats = HostQuickStats::loadFor($host);
@@ -92,6 +97,11 @@ protected function renderHostSystem(HostSystem $host): ValidHtml
             ));
     }
 
+    /**
+     * @param VirtualMachine $vm
+     *
+     * @return ValidHtml
+     */
     protected function renderVirtualMachine(VirtualMachine $vm): ValidHtml
     {
         $stats = VmQuickStats::loadFor($vm);
@@ -123,7 +133,7 @@ protected function renderVirtualMachine(VirtualMachine $vm): ValidHtml
      *
      * @return HostSystem|VirtualMachine|null
      */
-    protected function find(object $host, string $sourceType)
+    protected function find(object $host, string $sourceType): VirtualMachine|HostSystem|null
     {
         $spec = [
             'HostSystem'     => ['host', 'host_system', 'host'],
@@ -145,11 +155,10 @@ protected function find(object $host, string $sourceType)
                     continue;
                 }
 
-                if (substr($property, 0, 5) === 'vars.') {
-                    $value = $this->getCustomVar($host, substr($property, 5));
-                } else {
-                    $value = $host->$property;
-                }
+                $value = str_starts_with($property, 'vars.')
+                    ? $this->getCustomVar($host, substr($property, 5))
+                    : $host->$property;
+
                 if (! $value) {
                     continue;
                 }
@@ -162,7 +171,7 @@ protected function find(object $host, string $sourceType)
                 try {
                     $object = $this->lookup->findOneBy($type, $filter);
                     assert($object instanceof HostSystem || $object instanceof VirtualMachine);
-                } catch (NotFoundError $_) {
+                } catch (NotFoundError) {
                     continue;
                 }
 
diff --git a/library/Vspheredb/ProvidedHook/Monitoring/DetailviewExtension.php b/library/Vspheredb/ProvidedHook/Monitoring/DetailviewExtension.php
index b0752ee3..6cd3f51c 100644
--- a/library/Vspheredb/ProvidedHook/Monitoring/DetailviewExtension.php
+++ b/library/Vspheredb/ProvidedHook/Monitoring/DetailviewExtension.php
@@ -12,6 +12,11 @@ class DetailviewExtension extends DetailviewExtensionHook
 {
     use HostDetailExtensionTrait;
 
+    /**
+     * @param MonitoredObject $object
+     *
+     * @return ?ValidHtml
+     */
     public function getHtmlForObject(MonitoredObject $object): ?ValidHtml
     {
         if (! $object instanceof Host) {
diff --git a/library/Vspheredb/ProvidedHook/Vspheredb/PerfDataConsumerInfluxDb.php b/library/Vspheredb/ProvidedHook/Vspheredb/PerfDataConsumerInfluxDb.php
index 250cf595..33fe4f86 100644
--- a/library/Vspheredb/ProvidedHook/Vspheredb/PerfDataConsumerInfluxDb.php
+++ b/library/Vspheredb/ProvidedHook/Vspheredb/PerfDataConsumerInfluxDb.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\ProvidedHook\Vspheredb;
 
+use gipfl\Web\Form;
 use Icinga\Module\Vspheredb\Daemon\RemoteClient;
 use Icinga\Module\Vspheredb\Hook\PerfDataConsumerHook;
 use Icinga\Module\Vspheredb\Web\Form\ChooseInfluxDatabaseForm;
@@ -9,17 +10,17 @@
 
 class PerfDataConsumerInfluxDb extends PerfDataConsumerHook
 {
-    public static function getName()
+    public static function getName(): string
     {
         return 'InfluxDB';
     }
 
-    public function getConfigurationForm(RemoteClient $client)
+    public function getConfigurationForm(RemoteClient $client): Form
     {
         return new InfluxDbConnectionForm($this->loop, $client);
     }
 
-    public function getSubscriptionForm(RemoteClient $client)
+    public function getSubscriptionForm(RemoteClient $client): Form
     {
         return new ChooseInfluxDatabaseForm($this->loop, $client, $this);
     }
diff --git a/library/Vspheredb/SafeCacheDir.php b/library/Vspheredb/SafeCacheDir.php
index 0ff5d3c3..455735f2 100644
--- a/library/Vspheredb/SafeCacheDir.php
+++ b/library/Vspheredb/SafeCacheDir.php
@@ -6,30 +6,25 @@
 
 class SafeCacheDir
 {
-    protected static $currentUser;
+    protected static ?string $currentUser = null;
 
     /**
      * @return string
      */
-    public static function getDirectory()
+    public static function getDirectory(): string
     {
-        $directory = sprintf(
-            '%s/%s-%s',
-            sys_get_temp_dir(),
-            'iwebVsphere',
-            static::getCurrentUsername()
-        );
-
+        $directory = sprintf('%s/%s-%s', sys_get_temp_dir(), 'iwebVsphere', static::getCurrentUsername());
         static::claimDirectory($directory);
 
         return $directory;
     }
 
     /**
-     * @param $directory
+     * @param string $directory
+     *
      * @return string
      */
-    public static function getSubDirectory($directory)
+    public static function getSubDirectory(string $directory): string
     {
         $subDir = static::getDirectory() . "/$directory";
         static::claimDirectory($subDir);
@@ -38,9 +33,9 @@ public static function getSubDirectory($directory)
     }
 
     /**
-     * @param $directory
+     * @param string $directory
      */
-    protected static function claimDirectory($directory)
+    protected static function claimDirectory(string $directory): void
     {
         if (file_exists($directory)) {
             if (static::uidToName(fileowner($directory)) !== static::getCurrentUsername()) {
@@ -52,35 +47,31 @@ protected static function claimDirectory($directory)
             }
         } else {
             if (! @mkdir($directory, 0700)) {
-                throw new RuntimeException(sprintf(
-                    'Could not create %s',
-                    $directory
-                ));
+                throw new RuntimeException(sprintf('Could not create %s', $directory));
             }
         }
     }
 
     /**
-     * @return mixed
+     * @return string
      */
-    protected static function getCurrentUsername()
+    protected static function getCurrentUsername(): string
     {
         if (static::$currentUser === null) {
             if (function_exists('posix_geteuid')) {
                 static::$currentUser = static::uidToName(posix_geteuid());
             } else {
-                throw new RuntimeException(
-                    'POSIX methods not available, is php-posix installed and enabled?'
-                );
+                throw new RuntimeException('POSIX methods not available, is php-posix installed and enabled?');
             }
         }
 
         return static::$currentUser;
     }
 
-    protected static function uidToName($uid)
+    protected static function uidToName(int $uid): string
     {
         $info = posix_getpwuid($uid);
+
         return $info['name'];
     }
 }
diff --git a/library/Vspheredb/Severity.php b/library/Vspheredb/Severity.php
index 81127ae8..fc44c18a 100644
--- a/library/Vspheredb/Severity.php
+++ b/library/Vspheredb/Severity.php
@@ -9,13 +9,13 @@ class Severity
     protected static $colorToStateMap = [
         'green'  => 'Normal',
         'yellow' => 'Warning',
-        'red'    => 'Alert',
+        'red'    => 'Alert'
     ];
 
     protected static $stateToColorMap = [
         'Normal'  => 'green',
         'Warning' => 'yellow',
-        'Alert'   => 'red',
+        'Alert'   => 'red'
     ];
 
     /**
@@ -29,9 +29,9 @@ public static function colorToSeverity(string $color): string
     {
         if (array_key_exists($color, self::$colorToStateMap)) {
             return self::$colorToStateMap[$color];
-        } else {
-            throw new ProgrammingError('Color expected, got "%s"', $color);
         }
+
+        throw new ProgrammingError('Color expected, got "%s"', $color);
     }
 
     /**
@@ -45,8 +45,8 @@ public static function severityToColor(string $severity): string
     {
         if (array_key_exists($severity, self::$stateToColorMap)) {
             return self::$stateToColorMap[$severity];
-        } else {
-            throw new ProgrammingError('Severity expected, got "%s"', $severity);
         }
+
+        throw new ProgrammingError('Severity expected, got "%s"', $severity);
     }
 }
diff --git a/library/Vspheredb/Storable/PerfdataConsumer.php b/library/Vspheredb/Storable/PerfdataConsumer.php
index 38a80373..c821b4f1 100644
--- a/library/Vspheredb/Storable/PerfdataConsumer.php
+++ b/library/Vspheredb/Storable/PerfdataConsumer.php
@@ -10,19 +10,19 @@ class PerfdataConsumer implements DbStorableInterface
 {
     use DbStorable;
 
-    protected $tableName = 'perfdata_consumer';
+    protected string $tableName = 'perfdata_consumer';
 
-    protected $keyProperty = 'uuid';
+    protected string $keyProperty = 'uuid';
 
-    protected $defaultProperties = [
+    protected array $defaultProperties = [
         'uuid'             => null,
         'name'             => null,
         'implementation'   => null,
         'settings'         => null,
-        'enabled'          => null,
+        'enabled'          => null
     ];
 
-    public function settings()
+    public function settings(): mixed
     {
         $settings = $this->get('settings');
         if ($settings === null) {
diff --git a/library/Vspheredb/Storable/PerfdataSubscription.php b/library/Vspheredb/Storable/PerfdataSubscription.php
index 3874abbd..55c7b21d 100644
--- a/library/Vspheredb/Storable/PerfdataSubscription.php
+++ b/library/Vspheredb/Storable/PerfdataSubscription.php
@@ -8,6 +8,7 @@
 use gipfl\ZfDbStore\ZfDbStore;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Ramsey\Uuid\Uuid;
+use RuntimeException;
 
 class PerfdataSubscription implements DbStorableInterface
 {
@@ -15,19 +16,19 @@ class PerfdataSubscription implements DbStorableInterface
         set as parentSet;
     }
 
-    protected $tableName = 'perfdata_subscription';
+    protected string $tableName = 'perfdata_subscription';
 
-    protected $keyProperty = 'uuid';
+    protected string $keyProperty = 'uuid';
 
-    protected $defaultProperties = [
+    protected array $defaultProperties = [
         'uuid'          => null,
         'consumer_uuid' => null,
         'vcenter_uuid'  => null,
         'settings'      => null,
-        'enabled'       => null,
+        'enabled'       => null
     ];
 
-    public function set($property, $value)
+    public function set($property, $value): bool
     {
         if ($property === 'consumer') {
             $property = 'consumer_uuid';
@@ -49,7 +50,8 @@ public function settings()
 
     /**
      * @param VCenter $vCenter
-     * @return PerfdataSubscription|null
+     *
+     * @return ?PerfdataSubscription
      */
     public static function optionallyLoadForVCenter(VCenter $vCenter, ZfDbStore $store)
     {
@@ -64,7 +66,7 @@ public static function optionallyLoadForVCenter(VCenter $vCenter, ZfDbStore $sto
         }
 
         if (count($uuids) > 1) {
-            throw new \RuntimeException('More then one consumer per vCenter is currently not supported');
+            throw new RuntimeException('More then one consumer per vCenter is currently not supported');
         }
 
         return static::load($store, $uuids[0]);
diff --git a/library/Vspheredb/SyncRelated/SyncHelper.php b/library/Vspheredb/SyncRelated/SyncHelper.php
index f5fdb826..8935473e 100644
--- a/library/Vspheredb/SyncRelated/SyncHelper.php
+++ b/library/Vspheredb/SyncRelated/SyncHelper.php
@@ -3,18 +3,18 @@
 namespace Icinga\Module\Vspheredb\SyncRelated;
 
 use Exception;
-use gipfl\ZfDb\Adapter\Adapter;
 use Icinga\Module\Vspheredb\Db\DbObject;
 use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
+use Zend_Db_Adapter_Abstract;
 
 trait SyncHelper
 {
     /**
-     * @param \Zend_Db_Adapter_Abstract $db
-     * @param $callback
+     * @param Zend_Db_Adapter_Abstract $db
+     * @param callable $callback
      */
-    protected static function runAsTransaction($db, $callback)
+    protected static function runAsTransaction(Zend_Db_Adapter_Abstract $db, callable $callback): void
     {
         $db->beginTransaction();
         try {
@@ -32,13 +32,21 @@ protected static function runAsTransaction($db, $callback)
     }
 
     /**
-     * @param Adapter|\Zend_Db_Adapter_Abstract $db
+     * @param Zend_Db_Adapter_Abstract $db
      * @param DbObject[] $dbObjects
      * @param array $apiObjects
      * @param SyncStats $stats
+     *
+     * @return void
+     *
+     * @throws Exception
      */
-    protected function storeSyncObjects($db, array $dbObjects, array $apiObjects, SyncStats $stats)
-    {
+    protected function storeSyncObjects(
+        Zend_Db_Adapter_Abstract $db,
+        array $dbObjects,
+        array $apiObjects,
+        SyncStats $stats
+    ): void {
         $create = [];
         self::runAsTransaction($db, function () use ($apiObjects, &$dbObjects, $stats, &$create) {
             $modify = [];
@@ -73,14 +81,16 @@ protected function storeSyncObjects($db, array $dbObjects, array $apiObjects, Sy
     }
 
     /**
-     * @param string $class
+     * @param class-string<BaseDbObject> $class
      * @param string $table
      * @param VCenter $vCenter
+     *
+     * @return array
+     *
      * @return BaseDbObject[]
      */
-    protected static function loadAllForVCenter($class, $table, VCenter $vCenter)
+    protected static function loadAllForVCenter(string $class, string $table, VCenter $vCenter): array
     {
-        /** @var string|BaseDbObject $class */
         return $class::loadAll(
             $vCenter->getConnection(),
             $vCenter->getDb()
diff --git a/library/Vspheredb/SyncRelated/SyncStats.php b/library/Vspheredb/SyncRelated/SyncStats.php
index 24432df3..5f8d2ec5 100644
--- a/library/Vspheredb/SyncRelated/SyncStats.php
+++ b/library/Vspheredb/SyncRelated/SyncStats.php
@@ -3,52 +3,58 @@
 namespace Icinga\Module\Vspheredb\SyncRelated;
 
 use gipfl\Json\JsonSerialization;
+use ReturnTypeWillChange;
 
 class SyncStats implements JsonSerialization
 {
-    protected $created = 0;
-    protected $modified = 0;
-    protected $deleted = 0;
-    protected $totalFromApi = 0;
-    protected $totalFromDb = 0;
-    protected $label;
-
-    public function __construct($label)
+    protected int $created = 0;
+
+    protected int $modified = 0;
+
+    protected int $deleted = 0;
+
+    protected int $totalFromApi = 0;
+
+    protected int $totalFromDb = 0;
+
+    protected string $label;
+
+    public function __construct(string $label)
     {
         $this->label = $label;
     }
 
-    public function setFromApi($count)
+    public function setFromApi($count): void
     {
         $this->totalFromApi = $count;
     }
 
-    public function setFromDb($count)
+    public function setFromDb($count): void
     {
         $this->totalFromDb = $count;
     }
 
-    public function incCreated($count = 1)
+    public function incCreated($count = 1): void
     {
         $this->created += $count;
     }
 
-    public function incModified($count = 1)
+    public function incModified($count = 1): void
     {
         $this->modified += $count;
     }
 
-    public function incDeleted($count = 1)
+    public function incDeleted($count = 1): void
     {
         $this->deleted += $count;
     }
 
-    public function hasChanges()
+    public function hasChanges(): bool
     {
         return $this->created > 0 || $this->modified > 0 || $this->deleted > 0;
     }
 
-    public function getLogMessage()
+    public function getLogMessage(): string
     {
         return sprintf(
             "%s: %d new, %d modified, %d deleted (got %d from DB, %d from API)",
@@ -61,7 +67,7 @@ public function getLogMessage()
         );
     }
 
-    public static function fromSerialization($any)
+    public static function fromSerialization($any): static
     {
         $self = new static($any->label);
         $self->created      = $any->created;
@@ -73,8 +79,11 @@ public static function fromSerialization($any)
         return $self;
     }
 
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    /**
+     * @return object
+     */
+    public function jsonSerialize(): object
     {
         return (object) [
             'label'        => $this->label,
@@ -82,7 +91,7 @@ public function jsonSerialize()
             'modified'     => $this->modified,
             'deleted'      => $this->deleted,
             'totalFromApi' => $this->totalFromApi,
-            'totalFromDb'  => $this->totalFromDb,
+            'totalFromDb'  => $this->totalFromDb
         ];
     }
 }
diff --git a/library/Vspheredb/Util.php b/library/Vspheredb/Util.php
index efd25b39..2031f0ac 100644
--- a/library/Vspheredb/Util.php
+++ b/library/Vspheredb/Util.php
@@ -12,31 +12,31 @@ class Util
      *
      * @return int
      */
-    public static function currentTimestamp()
+    public static function currentTimestamp(): int
     {
         $time = explode(' ', microtime());
 
         return (int) round(1000 * ((int) $time[1] + (float) $time[0]));
     }
 
-    public static function timeStringToUnixTime($string)
+    public static function timeStringToUnixTime(string $string): int
     {
         return (new DateTime($string))->getTimestamp();
     }
 
-    public static function timeStringToUnixMs($string)
+    public static function timeStringToUnixMs(string $string): int
     {
-        $time = new DateTime($string);
-
-        return (int) (1000 * $time->format('U.u'));
+        return (int) (1000 * (new DateTime($string))->format('U.u'));
     }
 
     /**
      * DateTime for SOAP call
-     * @param $timestamp
+     *
+     * @param int $timestamp
+     *
      * @return string
      */
-    public static function makeDateTime($timestamp)
+    public static function makeDateTime(int $timestamp): string
     {
         return gmdate('Y-m-d\TH:i:s\Z', $timestamp);
     }
diff --git a/library/Vspheredb/VmwareDataType/ManagedObjectReference.php b/library/Vspheredb/VmwareDataType/ManagedObjectReference.php
index 68e9be95..b4583afa 100644
--- a/library/Vspheredb/VmwareDataType/ManagedObjectReference.php
+++ b/library/Vspheredb/VmwareDataType/ManagedObjectReference.php
@@ -3,37 +3,41 @@
 namespace Icinga\Module\Vspheredb\VmwareDataType;
 
 use gipfl\Json\JsonSerialization;
+use ReturnTypeWillChange;
 
 /**
  * #[AllowDynamicProperties]
  */
 class ManagedObjectReference implements JsonSerialization
 {
-    public $_; // phpcs:ignore
+    public string $_; // phpcs:ignore
 
-    public $type;
+    public string $type;
 
-    public function __construct($type, $moref)
+    public function __construct(string $type, string $moref)
     {
         $this->_ = $moref;
         $this->type = $type;
     }
 
-    public function getLogName()
+    public function getLogName(): string
     {
         return $this->type . '[' . $this->_ . ']';
     }
 
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    /**
+     * @return object
+     */
+    public function jsonSerialize(): object
     {
         return (object) [
             '_'    => $this->_,
-            'type' => $this->type,
+            'type' => $this->type
         ];
     }
 
-    public static function fromSerialization($any)
+    public static function fromSerialization($any): static
     {
         return new static($any->type, $any->_);
     }
diff --git a/library/Vspheredb/VmwareDataType/NumericRange.php b/library/Vspheredb/VmwareDataType/NumericRange.php
index 2e906a39..a98adc4c 100644
--- a/library/Vspheredb/VmwareDataType/NumericRange.php
+++ b/library/Vspheredb/VmwareDataType/NumericRange.php
@@ -8,5 +8,6 @@
 class NumericRange
 {
     public $start;
+
     public $end;
 }
diff --git a/library/Vspheredb/Web/Controller.php b/library/Vspheredb/Web/Controller.php
index 049e26a7..3324bbcb 100644
--- a/library/Vspheredb/Web/Controller.php
+++ b/library/Vspheredb/Web/Controller.php
@@ -9,22 +9,18 @@
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Util\Csp;
+use ipl\Html\Attributes;
 use Zend_Controller_Request_Abstract as ZfRequest;
 use Zend_Controller_Response_Abstract as ZfResponse;
 
 class Controller extends CompatController
 {
-    /** @var Db */
-    private $db;
+    private ?Db $db = null;
 
-    /** @var ?RestrictionHelper */
-    private $restrictionHelper;
+    private ?RestrictionHelper $restrictionHelper = null;
 
-    public function __construct(
-        ZfRequest $request,
-        ZfResponse $response,
-        array $invokeArgs = array()
-    ) {
+    public function __construct(ZfRequest $request, ZfResponse $response, array $invokeArgs = array())
+    {
         parent::__construct($request, $response, $invokeArgs);
 
         if (! $this->isXhr() && Config::app()->get('security', 'use_strict_csp', false)) {
@@ -32,17 +28,15 @@ public function __construct(
         }
     }
 
-    public function init()
+    public function init(): void
     {
         parent::init();
         if ($this->view->compact) {
-            $this->controls()->addAttributes([
-                'class' => 'show-compact'
-            ]);
+            $this->controls()->addAttributes(Attributes::create(['class' => 'show-compact']));
         }
     }
 
-    protected function db()
+    protected function db(): Db
     {
         if ($this->db === null) {
             try {
@@ -51,7 +45,7 @@ protected function db()
                 if (! $migrations->hasSchema()) {
                     $this->redirectToConfiguration();
                 }
-            } catch (Exception $e) {
+            } catch (Exception) {
                 $this->redirectToConfiguration();
             }
         }
@@ -61,21 +55,18 @@ protected function db()
 
     protected function getRestrictionHelper(): RestrictionHelper
     {
-        if ($this->restrictionHelper === null) {
-            $this->restrictionHelper = new RestrictionHelper($this->Auth(), $this->db());
-        }
-
-        return $this->restrictionHelper;
+        return $this->restrictionHelper ??= new RestrictionHelper($this->Auth(), $this->db());
     }
 
     protected function requireVCenter($paramName = 'vcenter'): VCenter
     {
         $vCenter = VCenter::loadWithUuid($this->params->getRequired($paramName), $this->db());
         $this->getRestrictionHelper()->assertAccessToVCenterUuidIsGranted($vCenter->get('instance_uuid'));
+
         return $vCenter;
     }
 
-    protected function redirectToConfiguration()
+    protected function redirectToConfiguration(): void
     {
         if (
             $this->getRequest()->getControllerName() !== 'configuration'
diff --git a/library/Vspheredb/Web/Controller/ObjectsController.php b/library/Vspheredb/Web/Controller/ObjectsController.php
index a1b122a8..9ef93236 100644
--- a/library/Vspheredb/Web/Controller/ObjectsController.php
+++ b/library/Vspheredb/Web/Controller/ObjectsController.php
@@ -13,6 +13,7 @@
 use Icinga\Module\Vspheredb\Web\Table\Objects\ObjectsTable;
 use Icinga\Module\Vspheredb\Web\Table\TableWithParentFilter;
 use Icinga\Module\Vspheredb\Web\Table\TableWithVCenterFilter;
+use Icinga\Web\Url as WebUrl;
 use ipl\Html\Html;
 use Ramsey\Uuid\Uuid;
 
@@ -20,13 +21,13 @@ class ObjectsController extends Controller
 {
     use RestApi;
 
-    protected $otherTabActions = [];
+    protected array $otherTabActions = [];
 
-    /** @var PathLookup */
-    protected $pathLookup;
-    protected $vCenterFilterForm;
+    protected ?PathLookup $pathLookup = null;
 
-    protected function linkBackToOverview($type)
+    protected ?FilterVCenterForm $vCenterFilterForm = null;
+
+    protected function linkBackToOverview($type): static
     {
         $this->actions()->add(
             Link::create(
@@ -43,7 +44,7 @@ protected function linkBackToOverview($type)
         return $this;
     }
 
-    protected function addTreeViewToggle()
+    protected function addTreeViewToggle(): void
     {
         if ($this->params->get('render') === 'tree') {
             $this->actions()->add(
@@ -66,12 +67,13 @@ protected function addTreeViewToggle()
         }
     }
 
-    protected function eventuallyFilterByParent(TableWithParentFilter $table, $url, $defaultTitle = null)
-    {
-        $parent = $this->params->get('parent');
-        if ($parent === null) {
-            $parent = $this->params->get('uuid');
-        }
+    protected function eventuallyFilterByParent(
+        TableWithParentFilter $table,
+        WebUrl|string $url,
+        ?string $defaultTitle = null
+    ): void {
+        $parent = $this->params->get('parent') ?? $this->params->get('uuid');
+
         if ($parent !== null) {
             $parent = Uuid::fromString($parent)->getBytes();
         }
@@ -79,11 +81,7 @@ protected function eventuallyFilterByParent(TableWithParentFilter $table, $url,
         if ($parent) {
             $lookup = $this->pathLookup();
             $name = $lookup->getObjectName($parent);
-            if ($name) {
-                $this->addTitle($name);
-            } else {
-                $this->addTitle($defaultTitle);
-            }
+            $this->addTitle($name ?: $defaultTitle);
             if ($this->params->get('showDescendants')) {
                 $uuids = $lookup->listFoldersBelongingTo($parent);
                 $table->filterParentUuids($uuids);
@@ -96,7 +94,7 @@ protected function eventuallyFilterByParent(TableWithParentFilter $table, $url,
         }
     }
 
-    protected function eventuallyFilterByVCenter(TableWithVCenterFilter $table)
+    protected function eventuallyFilterByVCenter(TableWithVCenterFilter $table): void
     {
         $this->getRestrictionHelper()->restrictTable($table);
         $this->getVCenterFilterForm();
@@ -119,7 +117,7 @@ protected function getVCenterFilterForm(): FilterVCenterForm
         return $this->vCenterFilterForm;
     }
 
-    protected function showTable(ObjectsTable $table, $url, $defaultTitle = null)
+    protected function showTable(ObjectsTable $table, WebUrl|string $url, ?string $defaultTitle = null): static
     {
         $this->eventuallyFilterByParent($table, $url, $defaultTitle);
         $this->eventuallyFilterByVCenter($table);
@@ -129,7 +127,7 @@ protected function showTable(ObjectsTable $table, $url, $defaultTitle = null)
         return $this;
     }
 
-    protected function renderTableWithCount(ObjectsTable $table, $title = null)
+    protected function renderTableWithCount(ObjectsTable $table, ?string $title = null): void
     {
         $total = count($table);
         $table->renderTo($this);
@@ -137,14 +135,14 @@ protected function renderTableWithCount(ObjectsTable $table, $title = null)
             return;
         }
         $found = count($table);
-        if ($total === $found) {
-            $this->content()->prepend(sprintf('%d %s', $total, $title));
-        } else {
-            $this->content()->prepend(sprintf('%d out of %d %s', $found, $total, $title));
-        }
+        $this->content()->prepend(
+            $total === $found
+                ? sprintf('%d %s', $total, $title)
+                : sprintf('%d out of %d %s', $found, $total, $title)
+        );
     }
 
-    protected function downloadTable(ObjectsTable $table, string $title)
+    protected function downloadTable(ObjectsTable $table, string $title): void
     {
         $this->eventuallyFilterByParent($table, Url::fromPath(''), $title);
         $this->eventuallyFilterByVCenter($table);
@@ -156,7 +154,7 @@ protected function downloadTable(ObjectsTable $table, string $title)
         $this->downloadJson($this->getResponse(), $rows, "$title.json");
     }
 
-    protected function sendExport($type)
+    protected function sendExport($type): void
     {
         $import = new ImportSource();
         $import->setSettings([
@@ -167,7 +165,7 @@ protected function sendExport($type)
         $this->downloadJson($this->getResponse(), $import->fetchData(), $type . 's.json');
     }
 
-    protected function addPathTo($parent, $url)
+    protected function addPathTo(string $parent, WebUrl|string $url): void
     {
         $lookup = $this->pathLookup();
         $path = Html::tag('span', ['class' => 'dc-path']);
@@ -180,14 +178,14 @@ protected function addPathTo($parent, $url)
             }
             $path->add(Link::create($name, $url, [
                 'parent'          => Util::niceUuid($uuid),
-                'showDescendants' => true,
+                'showDescendants' => true
             ]));
         }
 
         $this->content()->add($path);
     }
 
-    protected function handleTabs()
+    protected function handleTabs(): void
     {
         $action = $this->getRequest()->getControllerName();
         if (isset($this->otherTabActions[$action])) {
@@ -198,15 +196,15 @@ protected function handleTabs()
         $this->tabs()->add('vms', [
             'label'     => $this->translate('Virtual Machine'),
             'url'       => 'vspheredb/vms',
-            'urlParams' => $urlParams,
+            'urlParams' => $urlParams
         ])->add('hosts', [
             'label'     => $this->translate('Hosts'),
             'url'       => 'vspheredb/hosts',
-            'urlParams' => $urlParams,
+            'urlParams' => $urlParams
         ])->add('datastores', [
             'label'     => $this->translate('Datastores'),
             'url'       => 'vspheredb/datastores',
-            'urlParams' => $urlParams,
+            'urlParams' => $urlParams
         ])
         // ->add('switches', [
         //     'label'     => $this->translate('Switches'),
@@ -229,10 +227,6 @@ protected function getParentParamsToPreserve(): array
 
     protected function pathLookup(): PathLookup
     {
-        if ($this->pathLookup === null) {
-            $this->pathLookup = new PathLookup($this->db()->getDbAdapter());
-        }
-
-        return $this->pathLookup;
+        return $this->pathLookup ??= new PathLookup($this->db()->getDbAdapter());
     }
 }
diff --git a/library/Vspheredb/Web/Controller/RestApi.php b/library/Vspheredb/Web/Controller/RestApi.php
index ef9936c7..c37e9eda 100644
--- a/library/Vspheredb/Web/Controller/RestApi.php
+++ b/library/Vspheredb/Web/Controller/RestApi.php
@@ -10,7 +10,7 @@
 
 trait RestApi
 {
-    protected function downloadJson(Response $response, $object, $filename)
+    protected function downloadJson(Response $response, array|object $object, string $filename): void
     {
         if (!$this->hasPermission('vspheredb/export')) {
             $this->sendJsonError($this->getResponse(), 'vspheredb/export permissions required', 403);
@@ -22,7 +22,7 @@ protected function downloadJson(Response $response, $object, $filename)
         $this->sendJson($response, $object);
     }
 
-    protected function sendJson(Response $response, $object)
+    protected function sendJson(Response $response, array|object $object): void
     {
         $response->setHeader('Content-Type', 'application/json', true);
         $this->_helper->layout()->disableLayout();
@@ -37,13 +37,15 @@ protected function sendJson(Response $response, $object)
     /**
      * @param Response $response
      * @param string $message
-     * @param int|null $code
+     * @param ?int $code
+     *
+     * @return void
      */
-    protected function sendJsonError(Response $response, $message, $code = null)
+    protected function sendJsonError(Response $response, string $message, ?int $code = null): void
     {
         if ($code !== null) {
             try {
-                $response->setHttpResponseCode((int) $code);
+                $response->setHttpResponseCode($code);
             } catch (Zend_Controller_Response_Exception $e) {
                 throw new InvalidArgumentException($e->getMessage(), 0, $e);
             }
diff --git a/library/Vspheredb/Web/Form/ApplyMigrationsForm.php b/library/Vspheredb/Web/Form/ApplyMigrationsForm.php
index 3a6c40dd..1d40746f 100644
--- a/library/Vspheredb/Web/Form/ApplyMigrationsForm.php
+++ b/library/Vspheredb/Web/Form/ApplyMigrationsForm.php
@@ -12,40 +12,30 @@ class ApplyMigrationsForm extends Form
 {
     use Translation;
 
-    /** @var  Migrations */
-    protected $migrations;
+    protected Migrations $migrations;
 
     public function __construct(Migrations $migrations)
     {
         $this->migrations = $migrations;
     }
 
-    public function assemble()
+    protected function assemble(): void
     {
         if ($this->migrations->hasSchema()) {
             $count = $this->migrations->countPendingMigrations();
-            if ($count === 1) {
-                $label = $this->translate('Apply a pending schema migration');
-            } else {
-                $label = sprintf(
-                    $this->translate('Apply %d pending schema migrations'),
-                    $count
-                );
-            }
+            $label = $count === 1
+                ? $this->translate('Apply a pending schema migration')
+                : sprintf($this->translate('Apply %d pending schema migrations'), $count);
         } else {
             $this->add(Hint::warning($this->translate('There is no vSphereDB schema in this database')));
             $label = $this->translate('Create schema');
         }
-        $this->addElement('submit', 'submit', [
-            'label' => $label
-        ]);
+        $this->addElement('submit', 'submit', ['label' => $label]);
     }
 
-    public function onSuccess()
+    protected function onSuccess(): void
     {
         $this->migrations->applyPendingMigrations();
-        Notification::success($this->translate(
-            'Pending database schema migrations have successfully been applied'
-        ));
+        Notification::success($this->translate('Pending database schema migrations have successfully been applied'));
     }
 }
diff --git a/library/Vspheredb/Web/Form/ChooseDbResourceForm.php b/library/Vspheredb/Web/Form/ChooseDbResourceForm.php
index f041e736..76fd29a8 100644
--- a/library/Vspheredb/Web/Form/ChooseDbResourceForm.php
+++ b/library/Vspheredb/Web/Form/ChooseDbResourceForm.php
@@ -8,6 +8,7 @@
 use gipfl\Web\Form;
 use gipfl\Web\Widget\Hint;
 use Icinga\Application\Config;
+use Icinga\Data\Db\DbConnection;
 use Icinga\Data\ResourceFactory;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Web\Notification;
@@ -18,22 +19,22 @@ class ChooseDbResourceForm extends Form
 {
     use Translation;
 
-    private $config;
+    private ?Config $config = null;
 
-    private $storeConfigLabel;
+    private ?string $storeConfigLabel = null;
 
-    private $createDbLabel;
+    private ?string $createDbLabel = null;
 
-    private $migrateDbLabel;
+    private ?string $migrateDbLabel = null;
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->storeConfigLabel = $this->translate('Store configuration');
 
         $this->addResourceConfigElements();
 
         if (
-            !$this->config()->get('db', 'resource')
+            ! $this->config()->get('db', 'resource')
             || ($this->config()->get('db', 'resource') !== $this->getResourceName())
         ) {
             return;
@@ -57,8 +58,7 @@ protected function assemble()
                 $resource = $this->getResource();
                 $db = $resource->getDbAdapter();
             } catch (Exception $e) {
-                $this->getElement('resource')
-                    ->addMessage('Resource failed: ' . $e->getMessage());
+                $this->getElement('resource')->addMessage('Resource failed: ' . $e->getMessage());
 
                 return;
             }
@@ -66,8 +66,7 @@ protected function assemble()
             try {
                 $db->fetchOne('SELECT 1');
             } catch (Exception $e) {
-                $this->getElement('resource')
-                    ->addMessage('Could not connect to database: ' . $e->getMessage());
+                $this->getElement('resource')->addMessage('Could not connect to database: ' . $e->getMessage());
 
                 $this->add(Hint::info($this->translate(
                     'Please make sure that your database exists and your user has'
@@ -77,7 +76,7 @@ protected function assemble()
         }
     }
 
-    protected function addResourceConfigElements()
+    protected function addResourceConfigElements(): void
     {
         $config = $this->config();
         $resources = $this->enumResources();
@@ -90,7 +89,7 @@ protected function addResourceConfigElements()
             'value'         => $config->get('db', 'resource')
         ]);
 
-        if (!$this->getResourceName()) {
+        if (! $this->getResourceName()) {
             $this->add(Hint::info($this->translate(
                 'No database resource has been configured yet. Please choose a'
                 . ' resource to complete your config'
@@ -117,7 +116,7 @@ protected function addResourceConfigElements()
     /**
      * @return bool
      */
-    protected function storeResourceConfig()
+    protected function storeResourceConfig(): bool
     {
         $config = $this->config();
         $value = $this->getValue('resource');
@@ -130,7 +129,7 @@ protected function storeResourceConfig()
             Notification::success($this->translate('Configuration has been stored'));
 
             return true;
-        } catch (Exception $e) {
+        } catch (Exception) {
             $this->getElement('resource')->addMessage(
                 sprintf(
                     $this->translate(
@@ -156,7 +155,7 @@ protected function storeResourceConfig()
         }
     }
 
-    public function onSuccess()
+    protected function onSuccess(): void
     {
         if ($this->getSubmitLabel() === $this->storeConfigLabel) {
             if ($this->storeResourceConfig()) {
@@ -166,40 +165,37 @@ public function onSuccess()
             }
         }
 
-        if (
-            $this->getSubmitLabel() === $this->createDbLabel
-            || $this->getSubmitLabel() === $this->migrateDbLabel
-        ) {
+        if ($this->getSubmitLabel() === $this->createDbLabel || $this->getSubmitLabel() === $this->migrateDbLabel) {
             $this->migrations()->applyPendingMigrations();
         }
     }
 
-    protected function getSubmitLabel()
+    protected function getSubmitLabel(): string
     {
         return $this->getSubmitButton()->getButtonLabel();
     }
 
-    protected function getResourceName()
+    protected function getResourceName(): ?string
     {
         if ($this->hasBeenSent()) {
             $resource = $this->getValue('resource');
             $resources = $this->enumResources();
             if (in_array($resource, $resources)) {
                 return $resource;
-            } else {
-                return null;
             }
-        } else {
-            return $this->config()->get('db', 'resource');
+
+            return null;
         }
+
+        return $this->config()->get('db', 'resource');
     }
 
-    public function getDb()
+    public function getDb(): Db
     {
         return Db::fromResourceName($this->getResourceName());
     }
 
-    protected function getResource()
+    protected function getResource(): DbConnection
     {
         return ResourceFactory::create($this->getResourceName());
     }
@@ -207,28 +203,27 @@ protected function getResource()
     /**
      * @return Migrations
      */
-    protected function migrations()
+    protected function migrations(): Migrations
     {
         return Db::migrationsForDb($this->getDb());
     }
 
-    public function setModuleConfig(Config $config)
+    public function setModuleConfig(Config $config): static
     {
         $this->config = $config;
 
         return $this;
     }
 
-    protected function config()
+    protected function config(): Config
     {
-        if ($this->config === null) {
-            $this->config = Config::module('vspheredb');
-        }
-
-        return $this->config;
+        return $this->config ??= Config::module('vspheredb');
     }
 
-    protected function enumResources()
+    /**
+     * @return array<string, string>
+     */
+    protected function enumResources(): array
     {
         // return [];
         $resources = [];
diff --git a/library/Vspheredb/Web/Form/ChooseInfluxDatabaseForm.php b/library/Vspheredb/Web/Form/ChooseInfluxDatabaseForm.php
index 17d6c623..36bbc80c 100644
--- a/library/Vspheredb/Web/Form/ChooseInfluxDatabaseForm.php
+++ b/library/Vspheredb/Web/Form/ChooseInfluxDatabaseForm.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Web\Form;
 
+use Exception;
 use gipfl\Web\Form;
 use gipfl\Web\Form\Element\TextWithActionButton;
 use Icinga\Module\Vspheredb\Daemon\RemoteClient;
@@ -19,20 +20,13 @@ class ChooseInfluxDatabaseForm extends Form
 {
     use Translation;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
-    /** @var array|null|false */
-    protected $dbList;
+    protected array|null|false $dbList = null;
 
-    /**
-     * @var RemoteClient
-     */
-    protected $client;
-    /**
-     * @var PerfDataConsumerHook
-     */
-    protected $hook;
+    protected RemoteClient $client;
+
+    protected PerfDataConsumerHook $hook;
 
     public function __construct(LoopInterface $loop, RemoteClient $client, PerfDataConsumerHook $hook)
     {
@@ -41,22 +35,22 @@ public function __construct(LoopInterface $loop, RemoteClient $client, PerfDataC
         $this->hook = $hook;
     }
 
-    public function assemble()
+    protected function assemble(): void
     {
         $this->addDbSelection();
     }
 
-    protected function prepareParams()
+    protected function prepareParams(): array
     {
         return [
             'baseUrl'    => $this->hook->getSetting('base_url'),
             'apiVersion' => $this->hook->getSetting('api_version'),
             'username'   => $this->hook->getSetting('username'),
-            'password'   => $this->hook->getSetting('password'),
+            'password'   => $this->hook->getSetting('password')
         ];
     }
 
-    protected function getDbList()
+    protected function getDbList(): false|array|null
     {
         if ($this->dbList === null) {
             $this->refreshDbList();
@@ -65,39 +59,35 @@ protected function getDbList()
         return $this->dbList;
     }
 
-    protected function remoteRequest($request, $params = [])
+    protected function remoteRequest(string $request, ?array $params = []): mixed
     {
         return await(timeout($this->client->request($request, $params), 5, $this->loop));
     }
 
-    protected function refreshDbList()
+    protected function refreshDbList(): void
     {
         try {
-            $this->dbList = \array_filter(
+            $this->dbList = array_filter(
                 (array) $this->remoteRequest('influxdb.listDatabases', $this->prepareParams()),
-                function ($value) {
-                    return $value[0] !== '_';
-                }
+                fn ($value) => $value[0] !== '_'
             );
-        } catch (\Exception $e) {
+        } catch (Exception) {
             // Hint: we no longer refresh if it's false
             $this->dbList = false;
         }
     }
 
-    protected function createDatabase($name)
+    protected function createDatabase($name): mixed
     {
         Notification::info("Creating $name");
-        $promise = $this->client->request('influxdb.createDatabase', $this->prepareParams() + [
-            'dbName' => $name
-        ]);
+        $promise = $this->client->request('influxdb.createDatabase', $this->prepareParams() + ['dbName' => $name]);
         $result = await($promise);
         Notification::info("DON $name");
 
         return $result;
     }
 
-    protected function createRequestedDb(BaseFormElement $element, TextWithActionButton $action)
+    protected function createRequestedDb(BaseFormElement $element, TextWithActionButton $action): void
     {
         $name = $element->getValue();
         try {
@@ -109,7 +99,7 @@ protected function createRequestedDb(BaseFormElement $element, TextWithActionBut
             if ($element instanceof SelectElement) {
                 $element->setOptions($dbOptions);
             }
-            if (\in_array($name, $dbOptions)) {
+            if (in_array($name, $dbOptions)) {
                 $element->setValue($name);
             } else {
                 $this->triggerElementError(
@@ -118,19 +108,19 @@ protected function createRequestedDb(BaseFormElement $element, TextWithActionBut
                     $name
                 );
             }
-        } catch (\Exception $e) {
+        } catch (Exception $e) {
             $element->addMessage($e->getMessage());
         }
     }
 
-    protected function getDbOptions()
+    protected function getDbOptions(): array
     {
         return ['' => $this->translate('Please choose')]
-        + \array_combine($this->dbList, $this->dbList)
+        + array_combine($this->dbList, $this->dbList)
         + ['_new' => ' -> ' . $this->translate('Create a new Database')];
     }
 
-    protected function addDbSelection()
+    protected function addDbSelection(): static
     {
         if ($this->getSentValue('dbname') === '_new') {
             $elDbName = $this->createElement('hidden', 'dbname');
@@ -147,7 +137,7 @@ protected function addDbSelection()
         } else {
             $elDbName = $this->createElement('text', 'dbname', [
                 'label'       => $this->translate('Database'),
-                'required'    => true,
+                'required'    => true
             ]);
             $this->addElement($elDbName);
         }
@@ -155,7 +145,7 @@ protected function addDbSelection()
             $action = new TextWithActionButton('new_dbname', [
                 'label'       => $this->translate('New Database'),
                 'description' => $this->translate('New InfluxDB database name'),
-                'required'    => true,
+                'required'    => true
             ], [
                 'label' => $this->translate('Create'),
                 'title' => $this->translate('Create a new InfluxDB database')
diff --git a/library/Vspheredb/Web/Form/DeleteVCenterForm.php b/library/Vspheredb/Web/Form/DeleteVCenterForm.php
index b99f0b2a..9e1aec2d 100644
--- a/library/Vspheredb/Web/Form/DeleteVCenterForm.php
+++ b/library/Vspheredb/Web/Form/DeleteVCenterForm.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Web\Form;
 
+use Exception;
 use gipfl\Web\Form;
 use gipfl\Web\Form\Feature\NextConfirmCancel;
 use gipfl\Web\Widget\Hint;
@@ -11,7 +12,6 @@
 use Icinga\Web\Notification;
 use ipl\Html\Html;
 use ipl\I18n\Translation;
-use Ramsey\Uuid\Uuid;
 use React\EventLoop\LoopInterface;
 
 use function React\Async\await;
@@ -22,18 +22,13 @@ class DeleteVCenterForm extends Form
 
     protected $defaultDecoratorClass = null;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
-    /** @var RemoteClient */
-    protected $client;
+    protected RemoteClient $client;
 
-    /** @var LoopInterface */
-    protected $loop;
-    /**
-     * @var Db
-     */
-    protected $db;
+    protected LoopInterface $loop;
+
+    protected Db $db;
 
     public function __construct(Db $db, VCenter $vCenter, RemoteClient $client, LoopInterface $loop)
     {
@@ -43,7 +38,7 @@ public function __construct(Db $db, VCenter $vCenter, RemoteClient $client, Loop
         $this->loop = $loop;
     }
 
-    public function assemble()
+    protected function assemble(): void
     {
         $this->add(Html::tag('h3', $this->translate('Delete this vCenter')));
         $this->add(Hint::warning($this->translate(
@@ -62,19 +57,19 @@ public function assemble()
         ))->addToForm($this);
     }
 
-    public function onSuccess()
+    protected function onSuccess(): void
     {
         $db = $this->db->getDbAdapter();
         // Delete the connection first.
         $db->delete('vcenter_server', $db->quoteInto('vcenter_id = ?', (int) $this->vCenter->get('id')));
 
         try {
-            if (await($this->client->request('db.deleteVcenter', [$this->vCenter->get('id')]))) {
-                Notification::success($this->translate('vCenter data cleanup has been launched'));
-            } else {
-                Notification::success($this->translate('Failed to trigger vCenter data cleanup'));
-            }
-        } catch (\Exception $e) {
+            Notification::success(
+                await($this->client->request('db.deleteVcenter', [$this->vCenter->get('id')]))
+                    ? $this->translate('vCenter data cleanup has been launched')
+                    : $this->translate('Failed to trigger vCenter data cleanup')
+            );
+        } catch (Exception $e) {
             Notification::error($e->getMessage());
         }
     }
diff --git a/library/Vspheredb/Web/Form/DisableServerForm.php b/library/Vspheredb/Web/Form/DisableServerForm.php
index 8c32ff3e..f0cc4091 100644
--- a/library/Vspheredb/Web/Form/DisableServerForm.php
+++ b/library/Vspheredb/Web/Form/DisableServerForm.php
@@ -2,43 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Web\Form;
 
-use gipfl\Web\Form\Feature\NextConfirmCancel;
-use gipfl\Web\InlineForm;
-use ipl\I18n\Translation;
-
-class DisableServerForm extends InlineForm
+class DisableServerForm extends ServerActionForm
 {
-    use Translation;
-
-    protected $serverId;
-
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
-
-    public function __construct($serverId, $db)
-    {
-        $this->serverId = $serverId;
-        $this->db = $db;
-    }
-
-    public function getUniqueFormName()
-    {
-        return parent::getUniqueFormName() . '-' . $this->serverId;
-    }
-
-    protected function assemble()
-    {
-        (new NextConfirmCancel(
-            NextConfirmCancel::buttonNext($this->translate('Disable')),
-            NextConfirmCancel::buttonConfirm($this->translate('Really disable')),
-            NextConfirmCancel::buttonCancel($this->translate('Cancel'))
-        ))->addToForm($this);
-    }
-
-    public function onSuccess()
-    {
-        $this->db->update('vcenter_server', [
-            'enabled' => 'n'
-        ], $this->db->quoteInto('id = ?', $this->serverId));
-    }
+    protected ?string $serverAction = 'disable';
 }
diff --git a/library/Vspheredb/Web/Form/Element/VCenterSelection.php b/library/Vspheredb/Web/Form/Element/VCenterSelection.php
index 50e73fd7..b580e9ff 100644
--- a/library/Vspheredb/Web/Form/Element/VCenterSelection.php
+++ b/library/Vspheredb/Web/Form/Element/VCenterSelection.php
@@ -5,6 +5,7 @@
 use Icinga\Authentication\Auth;
 use Icinga\Module\Vspheredb\Auth\RestrictionHelper;
 use Icinga\Module\Vspheredb\Db;
+use ipl\Html\Attributes;
 use ipl\Html\FormElement\SelectElement;
 use ipl\I18n\Translation;
 use Ramsey\Uuid\Uuid;
@@ -13,13 +14,11 @@ class VCenterSelection extends SelectElement
 {
     use Translation;
 
-    /** @var Db */
-    protected $connection;
+    protected Db $connection;
 
-    /** @var Auth */
-    protected $auth;
+    protected Auth $auth;
 
-    protected $optional = false;
+    protected bool $optional = false;
 
     public function __construct(Db $connection, Auth $auth, $required = false, $name = 'vcenter', $attributes = null)
     {
@@ -27,19 +26,19 @@ public function __construct(Db $connection, Auth $auth, $required = false, $name
         $this->auth = $auth;
         parent::__construct($name, $attributes);
         $enum = $this->enumVCenters();
-        $this->addAttributes([
-            'options' => $required ? $enum : ['' => $this->translate('All vCenters'),] + $enum,
-            'class' => 'autosubmit',
-        ]);
+        $this->addAttributes(Attributes::create([
+            'options' => $required ? $enum : ['' => $this->translate('All vCenters')] + $enum,
+            'class' => 'autosubmit'
+        ]));
     }
 
-    protected function enumVCenters()
+    protected function enumVCenters(): array
     {
         $db = $this->connection->getDbAdapter();
         $pairs = $db->fetchPairs(
             $db->select()->from(['vc' => 'vcenter'], [
                 'uuid' => 'LOWER(HEX(vc.instance_uuid))',
-                'name' => "vc.name || ' (' || REPLACE(vc.api_name, 'VMware ', '') || ')'",
+                'name' => "vc.name || ' (' || REPLACE(vc.api_name, 'VMware ', '') || ')'"
             ])->order('vc.name')
         );
         $enum = [];
diff --git a/library/Vspheredb/Web/Form/EnableServerForm.php b/library/Vspheredb/Web/Form/EnableServerForm.php
index 39b8e28e..a789134b 100644
--- a/library/Vspheredb/Web/Form/EnableServerForm.php
+++ b/library/Vspheredb/Web/Form/EnableServerForm.php
@@ -2,43 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Web\Form;
 
-use gipfl\Web\Form\Feature\NextConfirmCancel;
-use gipfl\Web\InlineForm;
-use ipl\I18n\Translation;
-
-class EnableServerForm extends InlineForm
+class EnableServerForm extends ServerActionForm
 {
-    use Translation;
-
-    protected $serverId;
-
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
-
-    public function __construct($serverId, $db)
-    {
-        $this->serverId = $serverId;
-        $this->db = $db;
-    }
-
-    public function getUniqueFormName()
-    {
-        return parent::getUniqueFormName() . '-' . $this->serverId;
-    }
-
-    protected function assemble()
-    {
-        (new NextConfirmCancel(
-            NextConfirmCancel::buttonNext($this->translate('Enable')),
-            NextConfirmCancel::buttonConfirm($this->translate('Really enable')),
-            NextConfirmCancel::buttonCancel($this->translate('Cancel'))
-        ))->addToForm($this);
-    }
-
-    public function onSuccess()
-    {
-        $this->db->update('vcenter_server', [
-            'enabled' => 'y'
-        ], $this->db->quoteInto('id = ?', $this->serverId));
-    }
+    protected ?string $serverAction = 'enable';
 }
diff --git a/library/Vspheredb/Web/Form/FilterHostParentForm.php b/library/Vspheredb/Web/Form/FilterHostParentForm.php
index 5da1edd7..62917075 100644
--- a/library/Vspheredb/Web/Form/FilterHostParentForm.php
+++ b/library/Vspheredb/Web/Form/FilterHostParentForm.php
@@ -6,28 +6,31 @@
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\Util;
 use ipl\I18n\Translation;
+use Zend_Db_Adapter_Abstract;
 
 class FilterHostParentForm extends Form
 {
     use Translation;
 
+    protected $method = 'GET';
+
     protected $useFormName = false;
+
     protected $useCsrf = false;
 
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
 
     public function __construct(Db $connection)
     {
         $this->db = $connection->getDbAdapter();
-        $this->setMethod('GET');
     }
 
-    public function hasDefaultElementDecorator()
+    public function hasDefaultElementDecorator(): false
     {
         return false;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $vMotionEvents = [
             // 'MigrationEvent',
@@ -35,7 +38,7 @@ protected function assemble()
             'VmBeingHotMigratedEvent',
             'VmEmigratingEvent',
             'VmMigratedEvent',
-            'VmFailedMigrateEvent',
+            'VmFailedMigrateEvent'
         ];
 
         $otherKnownEvents = [
@@ -56,11 +59,10 @@ protected function assemble()
         ];
 
         $this->addElement('select', 'type', [
-            'options' => [
-                '' => $this->translate('- filter by event type -')
-            ] + array_combine($vMotionEvents, $vMotionEvents)
+            'options' => ['' => $this->translate('- filter by event type -')]
+                + array_combine($vMotionEvents, $vMotionEvents)
                 + array_combine($otherKnownEvents, $otherKnownEvents),
-            'class' => 'autosubmit',
+            'class' => 'autosubmit'
         ]);
         $parents = $this->enumHostParents();
         if (empty($parents)) {
@@ -70,46 +72,38 @@ protected function assemble()
         } else {
             $this->addElement('select', 'parent', [
                 'options' => ['' => $this->translate('- filter by parent -')] + $parents,
-                'class' => 'autosubmit',
+                'class' => 'autosubmit'
             ]);
         }
     }
 
-    public function onSuccess()
+    protected function onSuccess(): void
     {
         // Overriding ipl method, would otherwise render a "success" paragraph
     }
 
     public function getColors(): array
     {
-        $colors = [
-            'VmPoweredOffEvent' => [255, 0, 0],
-            'VmResettingEvent' => [164, 0, 0],
-            'VmBeingHotMigratedEvent' => [255, 164, 0],
-            'VmReconfiguredEvent' => [164, 0, 128],
-            'VmPoweredOnEvent' => [0, 164, 0],
-            'VmCreatedEvent' => [0, 164, 0],
-            'VmStartingEvent' => [119, 170, 255],
-            'VmBeingCreatedEvent' => [119, 170, 255],
-        ];
-
-        $type = $this->getElement('type')->getValue() ?? '';
-
-        return $colors[$type] ?? $colors['VmReconfiguredEvent'];
+        return match ($this->getElement('type')->getValue()) {
+            'VmPoweredOffEvent'                      => [255, 0, 0],
+            'VmResettingEvent'                       => [164, 0, 0],
+            'VmBeingHotMigratedEvent'                => [255, 164, 0],
+            'VmPoweredOnEvent', 'VmCreatedEvent'     => [0, 164, 0],
+            'VmStartingEvent', 'VmBeingCreatedEvent' => [119, 170, 255],
+            default                                  => [164, 0, 128], // Use VmReconfiguredEvent as fallback
+        };
     }
 
-    protected function enumHostParents()
+    protected function enumHostParents(): array
     {
         $db = $this->db;
-        $query = $db->select()->from(
-            ['p' => 'object'],
-            ['p.uuid', 'p.object_name']
-        )->join(
+        $query = $db->select()->from(['p' => 'object'], ['p.uuid', 'p.object_name'])->join(
             ['c' => 'object'],
-            'c.parent_uuid = p.uuid AND '
-            . $db->quoteInto('c.object_type = ?', 'HostSystem')
-            . ' AND '
-            . $db->quoteInto('p.object_type = ?', 'ClusterComputeResource'),
+            sprintf(
+                'c.parent_uuid = p.uuid AND %s AND %s',
+                $db->quoteInto('c.object_type = ?', 'HostSystem'),
+                $db->quoteInto('p.object_type = ?', 'ClusterComputeResource')
+            ),
             []
         )->group('p.uuid')->order('p.object_name');
 
diff --git a/library/Vspheredb/Web/Form/FilterVCenterForm.php b/library/Vspheredb/Web/Form/FilterVCenterForm.php
index 8513057e..fabcf98a 100644
--- a/library/Vspheredb/Web/Form/FilterVCenterForm.php
+++ b/library/Vspheredb/Web/Form/FilterVCenterForm.php
@@ -7,45 +7,48 @@
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\Web\Form\Element\VCenterSelection;
 use ipl\I18n\Translation;
+use Zend_Db_Adapter_Abstract;
 
 class FilterVCenterForm extends Form
 {
     use Translation;
 
-    /** @var Auth */
-    protected $auth;
+    protected $method = 'GET';
 
-    /** @var Db */
-    protected $connection;
+    protected Auth $auth;
 
-    /** @var \Zend_Db_Adapter_Abstract  */
-    protected $db;
+    protected Db $connection;
+
+    protected Zend_Db_Adapter_Abstract $db;
 
     protected $useFormName = false;
+
     protected $defaultDecoratorClass = null;
+
     protected $useCsrf = false;
-    protected $allowAllVCenters = false;
+
+    protected bool $allowAllVCenters = false;
 
     public function __construct(Db $connection, Auth $auth)
     {
         $this->db = $connection->getDbAdapter();
-        $this->setMethod('GET');
         $this->auth = $auth;
         $this->connection = $connection;
     }
 
-    public function allowAllVCenters($allow = true): self
+    public function allowAllVCenters(bool $allow = true): static
     {
         $this->allowAllVCenters = $allow;
+
         return $this;
     }
 
-    public function getHexUuid()
+    public function getHexUuid(): string
     {
         return $this->getElement('vcenter')->getValue();
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->addElement(new VCenterSelection($this->connection, $this->auth, !$this->allowAllVCenters));
     }
diff --git a/library/Vspheredb/Web/Form/FormElementStealer.php b/library/Vspheredb/Web/Form/FormElementStealer.php
index 7a4d14e9..cf2d7336 100644
--- a/library/Vspheredb/Web/Form/FormElementStealer.php
+++ b/library/Vspheredb/Web/Form/FormElementStealer.php
@@ -9,14 +9,12 @@
 
 trait FormElementStealer
 {
-    protected $mainProperties = [];
+    protected array $mainProperties = [];
 
-    public function getValues()
+    public function getValues(): array
     {
         $values = parent::getValues();
-        $mainProperties = array_merge($this->mainProperties, [
-            'settings',
-        ]);
+        $mainProperties = array_merge($this->mainProperties, ['settings']);
         $finalValues = [];
         $settings = [];
         foreach ($values as $key => $value) {
@@ -31,7 +29,7 @@ public function getValues()
         return $finalValues;
     }
 
-    protected function addButtons($final, $selectProperty)
+    protected function addButtons(bool $final, string $selectProperty): void
     {
         if ($final) {
             $submit = new SubmitElement('submit', [
@@ -45,7 +43,7 @@ protected function addButtons($final, $selectProperty)
             if ($this->isNew()) {
                 $back = new SubmitElement('btn_back', [
                     'label' => $this->translate('Back'),
-                    'formnovalidate' => true,
+                    'formnovalidate' => true
                 ]);
                 $deco->dd()->add($back);
                 $this->registerElement($back);
@@ -53,9 +51,7 @@ protected function addButtons($final, $selectProperty)
                     $this->setElementValue($selectProperty, null);
                 }
             } else {
-                $delete = new SubmitElement('btn_delete', [
-                    'label' => $this->translate('Delete')
-                ]);
+                $delete = new SubmitElement('btn_delete', ['label' => $this->translate('Delete')]);
                 $deco->dd()->add($delete);
                 $this->registerElement($delete);
                 if ($delete->hasBeenPressed()) {
@@ -64,13 +60,11 @@ protected function addButtons($final, $selectProperty)
                 }
             }
         } else {
-            $this->addElement('submit', 'next', [
-                'label' => $this->translate('Next')
-            ]);
+            $this->addElement('submit', 'next', ['label' => $this->translate('Next')]);
         }
     }
 
-    protected function addFormElementsFrom(Form $form)
+    protected function addFormElementsFrom(Form $form): void
     {
         foreach ($this->getElements() as $mainElement) {
             if (! $mainElement->isIgnored()) {
diff --git a/library/Vspheredb/Web/Form/InfluxDbConnectionForm.php b/library/Vspheredb/Web/Form/InfluxDbConnectionForm.php
index b002f61c..e8fe8e57 100644
--- a/library/Vspheredb/Web/Form/InfluxDbConnectionForm.php
+++ b/library/Vspheredb/Web/Form/InfluxDbConnectionForm.php
@@ -2,9 +2,11 @@
 
 namespace Icinga\Module\Vspheredb\Web\Form;
 
+use Exception;
 use gipfl\Web\Form;
 use gipfl\Web\Form\Element\TextWithActionButton;
 use Icinga\Module\Vspheredb\Daemon\RemoteClient;
+use ipl\Html\Attributes;
 use ipl\Html\FormElement\SelectElement;
 use ipl\I18n\Translation;
 use React\EventLoop\LoopInterface;
@@ -18,20 +20,17 @@ class InfluxDbConnectionForm extends Form
 
     public const INFLUXDB_MIN_SUPPORTED_VERSION = '1.6.0';
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
-    protected $detectedApiVersion;
+    protected ?string $detectedApiVersion = null;
 
-    protected $influxDbVersion;
+    protected ?string $influxDbVersion = null;
 
-    protected $baseUrlElement;
-    /**
-     * @var RemoteClient
-     */
-    protected $client;
+    protected ?TextWithActionButton $baseUrlElement = null;
+
+    protected RemoteClient $client;
 
-    protected $checkedNow = false;
+    protected bool $checkedNow = false;
 
     public function __construct(LoopInterface $loop, RemoteClient $client)
     {
@@ -39,14 +38,14 @@ public function __construct(LoopInterface $loop, RemoteClient $client)
         $this->client = $client;
     }
 
-    public function assemble()
+    protected function assemble(): void
     {
         $this->addHidden('checked_url', ['ignore' => true]);
         $this->addHidden('checked_api_version', ['ignore' => true]);
         $this->baseUrlElement = new TextWithActionButton('base_url', [
             'label'       => $this->translate('Base URL'),
             'description' => $this->translate('InfluxDB base URL, like http://influxdb.example.com:8086'),
-            'required'    => true,
+            'required'    => true
         ], [
             'label' => $this->translate('Verify'),
             'title' => $this->translate('Attempt to establish a connection to your InfluxDB instance')
@@ -55,20 +54,18 @@ public function assemble()
         $this->addElement('select', 'api_version', [
             'label' => $this->translate('API Version'),
             'class' => 'autosubmit',
-            'description' => $this->translate(
-                'InfluxDB API version, autodetect should work fine'
-            ),
+            'description' => $this->translate('InfluxDB API version, autodetect should work fine'),
             'options' => [
                 '' => $this->translate('Autodetect'),
                 'v1' => 'v1',
-                'v2' => 'v2',
-            ],
+                'v2' => 'v2'
+            ]
         ]);
         $this->appendVersionInformation($this->getDetectedApiVersion(), $this->getInfluxDbVersion());
         $this->addCredentials();
     }
 
-    protected function addCredentials()
+    protected function addCredentials(): static
     {
         if ($this->getApiVersion() === 'v2') {
             $this->addV2Credentials();
@@ -80,9 +77,9 @@ protected function addCredentials()
         return $this;
     }
 
-    protected function validateCredentials()
+    protected function validateCredentials(): void
     {
-        if (!$this->checkedNow) {
+        if (! $this->checkedNow) {
             return;
         }
         $username = $this->getValue('username');
@@ -100,38 +97,32 @@ protected function validateCredentials()
             ) {
                 $this->getElement('password')->getAttributes()->add('class', 'validated');
             }
-        } catch (\Exception $e) {
+        } catch (Exception $e) {
             $this->getElement('password')->addMessage($this->getExceptionMessageWithoutPhpFile($e));
         }
     }
 
-    protected function getExceptionMessageWithoutPhpFile(\Exception $e)
+    protected function getExceptionMessageWithoutPhpFile(Exception $e): string
     {
         return preg_replace('/\sin\s.+?\.php\(\d+\)/', '', $e->getMessage());
     }
 
-    protected function remoteRequest($request, $params = [])
+    protected function remoteRequest(string $request, array $params = []): mixed
     {
         return await(timeout($this->client->request($request, $params), 5, $this->loop));
     }
 
-    protected function getDetectedApiVersion()
+    protected function getDetectedApiVersion(): ?string
     {
-        if ($this->detectedApiVersion === null) {
-            $this->detectedApiVersion = $this->getApiVersionForVersionString(
-                $this->getInfluxDbVersion()
-            );
-        }
-
-        return $this->detectedApiVersion;
+        return $this->detectedApiVersion ??= $this->getApiVersionForVersionString($this->getInfluxDbVersion());
     }
 
-    protected function getApiVersion()
+    protected function getApiVersion(): string
     {
         return $this->getValue('api_version', $this->getDetectedApiVersion());
     }
 
-    protected function getInfluxDbVersion()
+    protected function getInfluxDbVersion(): ?string
     {
         if ($this->influxDbVersion === null) {
             $element = $this->getUrlElement();
@@ -147,31 +138,28 @@ protected function getInfluxDbVersion()
     }
 
     /**
-     * @return TextWithActionButton
+     * @return ?TextWithActionButton
      */
-    protected function getUrlElement()
+    protected function getUrlElement(): ?TextWithActionButton
     {
         return $this->baseUrlElement;
     }
 
-    protected function markUrlAsValidated()
+    protected function markUrlAsValidated(): static
     {
-        $this
-            ->getUrlElement()
-            ->getElement()
-            ->addAttributes(['class' => 'validated']);
+        $this->getUrlElement()->getElement()->addAttributes(Attributes::create(['class' => 'validated']));
 
         return $this;
     }
 
-    protected function autodetectIsUpToDate()
+    protected function autodetectIsUpToDate(): bool
     {
         $baseUrl = $this->getValue('base_url');
 
         return $baseUrl && $this->getValue('checked_url') === $baseUrl;
     }
 
-    protected function appendVersionInformation($apiVersion, $detectedVersion)
+    protected function appendVersionInformation(?string $apiVersion, ?string $detectedVersion): void
     {
         if (empty($apiVersion) || empty($detectedVersion)) {
             return;
@@ -179,95 +167,87 @@ protected function appendVersionInformation($apiVersion, $detectedVersion)
         $element = $this->getElement('api_version');
         assert($element instanceof SelectElement);
         $autoOption = $element->getOption('');
-        $autoOption->setLabel(\sprintf(
-            $this->translate('Autodetect: %s API, Version is %s'),
-            $apiVersion,
-            $detectedVersion
-        ));
+        $autoOption->setLabel(
+            sprintf($this->translate('Autodetect: %s API, Version is %s'), $apiVersion, $detectedVersion)
+        );
         $selectedOption = $element->getOption($apiVersion);
-        $selectedOption->setLabel(\sprintf(
-            $this->translate('%s (detected %s)'),
-            $apiVersion,
-            $detectedVersion
-        ));
+        $selectedOption->setLabel(sprintf($this->translate('%s (detected %s)'), $apiVersion, $detectedVersion));
         // $element->setValue($apiVersion);
     }
 
-    protected function addV1Credentials()
+    protected function addV1Credentials(): void
     {
-        $this->addElement('text', 'username', [
-            'label'       => $this->translate('Username'),
-        ]);
+        $this->addElement('text', 'username', ['label' => $this->translate('Username')]);
         $this->addElement('password', 'password', [
-            'label'       => $this->translate('Password'),
-            'required'    => $this->hasElementValue('username'),
+            'label'    => $this->translate('Password'),
+            'required' => $this->hasElementValue('username')
         ]);
     }
 
-    protected function addV2Credentials()
+    protected function addV2Credentials(): void
     {
         $this->addElement('text', 'username', [
-            'label'       => $this->translate('Organisation'),
-            'required'    => true,
+            'label'    => $this->translate('Organisation'),
+            'required' => true
         ]);
         $this->addElement('text', 'password', [
-            'label'       => $this->translate('Token'),
+            'label'    => $this->translate('Token'),
             // 'description' => $this->translate('InfluxDB Token (InfluxDB -> Data -> Tokens'),
-            'required'    => true,
+            'required' => true
         ]);
     }
 
-    protected function detectInfluxDbVersion($baseUrl)
+    protected function detectInfluxDbVersion($baseUrl): false|string|null
     {
         if ($this->getValue('base_url') === null) {
             return null;
         }
         try {
-            $version = $this->remoteRequest('influxdb.discoverVersion', [
-                'baseUrl' => $baseUrl,
-            ]);
+            $version = $this->remoteRequest('influxdb.discoverVersion', ['baseUrl' => $baseUrl]);
             $version = ltrim($version, 'v');
             if ($this->versionIsFine($version)) {
                 $this->checkedNow = true;
                 $this->setCheckedApiVersionFor($baseUrl, $version);
                 $this->markUrlAsValidated();
+
                 return $version;
-            } else {
-                throw new \Exception("Version $version is not supported");
             }
-        } catch (\Exception $e) {
+
+            throw new Exception("Version $version is not supported");
+        } catch (Exception $e) {
             $this->triggerElementError('base_url', $e->getMessage());
+
             return false;
         }
     }
 
-    protected function tryCredentials($baseUrl, $apiVersion, $username, $password)
+    protected function tryCredentials(string $baseUrl, string $apiVersion, string $username, string $password): mixed
     {
         return $this->remoteRequest('influxdb.testConnection', [
-            'baseUrl'  => $baseUrl,
+            'baseUrl'    => $baseUrl,
             'apiVersion' => $apiVersion,
-            'username' => $username,
-            'password' => $password,
+            'username'   => $username,
+            'password'   => $password
         ]);
     }
 
-    protected function setCheckedApiVersionFor($baseUrl, $version)
+    protected function setCheckedApiVersionFor(string $baseUrl, string $version): void
     {
         $this->getElement('checked_url')->setValue($baseUrl);
         $this->setElementValue('checked_api_version', $version);
     }
 
-    protected function versionIsFine($version)
+    protected function versionIsFine(string $version): bool
     {
-        return \version_compare($version, static::INFLUXDB_MIN_SUPPORTED_VERSION, 'ge');
+        return version_compare($version, static::INFLUXDB_MIN_SUPPORTED_VERSION, 'ge');
     }
 
-    protected function getApiVersionForVersionString($version)
+    protected function getApiVersionForVersionString(?string $version): ?string
     {
         if ($version === null) {
             return null;
         }
 
-        return \version_compare($version, '1.999.999', 'gt') ? 'v2' : 'v1';
+        return version_compare($version, '1.999.999', 'gt') ? 'v2' : 'v1';
     }
 }
diff --git a/library/Vspheredb/Web/Form/LogLevelForm.php b/library/Vspheredb/Web/Form/LogLevelForm.php
index 2c77ad21..dfcf489b 100644
--- a/library/Vspheredb/Web/Form/LogLevelForm.php
+++ b/library/Vspheredb/Web/Form/LogLevelForm.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Web\Form;
 
+use Exception;
 use gipfl\Web\Form\Feature\NextConfirmCancel;
 use gipfl\Web\InlineForm;
 use Icinga\Module\Vspheredb\Daemon\RemoteClient;
@@ -16,14 +17,11 @@ class LogLevelForm extends InlineForm
 {
     use Translation;
 
-    /** @var RemoteClient */
-    protected $client;
+    protected RemoteClient $client;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
-    /** @var boolean */
-    protected $talkedToSocket;
+    protected ?bool $talkedToSocket = null;
 
     public function __construct(RemoteClient $client, LoopInterface $loop)
     {
@@ -31,18 +29,19 @@ public function __construct(RemoteClient $client, LoopInterface $loop)
         $this->loop = $loop;
     }
 
-    public function talkedToSocket()
+    public function talkedToSocket(): ?bool
     {
         return $this->talkedToSocket;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         try {
             $currentLevel = await($this->client->request('logger.getLogLevel'));
             $this->talkedToSocket = true;
-        } catch (\Exception $e) {
+        } catch (Exception) {
             $this->talkedToSocket = false;
+
             return;
         }
 
@@ -56,17 +55,17 @@ protected function assemble()
         $toggle->showWithConfirm(new SelectElement('log_level', [
             'options'  => ['' => $this->translate('- please choose -')] + $this->listLogLevels(),
             'required' => true,
-            'value'    => $currentLevel,
+            'value'    => $currentLevel
         ]));
         $toggle->addToForm($this);
     }
 
-    protected function onSuccess()
+    protected function onSuccess(): void
     {
         await($this->client->request('logger.setLogLevel', ['level' => $this->getValue('log_level')]));
     }
 
-    protected function listLogLevels()
+    protected function listLogLevels(): array
     {
         $levels = [
             LogLevel::EMERGENCY,
@@ -76,7 +75,7 @@ protected function listLogLevels()
             LogLevel::WARNING,
             LogLevel::NOTICE,
             LogLevel::INFO,
-            LogLevel::DEBUG,
+            LogLevel::DEBUG
         ];
 
         return array_combine($levels, $levels);
diff --git a/library/Vspheredb/Web/Form/MonitoringConnectionForm.php b/library/Vspheredb/Web/Form/MonitoringConnectionForm.php
index 65c65211..2964b34e 100644
--- a/library/Vspheredb/Web/Form/MonitoringConnectionForm.php
+++ b/library/Vspheredb/Web/Form/MonitoringConnectionForm.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Vspheredb\Web\Form;
 
+use Exception;
+use gipfl\Web\Form;
 use gipfl\Web\Form\Decorator\DdDtDecorator;
 use gipfl\Web\Widget\Hint;
 use Icinga\Application\Config;
@@ -11,18 +13,20 @@
 use Icinga\Module\Vspheredb\Web\QueryParams;
 use Icinga\Web\Notification;
 use InvalidArgumentException;
-use ipl\I18n\Translation;
-use gipfl\Web\Form;
 use ipl\Html\FormElement\SubmitElement;
 use ipl\Html\Html;
+use ipl\I18n\Translation;
 use Ramsey\Uuid\Uuid;
+use Zend_Db_Adapter_Abstract;
 
 class MonitoringConnectionForm extends Form
 {
     use Translation;
 
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
+
     protected bool $hasBeenDeleted = false;
+
     protected ?int $id = null;
 
     public function __construct(Db $connection)
@@ -36,7 +40,7 @@ public function hasBeenDeleted(): bool
         return $this->hasBeenDeleted;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->add(Hint::info($this->translate(
             'The vSphereDB module can hook into the Icinga monitoring module.'
@@ -47,7 +51,7 @@ protected function assemble()
         $this->addElement('select', 'vcenter', [
             'label'    => $this->translate('vCenter'),
             'options'  => $this->optionalEnum($this->enumVCenters()),
-            'ignore'   => true,
+            'ignore'   => true
         ]);
 
         $this->addElement('select', 'source_type', [
@@ -57,7 +61,7 @@ protected function assemble()
                 // 'icinga2-api' => $this->translate('Icinga 2 API'),
                 'icingadb' => $this->translate('Icinga DB')
             ]),
-            'class' => 'autosubmit',
+            'class' => 'autosubmit'
         ]);
         $sourceType = $this->getElement('source_type')->getValue();
         if (! $sourceType) {
@@ -82,6 +86,7 @@ protected function assemble()
             $this->addElement('submit', 'submit', [
                 'label' => $this->translate('Next')
             ]);
+
             return;
         }
 
@@ -94,8 +99,9 @@ protected function assemble()
                 } else {
                     throw new InvalidArgumentException("Resource '$resourceName' is not a DbConnection");
                 }
-            } catch (\Exception $e) {
+            } catch (Exception $e) {
                 $this->getElement('source_resource_name')->addMessage($e->getMessage());
+
                 return;
             }
 
@@ -103,7 +109,7 @@ protected function assemble()
                 'name'         => $this->translate('Hostname'),
                 'display_name' => $this->translate('Display Name'),
                 'address'      => $this->translate('Address v4'),
-                'address6'     => $this->translate('Address v6'),
+                'address6'     => $this->translate('Address v6')
             ] + [$this->translate('Custom Variables') => $icingadbVars]);
         } else {
             try {
@@ -113,85 +119,69 @@ protected function assemble()
                 } else {
                     throw new InvalidArgumentException("Resource '$resourceName' is not a DbConnection");
                 }
-            } catch (\Exception $e) {
+            } catch (Exception $e) {
                 $this->getElement('source_resource_name')->addMessage($e->getMessage());
+
                 return;
             }
 
             $varOptions = $this->optionalEnum([
                 'host_name'    => $this->translate('Hostname'),
                 'display_name' => $this->translate('Display Name'),
-                'address'      => $this->translate('Address'),
+                'address'      => $this->translate('Address')
             ] + [$this->translate('Custom Variables') => $idoVars]);
         }
 
         $this->add(Html::tag('h2', $this->translate('Host Systems')));
         $this->add(Html::tag('p', $this->translate(
-            'Map monitored hosts to physical Host Systems belonging to your'
-            . ' VMware environment'
+            'Map monitored hosts to physical Host Systems belonging to your VMware environment'
         )));
         $this->addElement('select', 'host_property', [
             'label'       => $this->translate('Host System Property'),
-            'description' => $this->translate(
-                'Property of the Host System (known by the vSphereDB module)'
-            ),
+            'description' => $this->translate('Property of the Host System (known by the vSphereDB module)'),
             'options'     => $this->optionalEnum([
                 'host_name'    => $this->translate('Hostname'),
                 'object_name'  => $this->translate('Object Name'),
                 'sysinfo_uuid' => $this->translate('System (BIOS) UUID'),
-                'service_tag'  => $this->translate('IP Address'),
-            ]),
+                'service_tag'  => $this->translate('IP Address')
+            ])
         ]);
         $this->addElement('select', 'monitoring_host_property', [
             'label'       => $this->translate('Monitored Host Property'),
-            'description' => $this->translate(
-                'Property of the Host System (as known by Icinga)'
-            ),
-            'options'     => $varOptions,
+            'description' => $this->translate('Property of the Host System (as known by Icinga)'),
+            'options'     => $varOptions
         ]);
 
         $this->add(Html::tag('h2', $this->translate('Virtual Machines')));
         $this->add(Html::tag('p', $this->translate(
-            'Map monitored hosts to Virtual Machines belonging to your'
-            . ' VMware environment'
+            'Map monitored hosts to Virtual Machines belonging to your VMware environment'
         )));
         $this->addElement('select', 'vm_property', [
             'label'       => $this->translate('Virtual Machine Property'),
-            'description' => $this->translate(
-                'Property of the Virtual Machine (known by the vSphereDB module)'
-            ),
+            'description' => $this->translate('Property of the Virtual Machine (known by the vSphereDB module)'),
             'options'     => $this->optionalEnum([
                 'guest_host_name' => $this->translate('Guest Hostname'),
                 'object_name'     => $this->translate('Object Name'),
-                'bios_uuid'       => $this->translate('BIOS UUID'),
-            ]),
+                'bios_uuid'       => $this->translate('BIOS UUID')
+            ])
         ]);
         $this->addElement('select', 'monitoring_vm_host_property', [
             'label'       => $this->translate('Monitored Host Property'),
-            'description' => $this->translate(
-                'Property of the Virtual Machine (as known by Icinga)'
-            ),
-            'options'     => $varOptions,
+            'description' => $this->translate('Property of the Virtual Machine (as known by Icinga)'),
+            'options'     => $varOptions
         ]);
 
-        $submit = new SubmitElement('submit', [
-            'label' => $this->translate('Store')
-        ]);
+        $submit = new SubmitElement('submit', ['label' => $this->translate('Store')]);
         $this->addElement($submit);
 
         if ($id = $this->getId()) {
-            $delete = new SubmitElement('delete', [
-                'label' => $this->translate('Delete')
-            ]);
+            $delete = new SubmitElement('delete', ['label' => $this->translate('Delete')]);
             $deco = $submit->getWrapper();
             assert($deco instanceof DdDtDecorator);
             $deco->dd()->add($delete);
             $this->registerElement($delete);
             if ($delete->hasBeenPressed()) {
-                $this->db->delete(
-                    'monitoring_connection',
-                    $this->db->quoteInto('id = ?', $id)
-                );
+                $this->db->delete('monitoring_connection', $this->db->quoteInto('id = ?', $id));
                 Notification::success($this->translate('Monitoring Integration has been deleted'));
                 $this->hasBeenDeleted = true;
             }
@@ -200,61 +190,39 @@ protected function assemble()
 
     public function getId(): ?int
     {
-        if ($this->id === null) {
-            if ($id = QueryParams::fromRequest($this->getRequest())->get('id')) {
-                $this->id = (int) $id;
-            }
+        if ($this->id === null && $id = QueryParams::fromRequest($this->getRequest())->get('id')) {
+            $this->id = (int) $id;
         }
 
         return $this->id;
     }
 
-    public function onSuccess()
+    protected function onSuccess(): void
     {
         $values = $this->getValues();
         $db = $this->db;
         $id = $this->getId();
         $vCenterUuid = $this->getValue('vcenter');
-        if ($vCenterUuid === null) {
-            $values['vcenter_uuid'] = null;
-        } else {
-            $values['vcenter_uuid'] = Uuid::fromString($vCenterUuid)->getBytes();
-        }
+        $values['vcenter_uuid'] = $vCenterUuid !== null ? Uuid::fromString($vCenterUuid)->getBytes() : null;
         if ($id) {
-            $db->update(
-                'monitoring_connection',
-                $values,
-                $db->quoteInto('id = ?', $id)
-            );
+            $db->update('monitoring_connection', $values, $db->quoteInto('id = ?', $id));
             Notification::success($this->translate('Monitoring Integration has been modified'));
         } else {
-            $priority = (int) $db->fetchOne(
-                $db->select()->from('monitoring_connection', 'MAX(priority)')
-            ) + 1;
-            $db->insert('monitoring_connection', $values + [
-                    'priority'     => $priority,
-                ]);
+            $priority = (int) $db->fetchOne($db->select()->from('monitoring_connection', 'MAX(priority)')) + 1;
+            $db->insert('monitoring_connection', $values + ['priority' => $priority]);
             $this->id = (int) $db->lastInsertId();
             Notification::success($this->translate('Monitoring Integration has been created'));
         }
     }
 
-    protected function enumIcingadbCustomVars(DbConnection $db)
+    protected function enumIcingadbCustomVars(DbConnection $db): array
     {
         $dba = $db->getDbAdapter();
 
         $vars = $dba->fetchPairs(
-            $dba->select()->from(
-                ['cvs' => 'customvar'],
-                [
-                    'varname'   => 'cvs.name',
-                    'varcount' => 'COUNT(*)'
-                ]
-            )->join(
-                ['o' => 'host_customvar'],
-                'o.customvar_id = cvs.id',
-                []
-            )
+            $dba->select()
+                ->from(['cvs' => 'customvar'], ['varname' => 'cvs.name', 'varcount' => 'COUNT(*)'])
+                ->join(['o' => 'host_customvar'], 'o.customvar_id = cvs.id', [])
                 ->group('varname')
                 ->order('varname')
         );
@@ -267,24 +235,16 @@ protected function enumIcingadbCustomVars(DbConnection $db)
         return $result;
     }
 
-    protected function enumIdoCustomVars(DbConnection $db)
+    protected function enumIdoCustomVars(DbConnection $db): array
     {
         $dba = $db->getDbAdapter();
 
         $vars = $dba->fetchPairs(
-            $dba->select()->from(
-                ['cvs' => 'icinga_customvariablestatus'],
-                [
-                    'varname'   => 'cvs.varname',
-                    'varcount' => 'COUNT(*)'
-                ]
-            )->join(
-                ['o' => 'icinga_objects'],
-                'o.object_id = cvs.object_id AND o.is_active = 1',
-                []
-            )
-            ->group('varname')
-            ->order('varname')
+            $dba->select()
+                ->from(['cvs' => 'icinga_customvariablestatus'], ['varname' => 'cvs.varname', 'varcount' => 'COUNT(*)'])
+                ->join(['o' => 'icinga_objects'], 'o.object_id = cvs.object_id AND o.is_active = 1', [])
+                ->group('varname')
+                ->order('varname')
         );
 
         $result = [];
@@ -297,22 +257,20 @@ protected function enumIdoCustomVars(DbConnection $db)
 
     /**
      * UNUSED
+     *
      * @return array
      */
     protected function enumHostParents(): array
     {
         $db = $this->db;
-        $query = $db->select()->from(
-            ['p' => 'object'],
-            ['p.uuid', 'p.object_name']
-        )->join(
-            ['c' => 'object'],
-            'c.parent_uuid = p.uuid AND '
-            . $db->quoteInto('c.object_type = ?', 'HostSystem')
-            . ' AND '
-            . $db->quoteInto('p.object_type = ?', 'ClusterComputeResource'),
-            []
-        )->group('p.uuid')->order('p.object_name');
+        $query = $db->select()
+            ->from(['p' => 'object'], ['p.uuid', 'p.object_name'])
+            ->join(['c' => 'object'], sprintf(
+                'c.parent_uuid = p.uuid AND %s AND %s',
+                $db->quoteInto('c.object_type = ?', 'HostSystem'),
+                $db->quoteInto('p.object_type = ?', 'ClusterComputeResource')
+            ), [])
+            ->group('p.uuid')->order('p.object_name');
 
         return $this->makeNiceUuidKeys($db->fetchPairs($query));
     }
@@ -343,10 +301,9 @@ protected function enumIdoResourceNames(): array
     protected function enumVCenters(): array
     {
         return $this->makeNiceUuidKeys($this->db->fetchPairs(
-            $this->db->select()->from(['vc' => 'vcenter'], [
-                'uuid' => 'vc.instance_uuid',
-                'name' => 'vc.name',
-            ])->order('vc.name')
+            $this->db->select()
+                ->from(['vc' => 'vcenter'], ['uuid' => 'vc.instance_uuid', 'name' => 'vc.name'])
+                ->order('vc.name')
         ));
     }
 
diff --git a/library/Vspheredb/Web/Form/ObjectForm.php b/library/Vspheredb/Web/Form/ObjectForm.php
index e2d58025..b1295e89 100644
--- a/library/Vspheredb/Web/Form/ObjectForm.php
+++ b/library/Vspheredb/Web/Form/ObjectForm.php
@@ -2,35 +2,33 @@
 
 namespace Icinga\Module\Vspheredb\Web\Form;
 
+use gipfl\Web\Form;
+use gipfl\ZfDbStore\StorableInterface;
 use gipfl\ZfDbStore\Store;
 use Icinga\Authentication\Auth;
+use ipl\I18n\Translation;
 use Ramsey\Uuid\Uuid;
 use RuntimeException;
-use ipl\I18n\Translation;
-use gipfl\Web\Form;
-use gipfl\ZfDbStore\StorableInterface;
 
 abstract class ObjectForm extends Form
 {
     use Translation;
 
-    /** @var Store */
-    protected $store;
+    protected Store $store;
 
-    /** @var StorableInterface */
-    protected $object;
+    protected ?StorableInterface $object = null;
 
-    protected $class;
+    /** @var ?class-string */
+    protected ?string $class = null;
 
-    protected $wasNew = true;
+    protected bool $wasNew = true;
 
     public function __construct(Store $store)
     {
         $this->store = $store;
-        $this->setMethod('POST');
     }
 
-    public function setObject(StorableInterface $object)
+    public function setObject(StorableInterface $object): static
     {
         $this->object = $object;
         $this->populate($object->getProperties());
@@ -42,41 +40,38 @@ public function setObject(StorableInterface $object)
     /**
      * @return ?StorableInterface
      */
-    public function getObject()
+    public function getObject(): ?StorableInterface
     {
         return $this->object;
     }
 
-    public function wasNew()
+    public function wasNew(): bool
     {
         return $this->wasNew;
     }
 
-    public function isNew()
+    public function isNew(): bool
     {
-        return $this->object === null || $this->object->isNew();
+        return $this->object?->isNew() ?? true;
     }
 
-    protected function getObjectClass()
+    protected function getObjectClass(): string
     {
         if ($this->class === null) {
-            throw new RuntimeException(sprintf(
-                'ObjectForm %s defined no $class',
-                get_class($this)
-            ));
+            throw new RuntimeException(sprintf('ObjectForm %s defined no $class', get_class($this)));
         }
 
         return $this->class;
     }
 
-    protected static function now()
+    protected static function now(): float
     {
         $time = explode(' ', microtime());
 
         return round(1000 * ((int)$time[1] + (float)$time[0]));
     }
 
-    public function onSuccess()
+    protected function onSuccess(): void
     {
         if ($this->object) {
             $object = $this->object;
@@ -94,7 +89,7 @@ public function onSuccess()
         $this->store->store($object);
     }
 
-    protected function createObject()
+    protected function createObject(): mixed
     {
         /** @var StorableInterface $class Not really an object, it's a class name */
         $class = $this->getObjectClass();
diff --git a/library/Vspheredb/Web/Form/PerfdataConsumerForm.php b/library/Vspheredb/Web/Form/PerfdataConsumerForm.php
index 06c18679..4ff9c141 100644
--- a/library/Vspheredb/Web/Form/PerfdataConsumerForm.php
+++ b/library/Vspheredb/Web/Form/PerfdataConsumerForm.php
@@ -2,13 +2,11 @@
 
 namespace Icinga\Module\Vspheredb\Web\Form;
 
-use ipl\I18n\Translation;
-use gipfl\Web\Form\Decorator\DdDtDecorator;
 use gipfl\ZfDbStore\Store;
 use Icinga\Module\Vspheredb\Daemon\RemoteClient;
 use Icinga\Module\Vspheredb\Hook\PerfDataConsumerHook;
 use Icinga\Module\Vspheredb\Storable\PerfdataConsumer;
-use ipl\Html\FormElement\SubmitElement;
+use ipl\I18n\Translation;
 use React\EventLoop\LoopInterface;
 
 class PerfdataConsumerForm extends ObjectForm
@@ -18,13 +16,11 @@ class PerfdataConsumerForm extends ObjectForm
 
     public const ON_DELETE = 'delete';
 
-    protected $class = PerfdataConsumer::class;
+    protected ?string $class = PerfdataConsumer::class;
 
-    /** @var RemoteClient */
-    protected $client;
+    protected RemoteClient $client;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
     public function __construct(LoopInterface $loop, RemoteClient $client, Store $store)
     {
@@ -33,17 +29,17 @@ public function __construct(LoopInterface $loop, RemoteClient $client, Store $st
         parent::__construct($store);
     }
 
-    public function assemble()
+    protected function assemble(): void
     {
         $this->addElement('text', 'name', [
             'label'       => $this->translate('Name'),
             'required'    => true,
-            'description' => $this->translate('Arbitrary unique name for this Performance Data Consumer'),
+            'description' => $this->translate('Arbitrary unique name for this Performance Data Consumer')
         ]);
         $this->addElement('boolean', 'enabled', [
             'label' => $this->translate('Enabled'),
             'value' => 'y',
-            'required' => true,
+            'required' => true
         ]);
         if ($this->object instanceof PerfdataConsumer && !$this->hasBeenSent()) {
             $this->populate((array) $this->object->settings());
@@ -56,7 +52,7 @@ public function assemble()
         $this->addButtons(isset($implementation), 'implementation');
     }
 
-    public function isValidEvent($event)
+    public function isValidEvent($event): bool
     {
         if ($event === self::ON_DELETE) {
             return true;
@@ -65,7 +61,7 @@ public function isValidEvent($event)
         return parent::isValidEvent($event);
     }
 
-    protected function selectImplementation()
+    protected function selectImplementation(): ?string
     {
         if (! $this->isNew()) {
             return $this->object->get('implementation');
@@ -74,13 +70,13 @@ protected function selectImplementation()
             'label'    => $this->translate('Implementation'),
             'options'  => ['' => $this->translate('- please choose -')] + PerfDataConsumerHook::enum(),
             'required' => true,
-            'class'    => 'autosubmit',
+            'class'    => 'autosubmit'
         ]);
 
         return $this->getValue('implementation');
     }
 
-    protected function addImplementation($implementation)
+    protected function addImplementation(string $implementation): void
     {
         /** @var PerfDataConsumerHook $instance */
         $class = PerfDataConsumerHook::getClass($implementation);
@@ -89,6 +85,7 @@ protected function addImplementation($implementation)
                 $this->translate('There is no such PerfdataConsumer: %s'),
                 $implementation
             ));
+
             return;
         }
         $instance = new $class();
diff --git a/library/Vspheredb/Web/Form/RestartDaemonForm.php b/library/Vspheredb/Web/Form/RestartDaemonForm.php
index 6215bb0c..1da1c496 100644
--- a/library/Vspheredb/Web/Form/RestartDaemonForm.php
+++ b/library/Vspheredb/Web/Form/RestartDaemonForm.php
@@ -14,11 +14,9 @@ class RestartDaemonForm extends InlineForm
 {
     use Translation;
 
-    /** @var RemoteClient */
-    protected $client;
+    protected RemoteClient $client;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
     public function __construct(RemoteClient $client, LoopInterface $loop)
     {
@@ -26,18 +24,18 @@ public function __construct(RemoteClient $client, LoopInterface $loop)
         $this->loop = $loop;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         (new NextConfirmCancel(
             NextConfirmCancel::buttonNext($this->translate('Restart'), [
-                'title' => $this->translate('Click to restart the vSphereDB background daemon'),
+                'title' => $this->translate('Click to restart the vSphereDB background daemon')
             ]),
             NextConfirmCancel::buttonConfirm($this->translate('Yes, please restart')),
             NextConfirmCancel::buttonCancel($this->translate('Cancel'))
         ))->addToForm($this);
     }
 
-    protected function onSuccess()
+    protected function onSuccess(): void
     {
         await($this->client->request('process.restart'));
     }
diff --git a/library/Vspheredb/Web/Form/ServerActionForm.php b/library/Vspheredb/Web/Form/ServerActionForm.php
new file mode 100644
index 00000000..4710a910
--- /dev/null
+++ b/library/Vspheredb/Web/Form/ServerActionForm.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace Icinga\Module\Vspheredb\Web\Form;
+
+use gipfl\Web\Form\Feature\NextConfirmCancel;
+use gipfl\Web\InlineForm;
+use Icinga\Exception\ProgrammingError;
+use ipl\I18n\Translation;
+use Zend_Db_Adapter_Abstract;
+
+class ServerActionForm extends InlineForm
+{
+    use Translation;
+
+    /** @var ?string Set to either 'enable' or 'disable' */
+    protected ?string $serverAction = null;
+
+    protected int $serverId;
+
+    protected Zend_Db_Adapter_Abstract $db;
+
+    public function __construct(int $serverId, Zend_Db_Adapter_Abstract $db)
+    {
+        $this->serverId = $serverId;
+        $this->db = $db;
+    }
+
+    public function getUniqueFormName(): string
+    {
+        return parent::getUniqueFormName() . '-' . $this->serverId;
+    }
+
+    protected function assemble(): void
+    {
+        (new NextConfirmCancel(
+            NextConfirmCancel::buttonNext($this->translate(ucfirst($this->serverAction))),
+            NextConfirmCancel::buttonConfirm($this->translate('Really ' . $this->serverAction)),
+            NextConfirmCancel::buttonCancel($this->translate('Cancel'))
+        ))->addToForm($this);
+    }
+
+    protected function onSuccess(): void
+    {
+        $enabled = match ($this->serverAction) {
+            'enable'  => 'y',
+            'disable' => 'n',
+            default   => throw new ProgrammingError('Invalid server action provided: %s', $this->serverAction)
+        };
+        $this->db->update('vcenter_server', ['enabled' => $enabled], $this->db->quoteInto('id = ?', $this->serverId));
+    }
+}
diff --git a/library/Vspheredb/Web/Form/VCenterForm.php b/library/Vspheredb/Web/Form/VCenterForm.php
index 4a691a34..226399b8 100644
--- a/library/Vspheredb/Web/Form/VCenterForm.php
+++ b/library/Vspheredb/Web/Form/VCenterForm.php
@@ -11,8 +11,7 @@ class VCenterForm extends Form
 {
     use Translation;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     public function __construct(VCenter $vCenter)
     {
@@ -20,7 +19,7 @@ public function __construct(VCenter $vCenter)
         $this->populate($vCenter->getProperties());
     }
 
-    public function assemble()
+    protected function assemble(): void
     {
         $this->add(Html::tag('h3', $this->translate('Rename this vCenter')));
         $this->addElement('text', 'name', [
@@ -28,14 +27,14 @@ public function assemble()
             'description' => $this->translate(
                 'You might want to change the display name of your vCenter.'
                 . ' This defaults to the first related Server host name.'
-            ),
+            )
         ]);
         $this->addElement('submit', 'submit', [
             'label' => $this->translate('Rename')
         ]);
     }
 
-    public function onSuccess()
+    protected function onSuccess(): void
     {
         $this->vCenter->setProperties($this->getValues())->store();
     }
diff --git a/library/Vspheredb/Web/Form/VCenterServerForm.php b/library/Vspheredb/Web/Form/VCenterServerForm.php
index e3f88352..76f58e98 100644
--- a/library/Vspheredb/Web/Form/VCenterServerForm.php
+++ b/library/Vspheredb/Web/Form/VCenterServerForm.php
@@ -4,7 +4,6 @@
 
 use gipfl\Web\Form;
 use Icinga\Module\Vspheredb\Db;
-use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
 use Icinga\Module\Vspheredb\DbObject\VCenterServer;
 use ipl\Html\FormElement\SubmitElement;
 use ipl\I18n\Translation;
@@ -15,26 +14,21 @@ class VCenterServerForm extends Form
 
     public const UNCHANGED_PASSWORD = '__UNCHANGED__';
 
-    protected $objectClassName = VCenterServer::class;
+    protected ?VCenterServer $object = null;
 
-    /** @var VCenterServer */
-    protected $object;
+    protected Db $db;
 
-    protected $db;
-
-    protected $deleted = false;
+    protected bool $deleted = false;
 
     public function __construct(Db $db)
     {
         $this->db = $db;
     }
 
-    public function assemble()
+    protected function assemble(): void
     {
         if (! class_exists('SoapClient')) {
-            $this->addMessage($this->translate(
-                'The PHP SOAP extension (php-soap) is not installed/enabled'
-            ));
+            $this->addMessage($this->translate('The PHP SOAP extension (php-soap) is not installed/enabled'));
 
             return;
         }
@@ -49,31 +43,27 @@ public function assemble()
                 . ' HTTP(s) ports'
             ),
             'class' => 'autofocus',
-            'required' => true,
+            'required' => true
         ]);
 
         $this->addElement('select', 'scheme', [
             'label' => $this->translate('Protocol'),
-            'description' => $this->translate(
-                'Whether to use encryption when talking to your vCenter'
-            ),
+            'description' => $this->translate('Whether to use encryption when talking to your vCenter'),
             'multiOptions' => [
                 'https' => $this->translate('HTTPS (strongly recommended)'),
-                'http'  => $this->translate('HTTP (this is plaintext!)'),
+                'http'  => $this->translate('HTTP (this is plaintext!)')
             ],
             'class' => 'autosubmit',
             'value' => 'https',
-            'required' => true,
+            'required' => true
         ]);
 
         $ssl = $this->getValue('scheme', 'https') === 'https';
         $this->addElement('boolean', 'enabled', [
             'label'       => $this->translate('Enabled'),
-            'description' => $this->translate(
-                'Whether the background daemon should actively poll this node.'
-            ),
+            'description' => $this->translate('Whether the background daemon should actively poll this node.'),
             'required'    => true,
-            'value'       => 'y',
+            'value'       => 'y'
         ]);
 
         if ($ssl) {
@@ -84,38 +74,31 @@ public function assemble()
                     . ' been signed by a trusted CA. This is strongly recommended.'
                 ),
                 'required'    => true,
-                'value'       => 'y',
+                'value'       => 'y'
             ]);
             $this->addElement('boolean', 'ssl_verify_host', [
                 'label'       => $this->translate('Verify Host'),
                 'description' => $this->translate(
-                    'Whether we should check that the certificate matches the'
-                    . 'configured host'
+                    'Whether we should check that the certificate matches the configured host'
                 ),
                 'value'       => 'y',
-                'required'    => true,
+                'required'    => true
             ]);
         }
 
         $this->addElement('text', 'username', [
             'label'       => $this->translate('Username'),
-            'description' => $this->translate(
-                'Will be used for SOAP authentication against your vCenter'
-            ),
-            'required'    => true,
+            'description' => $this->translate('Will be used for SOAP authentication against your vCenter'),
+            'required'    => true
         ]);
 
-        if ($this->isNew()) {
-            $this->addElement('password', 'password', [
-                'label' => $this->translate('Password'),
-                'required' => true,
-            ]);
-        } else {
-            $this->addElement('password', 'password', [
-                'label' => $this->translate('Password'),
-                'placeholder' => $this->translate('(keep as stored)'),
-            ]);
-        }
+        $this->addElement(
+            'password',
+            'password',
+            ['label' => $this->translate('Password')] + ($this->isNew()
+                ? ['required' => true]
+                : ['placeholder' => $this->translate('(keep as stored)')])
+        );
 
         $this->addElement('select', 'proxy_type', [
             'label' => $this->translate('Proxy'),
@@ -126,7 +109,7 @@ public function assemble()
             'multiOptions' => [
                 '' => $this->translate('- please choose -'),
                 'HTTP' => $this->translate('HTTP proxy'),
-                'SOCKS5' => $this->translate('SOCKS5 proxy'),
+                'SOCKS5' => $this->translate('SOCKS5 proxy')
             ],
             'class' => 'autosubmit'
         ]);
@@ -136,21 +119,18 @@ public function assemble()
         if ($proxyType) {
             $this->addElement('text', 'proxy_address', [
                 'label' => $this->translate('Proxy Address'),
-                'description' => $this->translate(
-                    'Hostname, IP or <host>:<port>'
-                ),
-                'required' => true,
+                'description' => $this->translate('Hostname, IP or <host>:<port>'),
+                'required' => true
             ]);
             if ($proxyType === 'HTTP') {
                 $this->addElement('text', 'proxy_user', [
                     'label' => $this->translate('Proxy Username'),
                     'description' => $this->translate(
-                        'In case your proxy requires authentication, please'
-                        . ' configure this here'
-                    ),
+                        'In case your proxy requires authentication, please configure this here'
+                    )
                 ]);
 
-                $passRequired = $this->getValue('proxy_user') !== null && \strlen($this->getValue('proxy_user')) > 0;
+                $passRequired = $this->getValue('proxy_user') !== null && strlen($this->getValue('proxy_user')) > 0;
 
                 $this->addElement('password', 'proxy_pass', [
                     'label' => $this->translate('Proxy Password'),
@@ -164,9 +144,7 @@ public function assemble()
             'label' => $this->isNew() ? $this->translate('Create') : $this->translate('Store')
         ]);
         if (! $this->isNew()) {
-            $buttons[] = $deleteButton = new SubmitElement('btn_delete', [
-                'label' => $this->translate('Delete')
-            ]);
+            $buttons[] = $deleteButton = new SubmitElement('btn_delete', ['label' => $this->translate('Delete')]);
         } else {
             $deleteButton = null;
         }
@@ -180,12 +158,12 @@ public function assemble()
         }
     }
 
-    public function isNew()
+    public function isNew(): bool
     {
         return $this->object === null || ! $this->object->hasBeenLoadedFromDb();
     }
 
-    public function getValues()
+    public function getValues(): array
     {
         $values = parent::getValues();
         if (! $this->isNew()) {
@@ -200,14 +178,14 @@ public function getValues()
         return $values;
     }
 
-    public function setObject(VCenterServer $object)
+    public function setObject(VCenterServer $object): static
     {
         $this->object = $object;
         $properties = $object->getProperties();
-        if ($properties['password'] !== null && \strlen($properties['password'])) {
+        if ($properties['password'] !== null && strlen($properties['password'])) {
             $properties['password'] = self::UNCHANGED_PASSWORD;
         }
-        if ($properties['proxy_pass'] !== null && \strlen($properties['proxy_pass'])) {
+        if ($properties['proxy_pass'] !== null && strlen($properties['proxy_pass'])) {
             $properties['proxy_pass'] = self::UNCHANGED_PASSWORD;
         }
         $this->populate($properties);
@@ -216,25 +194,19 @@ public function setObject(VCenterServer $object)
     }
 
     /**
-     * @return BaseDbObject
+     * @return VCenterServer
      */
-    public function getObject()
+    public function getObject(): VCenterServer
     {
-        if ($this->object === null) {
-            /** @var BaseDbObject $class */
-            $class = $this->objectClassName;
-            $this->object = $class::create([], $this->db);
-        }
-
-        return $this->object;
+        return $this->object ??= VCenterServer::create([], $this->db);
     }
 
-    public function hasBeenDeleted()
+    public function hasBeenDeleted(): bool
     {
         return $this->deleted;
     }
 
-    public function onSuccess()
+    protected function onSuccess(): void
     {
         $this->getObject()->setProperties($this->getValues());
     }
diff --git a/library/Vspheredb/Web/Form/VCenterShipMetricsForm.php b/library/Vspheredb/Web/Form/VCenterShipMetricsForm.php
index a4a7f8c7..78111fbf 100644
--- a/library/Vspheredb/Web/Form/VCenterShipMetricsForm.php
+++ b/library/Vspheredb/Web/Form/VCenterShipMetricsForm.php
@@ -21,19 +21,16 @@ class VCenterShipMetricsForm extends ObjectForm
 
     public const ON_DELETE = 'delete';
 
-    protected $class = PerfdataSubscription::class;
+    protected ?string $class = PerfdataSubscription::class;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
-    /** @var PerfdataConsumer[] */
-    protected $consumers;
+    /** @var ?PerfdataConsumer[] */
+    protected ?array $consumers = null;
 
-    /** @var RemoteClient */
-    protected $remoteClient;
+    protected RemoteClient $remoteClient;
 
-    /** @var LoopInterface */
-    protected $loop;
+    protected LoopInterface $loop;
 
     public function __construct(ZfDbStore $store, VCenter $vCenter, RemoteClient $client, LoopInterface $loop)
     {
@@ -44,10 +41,13 @@ public function __construct(ZfDbStore $store, VCenter $vCenter, RemoteClient $cl
         $this->populate($vCenter->getProperties());
     }
 
-    protected function fetchConsumers()
+    /**
+     * @return PerfdataConsumer[]
+     */
+    protected function fetchConsumers(): array
     {
         $db = $this->vCenter->getConnection()->getDbAdapter();
-        /** @var PerfdataConsumer $consumers */
+        /** @var PerfdataConsumer[] $consumers */
         $consumers = [];
         foreach ($db->fetchAll($db->select()->from('perfdata_consumer')) as $row) {
             $consumers[Uuid::fromBytes($row->uuid)->toString()] = PerfdataConsumer::create((array) $row);
@@ -56,17 +56,12 @@ protected function fetchConsumers()
         return $consumers;
     }
 
-    protected function enumConsumers($consumers)
+    protected function enumConsumers($consumers): array
     {
-        $result = [];
-        foreach ($consumers as $uuid => $consumer) {
-            $result[$uuid] = $consumer->get('name');
-        }
-
-        return $result;
+        return array_map(fn ($consumer) => $consumer->get('name'), $consumers);
     }
 
-    public function assemble()
+    protected function assemble(): void
     {
         $this->add(Html::tag('h3', $this->translate('Ship Performance Data')));
         if ($this->object instanceof PerfdataSubscription && !$this->hasBeenSent()) {
@@ -80,16 +75,12 @@ public function assemble()
     }
 
     /**
-     * @return PerfdataConsumer|null
+     * @return ?PerfdataConsumer
      */
-    protected function selectConsumer()
+    protected function selectConsumer(): ?PerfdataConsumer
     {
         $consumers = $this->fetchConsumers();
-        if ($this->object) {
-            $consumer = Uuid::fromBytes($this->object->get('consumer_uuid'))->toString();
-        } else {
-            $consumer = null;
-        }
+        $consumer = $this->object ? Uuid::fromBytes($this->object->get('consumer_uuid'))->toString() : null;
         $this->addElement('select', 'consumer', [
             'label' => $this->translate('Consumer'),
             'options' => ['' => $this->translate('- please choose -')] + $this->enumConsumers($consumers),
@@ -99,11 +90,9 @@ protected function selectConsumer()
             ),
             'required' => true,
             'value' => $consumer,
-            'class' => 'autosubmit',
-        ]);
-        $this->addHidden('enabled', [
-            'value' => 'y'
+            'class' => 'autosubmit'
         ]);
+        $this->addHidden('enabled', ['value' => 'y']);
 
         $value = $this->getValue('consumer') ?? '';
         if (isset($consumers[$value])) {
@@ -113,7 +102,7 @@ protected function selectConsumer()
         return null;
     }
 
-    protected function addConsumerConfig($consumer)
+    protected function addConsumerConfig($consumer): void
     {
         $instance = PerfDataConsumerHook::createConsumerInstance($consumer, $this->loop);
         if ($form = $instance->getSubscriptionForm($this->remoteClient)) {
@@ -121,7 +110,7 @@ protected function addConsumerConfig($consumer)
         }
     }
 
-    public function isValidEvent($event)
+    public function isValidEvent($event): bool
     {
         if ($event === self::ON_DELETE) {
             return true;
@@ -130,7 +119,7 @@ public function isValidEvent($event)
         return parent::isValidEvent($event);
     }
 
-    public function createObject()
+    public function createObject(): mixed
     {
         $object = parent::createObject();
         $object->set('vcenter_uuid', $this->vCenter->get('instance_uuid'));
diff --git a/library/Vspheredb/Web/OverviewTree.php b/library/Vspheredb/Web/OverviewTree.php
index 628b3509..4c751e25 100644
--- a/library/Vspheredb/Web/OverviewTree.php
+++ b/library/Vspheredb/Web/OverviewTree.php
@@ -8,35 +8,34 @@
 use Icinga\Module\Vspheredb\Util;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\I18n\Translation;
 
 class OverviewTree extends BaseHtmlElement
 {
     use Translation;
 
-    /** @var Db */
-    protected $db;
+    protected Db $db;
 
-    /** @var RestrictionHelper */
-    protected $restrictionHelper;
+    protected RestrictionHelper $restrictionHelper;
 
     protected $tag = 'ul';
 
     protected $defaultAttributes = [
         'class'            => 'tree',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    protected $typeFilter;
+    protected ?string $typeFilter;
 
-    public function __construct(Db $db, RestrictionHelper $restrictionHelper, $typeFilter = null)
+    public function __construct(Db $db, RestrictionHelper $restrictionHelper, ?string $typeFilter = null)
     {
         $this->db = $db;
         $this->typeFilter = $typeFilter;
         $this->restrictionHelper = $restrictionHelper;
     }
 
-    public function renderContent()
+    public function renderContent(): string
     {
         $this->add(
             $this->dumpTree(
@@ -51,18 +50,11 @@ public function renderContent()
         return parent::renderContent();
     }
 
-    protected function getTree()
+    protected function getTree(): array
     {
         $tree = [];
         $all = [];
         foreach ($this->fetchTree() as $item) {
-            if (
-                $this->typeFilter
-                && (string) $item->parent_object_type === 'Datacenter'
-                && $item->object_name !== $this->typeFilter
-            ) {
-                // continue; // see #260
-            }
             $item->children = [];
 
             /** @var string $uuid */
@@ -81,37 +73,30 @@ protected function getTree()
         return $tree;
     }
 
-    protected function fetchTree()
+    protected function fetchTree(): ?array
     {
         $db = $this->db->getDbAdapter();
-        $hostCnt = $db->select()->from('object', [
-            'cnt'         => 'COUNT(*)',
-            'parent_uuid' => 'parent_uuid'
-        ])->where('object_type = ?', 'HostSystem')->group('parent_uuid');
-        $vmCnt = $db->select()->from('object', [
-            'cnt'         => 'COUNT(*)',
-            'parent_uuid' => 'parent_uuid'
-        ])->where('object_type = ?', 'VirtualMachine')->group('parent_uuid');
-        $dsCnt = $db->select()->from('object', [
-            'cnt'         => 'COUNT(*)',
-            'parent_uuid' => 'parent_uuid'
-        ])->where('object_type = ?', 'Datastore')->group('parent_uuid');
-        $networkCnt = $db->select()->from('object', [
-            'cnt'         => 'COUNT(*)',
-            'parent_uuid' => 'parent_uuid'
-        ])->where('object_type = ?', 'DistributedVirtualSwitch')->group('parent_uuid');
+        $hostCnt = $db->select()
+            ->from('object', ['cnt' => 'COUNT(*)', 'parent_uuid' => 'parent_uuid'])
+            ->where('object_type = ?', 'HostSystem')
+            ->group('parent_uuid');
+        $vmCnt = $db->select()
+            ->from('object', ['cnt' => 'COUNT(*)', 'parent_uuid' => 'parent_uuid'])
+            ->where('object_type = ?', 'VirtualMachine')
+            ->group('parent_uuid');
+        $dsCnt = $db->select()
+            ->from('object', ['cnt' => 'COUNT(*)', 'parent_uuid' => 'parent_uuid'])
+            ->where('object_type = ?', 'Datastore')
+            ->group('parent_uuid');
+        $networkCnt = $db->select()
+            ->from('object', ['cnt' => 'COUNT(*)', 'parent_uuid' => 'parent_uuid'])
+            ->where('object_type = ?', 'DistributedVirtualSwitch')
+            ->group('parent_uuid');
 
         $main = $db->select()
-            ->from(['o' => 'object'], [
-                'o.*',
-                'parent_object_type' => 'po.object_type',
-            ])
+            ->from(['o' => 'object'], ['o.*', 'parent_object_type' => 'po.object_type'])
             ->joinLeft(['po' => 'object'], 'po.uuid = o.parent_uuid', [])
-            ->where(' o.object_type NOT IN (?)', [
-                'VirtualMachine',
-                'HostSystem',
-                'Datastore'
-            ]);
+            ->where(' o.object_type NOT IN (?)', ['VirtualMachine', 'HostSystem', 'Datastore']);
         $this->restrictionHelper->filterQuery($hostCnt);
         $this->restrictionHelper->filterQuery($vmCnt);
         $this->restrictionHelper->filterQuery($dsCnt);
@@ -123,7 +108,7 @@ protected function fetchTree()
                 'cnt_host'    => 'hc.cnt',
                 'cnt_vm'      => 'vc.cnt',
                 'cnt_ds'      => 'dc.cnt',
-                'cnt_network' => 'nc.cnt',
+                'cnt_network' => 'nc.cnt'
             ])
             ->joinLeft(['vc' => $vmCnt], 'vc.parent_uuid = f.uuid', [])
             ->joinLeft(['hc' => $hostCnt], 'hc.parent_uuid = f.uuid', [])
@@ -135,54 +120,41 @@ protected function fetchTree()
         return $this->db->getDbAdapter()->fetchAll($query);
     }
 
-    protected function dumpTree($tree, $level = 0)
+    protected function dumpTree(object $tree, int $level = 0): HtmlElement
     {
         $hasChildren = ! empty($tree->children);
         $type = $tree->object_type;
         $li = Html::tag('li');
-        if (! $hasChildren) {
-            $li->getAttributes()->add('class', 'collapsed');
-        }
 
         if ($hasChildren) {
             $li->add(Html::tag('span', ['class' => 'handle']));
+        } else {
+            $li->getAttributes()->add('class', 'collapsed');
         }
 
         if ($level === 0) {
-            $li->add(Html::tag('a', [
-                'name'  => $tree->object_name,
-                'class' => 'icon-globe'
-            ], $tree->object_name));
+            $li->add(Html::tag('a', ['name' => $tree->object_name, 'class' => 'icon-globe'], $tree->object_name));
         } else {
             $count = $tree->cnt_vm + $tree->cnt_host + $tree->cnt_ds;
-            if ($count) {
-                $label = sprintf('%s (%d)', $tree->object_name, $count);
-                // $label = sprintf('%s (%d VMs, %d Hosts)', $tree->object_name, $tree->cnt_vm, $tree->cnt_host);
-            } else {
-                $label = $tree->object_name;
-            }
-            $attributes = [
-                'class' => [$this->getClassByType($type), $tree->overall_status]
-            ];
+            $label = $count ? sprintf('%s (%d)', $tree->object_name, $count) : $tree->object_name;
+            $attributes = ['class' => [$this->getClassByType($type), $tree->overall_status]];
 
-            if ($count) {
-                $li->add(Link::create(
+            $link = $count
+                ? Link::create(
                     $label,
                     $tree->cnt_host > 0
                         ? 'vspheredb/hosts'
                         : ($tree->cnt_ds > 0 ? 'vspheredb/datastores' : 'vspheredb/vms'),
                     Util::uuidParams($tree->uuid),
                     $attributes
-                ));
-            } else {
-                $li->add(Html::tag('a', $attributes, $label));
-            }
+                )
+                : Html::tag('a', $attributes, $label);
+
+            $li->add($link);
         }
 
         if ($hasChildren) {
-            $li->add(
-                $ul = Html::tag('ul')
-            );
+            $li->add($ul = Html::tag('ul'));
             foreach ($tree->children as $child) {
                 $ul->add($this->dumpTree($child, $level + 1));
             }
@@ -198,27 +170,22 @@ protected function dumpTree($tree, $level = 0)
      */
     protected function getClassByType(string $type): string
     {
-        $typeClasses = [
-            'ComputeResource'        => 'cubes',
-            'ClusterComputeResource' => 'cubes',
-            'Datacenter'             => 'home',
-            'DistributedVirtualPortgroup' => 'plug',
-            'DistributedVirtualSwitch' => 'sitemap',
+        return 'icon-' . match ($type) {
+            'ComputeResource',
+            'ClusterComputeResource'         => 'cubes',
+            'Datacenter'                     => 'home',
+            'DistributedVirtualPortgroup'    => 'plug',
+            'DistributedVirtualSwitch',
             'VmwareDistributedVirtualSwitch' => 'sitemap',
-            'Datastore'              => 'database',
-            // 'DatastoreHostMount',
-            'Folder'                 => 'folder-empty',
-            'Network'                => 'arrows-cw',
-            'ResourcePool'           => 'chart-pie',
-            'StoragePod'             => 'cloud',
-            'HostSystem'             => 'host',
-            'VirtualApp'             => 'th-thumb-empty',
-            'VirtualMachine'         => 'service',
-        ];
-        if (isset($typeClasses[$type])) {
-            return 'icon-' . $typeClasses[$type];
-        } else {
-            return 'icon-attention-alt';
-        }
+            'Datastore'                      => 'database',
+            'Folder'                         => 'folder-empty',
+            'Network'                        => 'arrows-cw',
+            'ResourcePool'                   => 'chart-pie',
+            'StoragePod'                     => 'cloud',
+            'HostSystem'                     => 'host',
+            'VirtualApp'                     => 'th-thumb-empty',
+            'VirtualMachine'                 => 'service',
+            default                          => 'attention-alt'
+        };
     }
 }
diff --git a/library/Vspheredb/Web/QueryParams.php b/library/Vspheredb/Web/QueryParams.php
index a77aee6f..54ca628b 100644
--- a/library/Vspheredb/Web/QueryParams.php
+++ b/library/Vspheredb/Web/QueryParams.php
@@ -7,9 +7,9 @@
 
 class QueryParams
 {
-    protected $params;
+    protected array $params;
 
-    protected function __construct($params)
+    protected function __construct(array $params)
     {
         $this->params = $params;
     }
@@ -19,24 +19,24 @@ public static function fromRequest(ServerRequestInterface $request): QueryParams
         return new static($request->getQueryParams());
     }
 
-    public function has($key): bool
+    public function has(string $key): bool
     {
-        return \array_key_exists($key, $this->params);
+        return array_key_exists($key, $this->params);
     }
 
     /**
      * @param string $key
-     * @param $default
+     * @param mixed $default
      *
-     * @return mixed|null
+     * @return ?mixed
      */
-    public function get(string $key, $default = null): mixed
+    public function get(string $key, mixed $default = null): mixed
     {
         if ($this->has($key)) {
             return $this->params[$key];
-        } else {
-            return $default;
         }
+
+        return $default;
     }
 
     /**
@@ -48,8 +48,8 @@ public function getRequired(string $key): mixed
     {
         if ($this->has($key)) {
             return $this->params[$key];
-        } else {
-            throw new InvalidArgumentException("Parameter '$key' is required");
         }
+
+        throw new InvalidArgumentException("Parameter '$key' is required");
     }
 }
diff --git a/library/Vspheredb/Web/Table/AlarmHistoryTable.php b/library/Vspheredb/Web/Table/AlarmHistoryTable.php
index 2566a705..b02e6e8b 100644
--- a/library/Vspheredb/Web/Table/AlarmHistoryTable.php
+++ b/library/Vspheredb/Web/Table/AlarmHistoryTable.php
@@ -3,59 +3,55 @@
 namespace Icinga\Module\Vspheredb\Web\Table;
 
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Date\DateFormatter;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class AlarmHistoryTable extends ZfQueryBasedTable
 {
     use UuidLinkHelper;
 
-    protected $entityUuid;
+    protected ?string $entityUuid = null;
 
     protected $defaultAttributes = [
         'class' => 'common-table',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    public function filterEntityUuid($uuid)
+    public function filterEntityUuid($uuid): static
     {
         $this->entityUuid = $uuid;
 
         return $this;
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $this->renderDayIfNew($row->ts_event_ms / 1000);
-        $content = [
-            DateFormatter::formatTime($row->ts_event_ms / 1000),
-        ];
+        $content = [DateFormatter::formatTime($row->ts_event_ms / 1000)];
 
         if ($this->entityUuid === null) {
             $this->linkToUuid($row->entity_uuid);
         }
         $content[] = $row->full_message;
 
-        $tr = $this::row($content);
-
-        return $tr;
+        return $this::row($content);
     }
-    protected function timeSince($ms)
+
+    protected function timeSince(int $ms): ?string
     {
         return DateFormatter::timeAgo($ms);
     }
 
-    protected function prepareQuery()
+    protected function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from([
-            'ah' => 'alarm_history'
-        ])->order('ts_event_ms DESC');
+        $query = $this->db()->select()
+            ->from(['ah' => 'alarm_history'])
+            ->order('ts_event_ms DESC');
 
         if ($this->entityUuid === null) {
-            $query->join(
-                ['o' => 'object'],
-                'o.uuid = ah.entity_uuid',
-                []
-            );
+            $query->join(['o' => 'object'], 'o.uuid = ah.entity_uuid', []);
         } else {
             $query->where('ah.entity_uuid = ?', $this->entityUuid);
         }
diff --git a/library/Vspheredb/Web/Table/ArrayTable.php b/library/Vspheredb/Web/Table/ArrayTable.php
index f5a620c2..7ae93a74 100644
--- a/library/Vspheredb/Web/Table/ArrayTable.php
+++ b/library/Vspheredb/Web/Table/ArrayTable.php
@@ -5,10 +5,13 @@
 use gipfl\IcingaWeb2\Data\SimpleQueryPaginationAdapter;
 use gipfl\IcingaWeb2\Table\QueryBasedTable;
 use Icinga\Data\DataArray\ArrayDatasource;
+use Icinga\Data\SimpleQuery;
+use ipl\Html\HtmlElement;
+use stdClass;
 
 class ArrayTable extends QueryBasedTable
 {
-    /** @var \stdClass */
+    /** @var stdClass */
     protected $rows;
 
     public function __construct($rows)
@@ -17,27 +20,27 @@ public function __construct($rows)
         $this->getAttributes()->set('data-base-target', '_self');
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         return $this::row((array) $row);
     }
 
-    protected function getPaginationAdapter()
+    protected function getPaginationAdapter(): SimpleQueryPaginationAdapter
     {
         return new SimpleQueryPaginationAdapter($this->getQuery());
     }
 
-    public function getQuery()
+    public function getQuery(): SimpleQuery
     {
         return $this->prepareQuery();
     }
 
-    protected function fetchQueryRows()
+    protected function fetchQueryRows(): array
     {
         return $this->getQuery()->fetchAll();
     }
 
-    protected function prepareQuery()
+    protected function prepareQuery(): SimpleQuery
     {
         return (new ArrayDatasource(array_values((array) $this->rows)))->select();
     }
diff --git a/library/Vspheredb/Web/Table/BaseTable.php b/library/Vspheredb/Web/Table/BaseTable.php
index 09a2f073..8bec5031 100644
--- a/library/Vspheredb/Web/Table/BaseTable.php
+++ b/library/Vspheredb/Web/Table/BaseTable.php
@@ -8,34 +8,31 @@
 use gipfl\IcingaWeb2\Url;
 use Icinga\Module\Vspheredb\Web\Widget\ToggleTableColumns;
 use InvalidArgumentException;
+use ipl\Html\Attributes;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
 use ipl\Html\HtmlElement;
+use RuntimeException;
 
 abstract class BaseTable extends ZfQueryBasedTable
 {
     /** @var TableColumn[] */
-    private $availableColumns = [];
+    private array $availableColumns = [];
 
-    /** @var TableColumn[] */
-    private $chosenColumns;
+    /** @var ?TableColumn[] */
+    private ?array $chosenColumns = null;
 
-    /** @var bool */
-    private $isInitialized = false;
+    private ?bool $isInitialized = false;
 
-    /** @var Url */
-    private $baseUrl;
+    private ?Url $baseUrl = null;
 
-    /** @var string */
-    private $sortParam;
+    private ?string $sortParam = null;
 
-    /** @var array */
-    private $sortColums = [];
+    private array $sortColums = [];
 
-    /** @var BaseHtmlElement|null */
-    private $columnToggle;
+    private ?BaseHtmlElement $columnToggle = null;
 
-    protected $allowToCustomizeColumns = true;
+    protected bool $allowToCustomizeColumns = true;
 
     public function __construct($db, ?Url $url = null)
     {
@@ -46,7 +43,7 @@ public function __construct($db, ?Url $url = null)
         }
     }
 
-    public function chooseColumns(array $columnNames)
+    public function chooseColumns(array $columnNames): static
     {
         $this->assertInitialized();
         if ($columnNames === ['___ALL___']) {
@@ -66,7 +63,7 @@ public function chooseColumns(array $columnNames)
         return $this;
     }
 
-    public function getColumnsToBeRendered()
+    public function getColumnsToBeRendered(): array
     {
         return $this->getChosenTitles();
     }
@@ -74,12 +71,12 @@ public function getColumnsToBeRendered()
     /**
      * @return TableColumn[]
      */
-    public function getAvailableColumns()
+    public function getAvailableColumns(): array
     {
         return $this->availableColumns;
     }
 
-    public function hasColumn($name)
+    public function hasColumn(string $name): bool
     {
         return array_key_exists($name, $this->availableColumns);
     }
@@ -95,15 +92,15 @@ public function getAvailableColumn(string $alias): TableColumn
     {
         if (array_key_exists($alias, $this->availableColumns)) {
             return $this->availableColumns[$alias];
-        } else {
-            throw new InvalidArgumentException(sprintf('No column named "%s" is available', $alias));
         }
+
+        throw new InvalidArgumentException(sprintf('No column named "%s" is available', $alias));
     }
 
-    public function assertInitialized()
+    public function assertInitialized(): void
     {
         if ($this->isInitialized === null) {
-            throw new \RuntimeException('Table initialization loop, this is a bug in your table');
+            throw new RuntimeException('Table initialization loop, this is a bug in your table');
         }
         if ($this->isInitialized === false) {
             $this->isInitialized = null;
@@ -112,36 +109,33 @@ public function assertInitialized()
         }
     }
 
-    public function nextHeader()
+    public function nextHeader(): HtmlElement
     {
-        return parent::nextHeader()->setAttributes([
-            'data-base-target' => '_self'
-        ]);
+        return parent::nextHeader()->setAttributes(['data-base-target' => '_self']);
     }
 
-    protected function renderTitleColumns()
+    protected function renderTitleColumns(): ?HtmlElement
     {
         $columns = $this->getColumnsToBeRendered();
-        if (isset($columns) && count($columns)) {
+        if (count($columns)) {
             if ($this->baseUrl) {
-                $tr = $this::tr()->setAttributes([
-                    'data-base-target' => '_self'
-                ]);
+                $tr = $this::tr()->setAttributes(['data-base-target' => '_self']);
                 $this->addSortHeadersTo($tr);
             } else {
                 $tr = $this::row($columns, null, 'th');
             }
+
             return $tr;
-        } else {
-            return null;
         }
+
+        return null;
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
     }
 
-    protected function getChosenColumns()
+    protected function getChosenColumns(): ?array
     {
         $this->assertInitialized();
         // TODO: I do not want to call this:
@@ -150,12 +144,12 @@ protected function getChosenColumns()
         return $this->chosenColumns;
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return array_keys($this->getAvailableColumns());
     }
 
-    public function getChosenColumnNames()
+    public function getChosenColumnNames(): array
     {
         $this->assertInitialized();
         if ($this->chosenColumns === null) {
@@ -165,7 +159,7 @@ public function getChosenColumnNames()
         return array_keys($this->chosenColumns);
     }
 
-    protected function getChosenTitles()
+    protected function getChosenTitles(): array
     {
         $titles = [];
 
@@ -176,14 +170,14 @@ protected function getChosenTitles()
         return $titles;
     }
 
-    protected function getRequiredDbColumns()
+    protected function getRequiredDbColumns(): array
     {
         $columns = [];
 
         foreach ($this->getChosenColumns() as $column) {
             foreach ($column->getRequiredDbColumns() as $alias => $dbExpression) {
                 if (isset($columns[$alias]) && $columns[$alias] !== $dbExpression) {
-                    throw new \RuntimeException(sprintf(
+                    throw new RuntimeException(sprintf(
                         'Setting the same table alias twice, once for %s and once for %s',
                         $columns[$alias],
                         $dbExpression
@@ -210,7 +204,7 @@ public function renderRow($row)
         return $tr;
     }
 
-    public function addAvailableColumn(TableColumn $column)
+    public function addAvailableColumn(TableColumn $column): static
     {
         $this->availableColumns[$column->getAlias()] = $column;
 
@@ -219,9 +213,10 @@ public function addAvailableColumn(TableColumn $column)
 
     /**
      * @param TableColumn[] $columns
+     *
      * @return $this
      */
-    public function addAvailableColumns($columns)
+    public function addAvailableColumns(array $columns): static
     {
         foreach ($columns as $column) {
             $this->addAvailableColumn($column);
@@ -230,51 +225,47 @@ public function addAvailableColumns($columns)
         return $this;
     }
 
-    protected function createColumn($alias, $title = null, $column = null)
-    {
+    protected function createColumn(
+        string $alias,
+        ?string $title = null,
+        array|string|null $column = null
+    ): SimpleColumn {
         return new SimpleColumn($alias, $title, $column);
     }
 
     /**
      * @param Url $url
      * @param string $sortParam
+     *
      * @return $this
      */
-    public function handleUrl(Url $url, $sortParam = 'sort')
+    public function handleUrl(Url $url, string $sortParam = 'sort'): static
     {
         if ($this->isInitialized) {
-            throw new \RuntimeException('Sort Url is late');
+            throw new RuntimeException('Sort Url is late');
         }
         $this->assertInitialized();
         $this->prepareColumnToggle($url);
 
         $this->sortParam = $sortParam;
         $this->baseUrl = $url;
-        $sort = $url->getParam($sortParam);
-        if (null === $sort) {
-            $this->sortBy($this->getDefaultSortColumns());
-        } else {
-            $this->sortBy($sort);
-        }
+        $this->sortBy($url->getParam($sortParam) ?? $this->getDefaultColumnNames());
 
         return $this;
     }
 
-    protected function getDefaultSortColumns()
+    protected function getDefaultSortColumns(): array|string
     {
-        $columns = $this->getChosenColumnNames();
-        return $columns[0];
+        return $this->getChosenColumnNames()[0];
     }
 
     /**
-     * @param string|array $columns
+     * @param array|string $columns
+     *
      * @return $this
      */
-    public function sortBy($columns)
+    public function sortBy(array|string $columns): static
     {
-        if ($columns === null) {
-            return $this;
-        }
         $this->assertInitialized();
         if (! is_array($columns)) {
             $columns = [$columns];
@@ -306,11 +297,11 @@ public function sortBy($columns)
         return $this;
     }
 
-    protected function addSortIcon(TableColumn $column, BaseHtmlElement $element)
+    protected function addSortIcon(TableColumn $column, BaseHtmlElement $element): BaseHtmlElement
     {
         $icons = [
             'ASC'  => 'up-dir',
-            'DESC' => 'down-dir',
+            'DESC' => 'down-dir'
         ];
         if (array_key_exists($column->getAlias(), $this->sortColums)) {
             $element->add(Icon::create($icons[$this->sortColums[$column->getAlias()]]));
@@ -319,7 +310,7 @@ protected function addSortIcon(TableColumn $column, BaseHtmlElement $element)
         return $element;
     }
 
-    protected function getNextSortLinkString(TableColumn $column)
+    protected function getNextSortLinkString(TableColumn $column): string
     {
         $string = $column->getAlias();
         if (array_key_exists($column->getAlias(), $this->sortColums)) {
@@ -333,18 +324,19 @@ protected function getNextSortLinkString(TableColumn $column)
 
         if ($column->getDefaultSortDirection() === 'ASC') {
             return $string;
-        } else {
-            return "$string DESC";
         }
+
+        return "$string DESC";
     }
 
     /**
      * TODO: we should consider introducing TablePlugins for similar tasks
      *
      * @param HtmlElement $parent
+     *
      * @return HtmlElement
      */
-    protected function addSortHeadersTo(HtmlElement $parent)
+    protected function addSortHeadersTo(HtmlElement $parent): HtmlElement
     {
         // Hint: MUST be set
         $url = $this->baseUrl;
@@ -365,13 +357,13 @@ protected function addSortHeadersTo(HtmlElement $parent)
 
         if ($this->columnToggle !== null && $lastTh !== null) {
             $lastTh->add(Html::tag('ul', ['class' => 'nav'], $this->columnToggle));
-            $lastTh->addAttributes(['class' => 'with-column-selector']);
+            $lastTh->addAttributes(Attributes::create(['class' => 'with-column-selector']));
         }
 
         return $parent;
     }
 
-    protected function prepareColumnToggle($url)
+    protected function prepareColumnToggle(Url $url): void
     {
         if ($this->allowToCustomizeColumns) {
             $this->columnToggle = (new ToggleTableColumns($this, $url))->ensureAssembled();
diff --git a/library/Vspheredb/Web/Table/ControlSocketConnectionsTable.php b/library/Vspheredb/Web/Table/ControlSocketConnectionsTable.php
index e668fa7b..fa59e66d 100644
--- a/library/Vspheredb/Web/Table/ControlSocketConnectionsTable.php
+++ b/library/Vspheredb/Web/Table/ControlSocketConnectionsTable.php
@@ -3,12 +3,14 @@
 namespace Icinga\Module\Vspheredb\Web\Table;
 
 use gipfl\IcingaWeb2\Icon;
+use ipl\Html\Attributes;
+use ipl\Html\HtmlElement;
 
 class ControlSocketConnectionsTable extends ArrayTable
 {
     protected $searchColumns = [
         'username',
-        'socket',
+        'socket'
     ];
 
     /* Sample Row:
@@ -31,7 +33,7 @@ class ControlSocketConnectionsTable extends ArrayTable
     }
     */
 
-    protected $myPid;
+    protected int $myPid;
 
     public function __construct($rows)
     {
@@ -39,15 +41,13 @@ public function __construct($rows)
         $this->myPid = posix_getpid();
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $tr = $this::row([
             [
-                $row->direction === 'in' ? Icon::create('endtime', [
-                    'title' => $this->translate('Incoming connection'),
-                ]) : Icon::create('starttime', [
-                    'title' => $this->translate('Outgoing connection'),
-                ]),
+                $row->direction === 'in'
+                    ? Icon::create('endtime', ['title' => $this->translate('Incoming connection')])
+                    : Icon::create('starttime', ['title' => $this->translate('Outgoing connection')]),
                 ' ',
                 $row->socket
             ],
@@ -55,18 +55,18 @@ public function renderRow($row)
             $row->pid
         ]);
         if ($row->pid === $this->myPid) {
-            $tr->addAttributes(['class' => 'control-socket-connections-table-row']);
+            $tr->addAttributes(Attributes::create(['class' => 'control-socket-connections-table-row']));
         }
 
         return $tr;
     }
 
-    public function getColumnsToBeRendered()
+    public function getColumnsToBeRendered(): array
     {
         return [
             $this->translate('Socket'),
             $this->translate('User'),
-            $this->translate('Client PID'),
+            $this->translate('Client PID')
         ];
     }
 }
diff --git a/library/Vspheredb/Web/Table/Dependency/DependencyInfoTable.php b/library/Vspheredb/Web/Table/Dependency/DependencyInfoTable.php
deleted file mode 100644
index c27688a7..00000000
--- a/library/Vspheredb/Web/Table/Dependency/DependencyInfoTable.php
+++ /dev/null
@@ -1,101 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Web\Table\Dependency;
-
-use Icinga\Application\Modules\Module;
-use Icinga\Module\Vspheredb\Application\DependencyChecker;
-use Icinga\Web\Url;
-
-class DependencyInfoTable
-{
-    protected $module;
-
-    protected $checker;
-
-    public function __construct(DependencyChecker $checker, Module $module)
-    {
-        $this->module = $module;
-        $this->checker = $checker;
-    }
-
-    protected function linkToModule($name, $icon)
-    {
-        return Html::link(
-            Html::escape($name),
-            Html::webUrl('config/module', ['name' => $name]),
-            [
-                'class' => "icon-$icon"
-            ]
-        );
-    }
-
-    public function render()
-    {
-        $html = '<table class="common-table table-row-selectable">
-<thead>
-<tr>
-    <th>' . Html::escape($this->translate('Module name')) . '</th>
-    <th>' . Html::escape($this->translate('Required')) . '</th>
-    <th>' . Html::escape($this->translate('Installed')) . '</th>
-</tr>
-</thead>
-<tbody data-base-target="_next">
-';
-        foreach ($this->checker->getDependencies($this->module) as $dependency) {
-            $name = $dependency->getName();
-            $isLibrary = substr($name, 0, 11) === 'icinga-php-';
-            $rowAttributes = $isLibrary ? ['data-base-target' => '_self'] : null;
-            if ($dependency->isSatisfied()) {
-                if ($dependency->isSatisfied()) {
-                    $icon = 'ok';
-                } else {
-                    $icon = 'cancel';
-                }
-                $link = $isLibrary ? $this->noLink($name, $icon) : $this->linkToModule($name, $icon);
-                $installed = $dependency->getInstalledVersion();
-            } elseif ($dependency->isInstalled()) {
-                $installed = sprintf('%s (%s)', $dependency->getInstalledVersion(), $this->translate('disabled'));
-                $link = $this->linkToModule($name, 'cancel');
-            } else {
-                $installed = $this->translate('missing');
-                $repository = $isLibrary ? $name : "icingaweb2-module-$name";
-                $link = sprintf(
-                    '%s (%s)',
-                    $this->noLink($name, 'cancel'),
-                    Html::linkToGitHub(Html::escape($this->translate('more')), 'Icinga', $repository)
-                );
-            }
-
-            $html .= $this->htmlRow([
-                $link,
-                Html::escape($dependency->getRequirement()),
-                Html::escape($installed)
-            ], $rowAttributes);
-        }
-
-        return $html . '</tbody>
-</table>
-';
-    }
-
-    protected function noLink($label, $icon)
-    {
-        return Html::link(Html::escape($label), Url::fromRequest()->with('rnd', rand(1, 100000)), [
-            'class' => "icon-$icon"
-        ]);
-    }
-
-    protected function translate($string)
-    {
-        return \mt('director', $string);
-    }
-
-    protected function htmlRow(array $cols, $rowAttributes)
-    {
-        $content = '';
-        foreach ($cols as $escapedContent) {
-            $content .= Html::tag('td', null, $escapedContent);
-        }
-        return Html::tag('tr', $rowAttributes, $content);
-    }
-}
diff --git a/library/Vspheredb/Web/Table/Dependency/Html.php b/library/Vspheredb/Web/Table/Dependency/Html.php
deleted file mode 100644
index b66deb73..00000000
--- a/library/Vspheredb/Web/Table/Dependency/Html.php
+++ /dev/null
@@ -1,74 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Web\Table\Dependency;
-
-use Icinga\Web\Url;
-use InvalidArgumentException;
-
-/**
- * Minimal HTML helper, as we might be forced to run without ipl
- */
-class Html
-{
-    public static function tag($tag, $attributes = [], $escapedContent = null)
-    {
-        $result = "<$tag";
-        if (! empty($attributes)) {
-            foreach ($attributes as $name => $value) {
-                if (! preg_match('/^[a-z][a-z0-9:-]*$/i', $name)) {
-                    throw new InvalidArgumentException("Invalid attribute name: '$name'");
-                }
-
-                $result .= " $name=\"" . self::escapeAttributeValue($value) . '"';
-            }
-        }
-
-        return "$result>$escapedContent</$tag>";
-    }
-
-    public static function webUrl($path, $params)
-    {
-        return Url::fromPath($path, $params);
-    }
-
-    public static function link($escapedLabel, $url, $attributes = [])
-    {
-        return static::tag('a', [
-            'href' => $url,
-        ] + $attributes, $escapedLabel);
-    }
-
-    public static function linkToGitHub($escapedLabel, $namespace, $repository)
-    {
-        return static::link(
-            $escapedLabel,
-            'https://github.com/' . urlencode($namespace) . '/' . urlencode($repository),
-            [
-                'target' => '_blank',
-                'rel'    => 'noreferrer',
-                'class'  => 'icon-forward'
-            ]
-        );
-    }
-
-    protected static function escapeAttributeValue($value)
-    {
-        $value = str_replace('"', '&quot;', $value);
-        // Escape ambiguous ampersands
-        return preg_replace_callback('/&[0-9A-Z]+;/i', function ($match) {
-            $subject = $match[0];
-
-            if (htmlspecialchars_decode($subject, ENT_COMPAT | ENT_HTML5) === $subject) {
-                // Ambiguous ampersand
-                return str_replace('&', '&amp;', $subject);
-            }
-
-            return $subject;
-        }, $value);
-    }
-
-    public static function escape($any)
-    {
-        return htmlspecialchars($any);
-    }
-}
diff --git a/library/Vspheredb/Web/Table/EventHistoryTable.php b/library/Vspheredb/Web/Table/EventHistoryTable.php
index baf03acd..0d36b099 100644
--- a/library/Vspheredb/Web/Table/EventHistoryTable.php
+++ b/library/Vspheredb/Web/Table/EventHistoryTable.php
@@ -11,33 +11,37 @@
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\Util;
+use ipl\Html\Attributes;
 use ipl\Html\DeferredText;
+use ipl\Html\FormattedString;
 use ipl\Html\Html;
 use ipl\Html\HtmlDocument;
+use ipl\Html\HtmlElement;
 use ipl\Html\HtmlString;
 use ipl\Html\Text;
 use Ramsey\Uuid\Uuid;
 use Ramsey\Uuid\UuidInterface;
+use Zend_Db_Select;
 
 class EventHistoryTable extends ZfQueryBasedTable
 {
     protected $defaultAttributes = [
         'class' => ['common-table', 'event-history-table'],
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    protected $requiredUuids = [];
+    protected array $requiredUuids = [];
 
-    protected $vMotionEvents = [
+    protected array $vMotionEvents = [
         'VmFailedMigrateEvent',
         'MigrationEvent',
         'VmBeingMigratedEvent',
         'VmBeingHotMigratedEvent',
         'VmEmigratingEvent',
-        'VmMigratedEvent',
+        'VmMigratedEvent'
     ];
 
-    protected $otherKnownEvents = [
+    protected array $otherKnownEvents = [
         'VmStartingEvent',
         'VmPoweredOnEvent',
         'VmStoppingEvent',
@@ -54,24 +58,19 @@ class EventHistoryTable extends ZfQueryBasedTable
         'VmCloneFailedEvent'
     ];
 
-    protected $fetchedUuids;
+    protected ?array $fetchedUuids = null;
 
-    /** @var Datastore */
-    protected $datastore;
+    protected ?Datastore $datastore = null;
 
-    /** @var HostSystem */
-    protected $host;
+    protected ?HostSystem $host = null;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected ?VirtualMachine $vm = null;
 
-    /** @var string */
-    protected $eventType;
+    protected string|array|null $eventType = null;
 
-    /** @var ?UuidInterface */
-    protected $parent;
+    protected ?UuidInterface $parent = null;
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $this->renderDayIfNew($row->ts_event_ms / 1000);
         $content = [];
@@ -96,113 +95,57 @@ public function renderRow($row)
         } elseif (in_array($row->event_type, $this->otherKnownEvents)) {
             $content[] = new HtmlString(nl2br(new Text($row->full_message)));
         }
-        $tr = $this::row([
-            $content,
-            DateFormatter::formatTime($row->ts_event_ms / 1000)
-        ]);
-
-        switch ($row->event_type) {
-            case 'VmFailedMigrateEvent':
-            case 'VmBeingClonedNoFolderEvent':
-            case 'VmCloneFailedEvent':
-                $tr->addAttributes([
-                    'class' => 'state migration-failed',
-                ]);
-                break;
-            case 'DrsVmMigratedEvent':
-            case 'VmMigratedEvent':
-                $tr->addAttributes([
-                    'class' => 'state migrated',
-                ]);
-                break;
-            case 'VmBeingMigratedEvent':
-            case 'VmBeingHotMigratedEvent':
-                $tr->addAttributes([
-                    'class' => 'state migrating',
-                ]);
-                break;
-            case 'VmEmigratingEvent':
-                $tr->addAttributes([
-                    'class' => 'state emigrating',
-                ]);
-                break;
-            case 'VmResettingEvent':
-            case 'VmPoweredOffEvent':
-                $tr->addAttributes([
-                    'class' => 'state poweredOff',
-                ]);
-                break;
-            case 'VmStartingEvent':
-                $tr->addAttributes([
-                    'class' => 'state starting',
-                ]);
-                break;
-            case 'VmPoweredOnEvent':
-                $tr->addAttributes([
-                    'class' => 'state poweredOn',
-                ]);
-                break;
-            case 'VmStoppingEvent':
-                $tr->addAttributes([
-                    'class' => 'state stopping',
-                ]);
-                break;
-            case 'VmSuspendedEvent':
-                $tr->addAttributes([
-                    'class' => 'event suspended',
-                ]);
-                break;
-            case 'VmReconfiguredEvent':
-            case 'VmClonedEvent':
-            case 'VmBeingClonedEvent':
-                $tr->addAttributes([
-                    'class' => 'event reconfigured',
-                ]);
-                break;
-            case 'VmBeingCreatedEvent':
-            case 'VmBeingDeployedEvent':
-                $tr->addAttributes([
-                    'class' => 'event being-created',
-                ]);
-                break;
-            case 'VmCreatedEvent':
-                $tr->addAttributes([
-                    'class' => 'event created',
-                ]);
-                break;
-            default:
-                $tr->add($this::td(Html::tag('pre', null, print_r($row, 1))));
+        $tr = $this::row([$content, DateFormatter::formatTime($row->ts_event_ms / 1000)]);
+
+        $class = match ($row->event_type) {
+            'VmFailedMigrateEvent', 'VmBeingClonedNoFolderEvent', 'VmCloneFailedEvent' => 'state migration-failed',
+            'DrsVmMigratedEvent', 'VmMigratedEvent'                                    => 'state migrated',
+            'VmBeingMigratedEvent', 'VmBeingHotMigratedEvent'                          => 'state migrating',
+            'VmEmigratingEvent'                                                        => 'state emigrating',
+            'VmResettingEvent', 'VmPoweredOffEvent'                                    => 'state poweredOff',
+            'VmStartingEvent'                                                          => 'state starting',
+            'VmPoweredOnEvent'                                                         => 'state poweredOn',
+            'VmStoppingEvent'                                                          => 'state stopping',
+            'VmSuspendedEvent'                                                         => 'event suspended',
+            'VmReconfiguredEvent', 'VmClonedEvent', 'VmBeingClonedEvent'               => 'event reconfigured',
+            'VmBeingCreatedEvent', 'VmBeingDeployedEvent'                              => 'event being-created',
+            'VmCreatedEvent'                                                           => 'event created',
+            default                                                                    => null
+        };
+
+        if ($class !== null) {
+            $tr->addAttributes(Attributes::create(['class' => $class]));
+        } else {
+            $tr->add($this::td(Html::tag('pre', null, print_r($row, 1))));
         }
 
-        $tr->addAttributes([
-            'title' => sprintf('%s (%s)', $row->full_message, $row->event_type)
-        ]);
-
-        return $tr;
+        return $tr->addAttributes(
+            Attributes::create(['title' => sprintf('%s (%s)', $row->full_message, $row->event_type)])
+        );
     }
 
-    public function filterVm(VirtualMachine $vm)
+    public function filterVm(VirtualMachine $vm): static
     {
         $this->vm = $vm;
 
         return $this;
     }
 
-    public function filterHost(HostSystem $host)
+    public function filterHost(HostSystem $host): static
     {
         $this->host = $host;
 
         return $this;
     }
 
-    public function filterDatastore(Datastore $datastore)
+    public function filterDatastore(Datastore $datastore): static
     {
         $this->datastore = $datastore;
 
         return $this;
     }
 
-    public function filterEventType($type)
+    public function filterEventType(string|array|null $type): static
     {
         if (is_array($type)) {
             $this->eventType = $type;
@@ -213,7 +156,7 @@ public function filterEventType($type)
         return $this;
     }
 
-    public function filterParent($uuid)
+    public function filterParent(?string $uuid): static
     {
         if ($uuid !== null && strlen($uuid)) {
             $this->parent = Uuid::fromString($uuid);
@@ -239,12 +182,12 @@ protected function getUuidName(?string $uuid): string
 
         if (array_key_exists($uuid, $this->fetchedUuids)) {
             return $this->fetchedUuids[$uuid];
-        } else {
-            return '[UNKNOWN]';
         }
+
+        return '[UNKNOWN]';
     }
 
-    protected function fetchUuidNames()
+    protected function fetchUuidNames(): void
     {
         $db = $this->db();
         if (empty($this->requiredUuids)) {
@@ -260,30 +203,30 @@ protected function fetchUuidNames()
         );
     }
 
-    protected function timeSince($ms)
+    protected function timeSince(int $ms): ?string
     {
         return DateFormatter::timeAgo($ms);
     }
 
     /**
-     * @return \Zend_Db_Select
+     * @return Zend_Db_Select
      */
-    protected function prepareQuery()
+    protected function prepareQuery(): Zend_Db_Select
     {
-        $query = $this->db()->select()->from([
-            'vh' => 'vm_event_history'
-        ], [
-            'vh.ts_event_ms',
-            'vh.event_type',
-            'vh.vm_uuid',
-            'vh.host_uuid',
-            'vh.user_name',
-            'vh.datastore_uuid',
-            'vh.destination_host_uuid',
-            'vh.destination_datastore_uuid',
-            'vh.full_message',
-            'vh.fault_reason',
-        ])->order('ts_event_ms DESC');
+        $query = $this->db()->select()
+            ->from(['vh' => 'vm_event_history'], [
+                'vh.ts_event_ms',
+                'vh.event_type',
+                'vh.vm_uuid',
+                'vh.host_uuid',
+                'vh.user_name',
+                'vh.datastore_uuid',
+                'vh.destination_host_uuid',
+                'vh.destination_datastore_uuid',
+                'vh.full_message',
+                'vh.fault_reason'
+            ])
+            ->order('ts_event_ms DESC');
 
         if (is_string($this->eventType) && strlen($this->eventType)) {
             $query->where('event_type = ?', $this->eventType);
@@ -294,8 +237,8 @@ protected function prepareQuery()
         if ($this->parent !== null) {
             $query->join(
                 ['o' => 'object'],
-                '(o.uuid = vh.vm_uuid OR o.uuid = vh.host_uuid OR o.uuid = vh.datastore_uuid)'
-                . ' AND o.parent_uuid = ' . DbUtil::quoteBinaryCompat($this->parent->getBytes(), $this->db()),
+                '(o.uuid = vh.vm_uuid OR o.uuid = vh.host_uuid OR o.uuid = vh.datastore_uuid) AND o.parent_uuid = '
+                . DbUtil::quoteBinaryCompat($this->parent->getBytes(), $this->db()),
                 []
             );
         }
@@ -317,13 +260,13 @@ protected function prepareQuery()
         return $query;
     }
 
-    protected function deferredVMotionPath($row)
+    protected function deferredVMotionPath(object $row): DeferredText
     {
         $properties = [
             'host_uuid',
             'destination_host_uuid',
             'datastore_uuid',
-            'destination_datastore_uuid',
+            'destination_datastore_uuid'
         ];
         foreach ($properties as $property) {
             if ($row->$property !== null) {
@@ -331,11 +274,7 @@ protected function deferredVMotionPath($row)
             }
         }
 
-        $content = new DeferredText(function () use ($row) {
-            return $this->showMotionPath($row);
-        });
-
-        return $content->setEscaped();
+        return (new DeferredText(fn() => $this->showMotionPath($row)))->setEscaped();
     }
 
     /**
@@ -347,18 +286,15 @@ protected function deferredObjectName(?string $uuid): DeferredText
     {
         $this->requiredUuids[$uuid ?? ''] = $uuid;
 
-        $content = new DeferredText(function () use ($uuid) {
-            return $this->getUuidName($uuid);
-        });
-
-        return $content->setEscaped();
+        return (new DeferredText(fn() => $this->getUuidName($uuid)))->setEscaped();
     }
 
     /**
-     * @param $row
+     * @param object $row
+     *
      * @return HtmlDocument
      */
-    protected function showMotionPath($row)
+    protected function showMotionPath(object $row): HtmlDocument
     {
         $html = new HtmlDocument();
         if ($row->host_uuid !== $row->destination_host_uuid) {
@@ -393,10 +329,11 @@ protected function showMotionPath($row)
     }
 
     /**
-     * @param $row
-     * @return \ipl\Html\FormattedString
+     * @param object $row
+     *
+     * @return FormattedString
      */
-    protected function showHostToHostMigration($row)
+    protected function showHostToHostMigration(object $row): FormattedString
     {
         if ($row->event_type === 'VmEmigratingEvent') {
             return Html::sprintf(
@@ -408,29 +345,30 @@ protected function showHostToHostMigration($row)
                 ),
                 Icon::create('right-big')
             );
-        } else {
-            return Html::sprintf(
-                '%s %s %s',
-                Link::create(
-                    $this->getUuidName($row->host_uuid),
-                    'vspheredb/host',
-                    ['uuid' => Util::niceUuid($row->host_uuid)]
-                ),
-                Icon::create('right-big'),
-                Link::create(
-                    $this->getUuidName($row->destination_host_uuid),
-                    'vspheredb/host',
-                    ['uuid' => Util::niceUuid($row->destination_host_uuid)]
-                )
-            );
         }
+
+        return Html::sprintf(
+            '%s %s %s',
+            Link::create(
+                $this->getUuidName($row->host_uuid),
+                'vspheredb/host',
+                ['uuid' => Util::niceUuid($row->host_uuid)]
+            ),
+            Icon::create('right-big'),
+            Link::create(
+                $this->getUuidName($row->destination_host_uuid),
+                'vspheredb/host',
+                ['uuid' => Util::niceUuid($row->destination_host_uuid)]
+            )
+        );
     }
 
     /**
-     * @param $row
-     * @return \ipl\Html\FormattedString
+     * @param object $row
+     *
+     * @return FormattedString
      */
-    protected function showDatastoreToDatastoreMigration($row)
+    protected function showDatastoreToDatastoreMigration(object $row): FormattedString
     {
         return Html::sprintf(
             '%s %s %s',
@@ -449,10 +387,11 @@ protected function showDatastoreToDatastoreMigration($row)
     }
 
     /**
-     * @param $row
-     * @return \ipl\Html\FormattedString
+     * @param object $row
+     *
+     * @return FormattedString
      */
-    protected function showToDatastoreMigration($row)
+    protected function showToDatastoreMigration(object $row): FormattedString
     {
         return Html::sprintf(
             '%s %s',
@@ -466,10 +405,11 @@ protected function showToDatastoreMigration($row)
     }
 
     /**
-     * @param $row
-     * @return \ipl\Html\FormattedString
+     * @param object $row
+     *
+     * @return FormattedString
      */
-    protected function showFromDatastoreMigration($row)
+    protected function showFromDatastoreMigration(object $row): FormattedString
     {
         return Html::sprintf(
             '%s %s',
@@ -483,10 +423,11 @@ protected function showFromDatastoreMigration($row)
     }
 
     /**
-     * @param $row
-     * @return \ipl\Html\FormattedString
+     * @param object $row
+     *
+     * @return FormattedString
      */
-    protected function showToHostMigration($row)
+    protected function showToHostMigration(object $row): FormattedString
     {
         return Html::sprintf(
             '%s %s',
@@ -500,10 +441,11 @@ protected function showToHostMigration($row)
     }
 
     /**
-     * @param $row
-     * @return \ipl\Html\FormattedString
+     * @param object $row
+     *
+     * @return FormattedString
      */
-    protected function showFromHostMigration($row)
+    protected function showFromHostMigration(object $row): FormattedString
     {
         return Html::sprintf(
             '%s %s',
diff --git a/library/Vspheredb/Web/Table/HostHbaTable.php b/library/Vspheredb/Web/Table/HostHbaTable.php
index f972e01f..b231c90d 100644
--- a/library/Vspheredb/Web/Table/HostHbaTable.php
+++ b/library/Vspheredb/Web/Table/HostHbaTable.php
@@ -3,23 +3,24 @@
 namespace Icinga\Module\Vspheredb\Web\Table;
 
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
-use Icinga\Module\Vspheredb\Format;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
+use ipl\Html\FormattedString;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class HostHbaTable extends ZfQueryBasedTable
 {
     protected $defaultAttributes = [
         'class' => 'common-table',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    /** @var HostSystem */
-    protected $host;
+    protected HostSystem $host;
 
-    /** @var string */
-    protected $moref;
+    protected ?string $moref = null;
 
     public function __construct(HostSystem $host)
     {
@@ -27,7 +28,7 @@ public function __construct(HostSystem $host)
         $this->moref = $this->host->object()->get('moref');
         parent::__construct($host->getConnection());
 
-        $this->prepend(new SubTitle(\sprintf(
+        $this->prepend(new SubTitle(sprintf(
             $this->translate('HBA (%s)'),
             // Hint: we could also count given HBAs, but this helps to spot
             // eventual inconsistencies
@@ -35,7 +36,7 @@ public function __construct(HostSystem $host)
         ), 'sitemap'));
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $attributes = [];
         if ($row->status !== 'online') {
@@ -45,7 +46,7 @@ public function renderRow($row)
         return $this::row([$this->formatSimple($row)], $attributes);
     }
 
-    protected function formatSimple($row)
+    protected function formatSimple(object $row): FormattedString
     {
         return Html::sprintf(
             '%s (%s: %s), %s: %s',
@@ -57,20 +58,10 @@ protected function formatSimple($row)
         );
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['hh' => 'host_hba'],
-            [
-                'hh.hba_key',
-                'hh.device',
-                'hh.driver',
-                'hh.status',
-                'hh.model',
-                'hh.pci',
-            ]
-        )->where('hh.host_uuid = ?', $this->host->get('uuid'))->order('hh.device ASC');
-
-        return $query;
+        return $this->db()->select()
+            ->from(['hh' => 'host_hba'], ['hh.hba_key', 'hh.device', 'hh.driver', 'hh.status', 'hh.model', 'hh.pci'])
+            ->where('hh.host_uuid = ?', $this->host->get('uuid'))->order('hh.device ASC');
     }
 }
diff --git a/library/Vspheredb/Web/Table/HostPciDevicesTable.php b/library/Vspheredb/Web/Table/HostPciDevicesTable.php
index 34ece0f8..19b5dcfd 100644
--- a/library/Vspheredb/Web/Table/HostPciDevicesTable.php
+++ b/library/Vspheredb/Web/Table/HostPciDevicesTable.php
@@ -3,13 +3,16 @@
 namespace Icinga\Module\Vspheredb\Web\Table;
 
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class HostPciDevicesTable extends ZfQueryBasedTable
 {
     protected $defaultAttributes = [
         'class' => 'common-table',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
     protected $searchColumns = [
@@ -18,37 +21,36 @@ class HostPciDevicesTable extends ZfQueryBasedTable
         'device_name'
     ];
 
-    /** @var HostSystem */
-    protected $host;
+    protected ?HostSystem $host = null;
 
-    public function getColumnsToBeRendered()
+    public function getColumnsToBeRendered(): array
     {
         return [
             $this->translate('ID'),
-            $this->translate('Device (Vendor)'),
+            $this->translate('Device (Vendor)')
         ];
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         return static::row([
             $row->id,
-            sprintf('%s (%s)', $row->device_name, $row->vendor_name),
+            sprintf('%s (%s)', $row->device_name, $row->vendor_name)
         ]);
     }
 
-    public function filterHost(HostSystem $host)
+    public function filterHost(HostSystem $host): static
     {
         $this->host = $host;
 
         return $this;
     }
 
-    protected function prepareQuery()
+    protected function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from([
-            'hpd' => 'host_pci_device'
-        ])->order('id ASC')->limit(1000);
+        $query = $this->db()->select()
+            ->from(['hpd' => 'host_pci_device'])
+            ->order('id ASC')->limit(1000);
 
         if ($this->host) {
             $query->where('host_uuid = ?', $this->host->get('uuid'));
diff --git a/library/Vspheredb/Web/Table/HostPhysicalNicTable.php b/library/Vspheredb/Web/Table/HostPhysicalNicTable.php
index 1fbfccac..8e90501f 100644
--- a/library/Vspheredb/Web/Table/HostPhysicalNicTable.php
+++ b/library/Vspheredb/Web/Table/HostPhysicalNicTable.php
@@ -3,25 +3,27 @@
 namespace Icinga\Module\Vspheredb\Web\Table;
 
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\Format;
 use Icinga\Module\Vspheredb\Web\Widget\MacAddress;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
+use ipl\Html\FormattedString;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class HostPhysicalNicTable extends ZfQueryBasedTable
 {
     protected $defaultAttributes = [
         'class' => 'common-table',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    /** @var HostSystem */
-    protected $host;
+    protected HostSystem $host;
 
-    /** @var string */
-    protected $moref;
+    protected ?string $moref = null;
 
     public function __construct(HostSystem $host)
     {
@@ -29,7 +31,7 @@ public function __construct(HostSystem $host)
         $this->moref = $this->host->object()->get('moref');
         parent::__construct($host->getConnection());
 
-        $this->prepend(new SubTitle(\sprintf(
+        $this->prepend(new SubTitle(sprintf(
             $this->translate('Network Interfaces (%s)'),
             // Hint: we could also count given NICs, but this helps to spot
             // eventual inconsistencies
@@ -37,7 +39,7 @@ public function __construct(HostSystem $host)
         ), 'sitemap'));
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $attributes = [];
         if ($row->link_speed_mb === null) {
@@ -46,12 +48,12 @@ public function renderRow($row)
         return $this::row([$this->formatSimple($row)], $attributes);
     }
 
-    protected function formatSimple($row)
+    protected function formatSimple(object $row): FormattedString
     {
         if ($row->link_speed_mb === null) {
             $speedInfo = $this->translate('Link is down');
         } else {
-            $speedInfo = \sprintf(
+            $speedInfo = sprintf(
                 '%s %s',
                 Format::linkSpeedMb($row->link_speed_mb),
                 $row->link_duplex === 'y'
@@ -70,11 +72,10 @@ protected function formatSimple($row)
         );
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['hpn' => 'host_physical_nic'],
-            [
+        return $this->db()->select()
+            ->from(['hpn' => 'host_physical_nic'], [
                 'hpn.nic_key',
                 'hpn.auto_negotiate_supported',
                 'hpn.device',
@@ -82,10 +83,8 @@ public function prepareQuery()
                 'hpn.link_speed_mb',
                 'hpn.link_duplex',
                 'hpn.mac_address',
-                'hpn.pci',
-            ]
-        )->where('hpn.host_uuid = ?', $this->host->get('uuid'))->order('hpn.device ASC');
-
-        return $query;
+                'hpn.pci'
+            ])
+            ->where('hpn.host_uuid = ?', $this->host->get('uuid'))->order('hpn.device ASC');
     }
 }
diff --git a/library/Vspheredb/Web/Table/HostSensorsTable.php b/library/Vspheredb/Web/Table/HostSensorsTable.php
index dedb5796..d175dbe8 100644
--- a/library/Vspheredb/Web/Table/HostSensorsTable.php
+++ b/library/Vspheredb/Web/Table/HostSensorsTable.php
@@ -7,40 +7,42 @@
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class HostSensorsTable extends ZfQueryBasedTable
 {
     protected $defaultAttributes = [
         'class' => 'common-table sensors-table',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
     protected $searchColumns = [
         'name',
-        'sensor_type',
+        'sensor_type'
     ];
 
-    /** @var HostSystem */
-    protected $host;
+    protected ?HostSystem $host = null;
 
-    protected $lastType;
+    protected ?string $lastType = null;
 
-    protected $summaries;
+    protected ?array $summaries = null;
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $this->renderTypeIfNew($row->sensor_type);
+
         return static::row([
             $this->renderHealthState($row->health_state),
             $row->name,
-            $this->renderCurrentMeasurement($row),
+            $this->renderCurrentMeasurement($row)
         ]);
     }
 
     /**
-     * @param $type
+     * @param string $type
      */
-    protected function renderTypeIfNew($type)
+    protected function renderTypeIfNew(string $type): void
     {
         if ($this->lastType !== $type) {
             $summary = $this->getSummaryByType($type);
@@ -54,10 +56,7 @@ protected function renderTypeIfNew($type)
             }
 
             $this->nextHeader()->add(
-                $this::th($title, [
-                    'colspan' => 3,
-                    'class'   => 'table-header-day'
-                ])
+                $this::th($title, ['colspan' => 3, 'class' => 'table-header-day'])
             );
 
             $this->lastType = $type;
@@ -65,7 +64,7 @@ protected function renderTypeIfNew($type)
         }
     }
 
-    protected function makeHealthStateBadge($state, $count)
+    protected function makeHealthStateBadge(string $state, int $count): Link
     {
         return Link::create($count, '#', null, ['class' => ['state', $state]]);
     }
@@ -84,26 +83,21 @@ protected function getSummaryByType(string $type): array
         return $this->summaries[$type];
     }
 
-    protected function renderHealthState($state)
+    protected function renderHealthState(string $state): Icon
     {
-        switch ($state) {
-            case 'green':
-                return Icon::create('ok', ['class' => ['state', $state]]);
-            case 'red':
-            case 'yellow':
-                return Icon::create('attention-alt', ['class' => ['state', $state]]);
-            case 'unknown':
-                return Icon::create('help', ['class' => ['state gray']]);
-            default:
-                return $state;
-        }
+        return match ($state) {
+            'green'         => Icon::create('ok', ['class' => ['state', $state]]),
+            'red', 'yellow' => Icon::create('attention-alt', ['class' => ['state', $state]]),
+            'unknown'       => Icon::create('help', ['class' => ['state gray']]),
+            default         => $state
+        };
     }
 
     public function renderSummaries()
     {
     }
 
-    protected function renderCurrentMeasurement($row)
+    protected function renderCurrentMeasurement(object $row): string
     {
         if ($row->base_units === null) {
             return '-';
@@ -116,7 +110,7 @@ protected function renderCurrentMeasurement($row)
         );
     }
 
-    public function filterHost(HostSystem $host)
+    public function filterHost(HostSystem $host): static
     {
         $this->host = $host;
 
@@ -126,22 +120,24 @@ public function filterHost(HostSystem $host)
     /**
      * @return array
      */
-    public function fetchSummaries()
+    public function fetchSummaries(): array
     {
         // Well... ROLLUP would help.
         $db = $this->db();
 
         $sums = [];
-        $query = $db->select()->from(['hs' => 'host_sensor'], [
-            'sensor_type'  => 'sensor_type',
-            'health_state' => 'health_state',
-            'cnt'          => 'COUNT(*)',
-        ])
+        $query = $db->select()
+            ->from(['hs' => 'host_sensor'], [
+                'sensor_type'  => 'sensor_type',
+                'health_state' => 'health_state',
+                'cnt'          => 'COUNT(*)'
+            ])
             ->where('base_units IS NOT NULL')
             ->group('sensor_type')
             ->group('health_state')
             ->order('sensor_type')
             ->order('health_state');
+
         if ($this->host) {
             $query->where('host_uuid = ?', $this->host->get('uuid'));
         }
@@ -154,7 +150,7 @@ public function fetchSummaries()
                     'green' => 0,
                     'yellow' => 0,
                     'unknown' => 0,
-                    'red' => 0,
+                    'red' => 0
                 ];
             }
 
@@ -165,16 +161,17 @@ public function fetchSummaries()
     }
 
     /**
-     * @return \Zend_Db_Select
+     * @return Zend_Db_Select
      */
-    protected function prepareQuery()
+    protected function prepareQuery(): Zend_Db_Select
     {
-        $query = $this->db()->select()->from([
-            'hpd' => 'host_sensor'
-        ])->order('sensor_type')->order('name')->limit(1000);
-
-        $query->where('base_units IS NOT NULL');
-        // $query->where('health_state != ?', 'unknown');
+        $query = $this->db()->select()
+            ->from(['hpd' => 'host_sensor'])
+            ->order('sensor_type')
+            ->order('name')
+            ->limit(1000)
+            ->where('base_units IS NOT NULL');
+        //    ->where('health_state != ?', 'unknown');
 
         if ($this->host) {
             $query->where('host_uuid = ?', $this->host->get('uuid'));
diff --git a/library/Vspheredb/Web/Table/MonitoredObjectMappingTable.php b/library/Vspheredb/Web/Table/MonitoredObjectMappingTable.php
index 03dd8ffe..37d13fcf 100644
--- a/library/Vspheredb/Web/Table/MonitoredObjectMappingTable.php
+++ b/library/Vspheredb/Web/Table/MonitoredObjectMappingTable.php
@@ -4,104 +4,88 @@
 
 use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Table\Extension\ZfSortablePriority;
+use gipfl\ZfDb\Select;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
+use Zend_Db_Select;
 
 class MonitoredObjectMappingTable extends BaseTable
 {
     use ZfSortablePriority;
 
-    protected $keyColumn = 'id';
+    protected string $keyColumn = 'id';
 
-    protected $priorityColumn = 'priority';
+    protected string $priorityColumn = 'priority';
 
     protected $defaultAttributes = [
         'class' => ['common-table', 'table-row-selectable'],
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             (new SimpleColumn('source', $this->translate('Source'), [
                 'source_type'          => 'mc.source_type',
                 'source_resource_name' => 'mc.source_resource_name',
                 'id'                   => 'mc.id',
-                'priority'             => 'mc.priority',
-            ]))->setRenderer(function ($row) {
-                return Link::create(sprintf(
-                    '%s: %s',
-                    $row->source_type,
-                    $row->source_resource_name
-                ), 'vspheredb/configuration/monitoringconfig', [
-                    'id' => $row->id
-                ], [
-                    'data-base-target' => '_next'
-                ]);
-            }),
+                'priority'             => 'mc.priority'
+            ]))
+                ->setRenderer(fn($row) => Link::create(
+                    sprintf('%s: %s', $row->source_type, $row->source_resource_name),
+                    'vspheredb/configuration/monitoringconfig',
+                    ['id' => $row->id],
+                    ['data-base-target' => '_next']
+                )),
+
             (new SimpleColumn('host_mapping', $this->translate('Host Mapping'), [
                 'host_property'            => 'mc.host_property',
-                'monitoring_host_property' => 'mc.monitoring_host_property',
-            ]))->setRenderer(function ($row) {
-                if ($row->host_property === null) {
-                    return null;
-                } else {
-                    return sprintf(
-                        '%s -> %s',
-                        $row->monitoring_host_property,
-                        $row->host_property
-                    );
-                }
-            }),
+                'monitoring_host_property' => 'mc.monitoring_host_property'
+            ]))
+                ->setRenderer(fn($row) => $row->host_property === null ? null : sprintf(
+                    '%s -> %s',
+                    $row->monitoring_host_property,
+                    $row->host_property
+                )),
+
             (new SimpleColumn('vm_mapping', $this->translate('VM Mapping'), [
                 'vm_property'                 => 'mc.vm_property',
-                'monitoring_vm_host_property' => 'mc.monitoring_vm_host_property',
-            ]))->setRenderer(function ($row) {
-                if ($row->host_property === null) {
-                    return null;
-                } else {
-                    return sprintf(
-                        '%s -> %s',
-                        $row->monitoring_vm_host_property,
-                        $row->vm_property
-                    );
-                }
-            }),
+                'monitoring_vm_host_property' => 'mc.monitoring_vm_host_property'
+            ]))
+                ->setRenderer(fn($row) => $row->host_property === null ? null : sprintf(
+                    '%s -> %s',
+                    $row->monitoring_vm_host_property,
+                    $row->vm_property
+                ))
         ]);
     }
 
     // cloned from ZfSortablePriority, added data-base-target
-    protected function xaddSortPriorityButtons(BaseHtmlElement $tr, $row)
+    protected function xaddSortPriorityButtons(BaseHtmlElement $tr, object $row): BaseHtmlElement
     {
-        $tr->add(
+        return $tr->add(
             Html::tag(
                 'td',
                 ['data-base-target' => '_self'],
                 $this->createUpDownButtons($row->{$this->getKeyColumn()})
             )
         );
-
-        return $tr;
     }
 
-    public function renderRow($row)
+    public function renderRow($row): BaseHtmlElement
     {
-        return $this->xaddSortPriorityButtons(
-            parent::renderRow($row),
-            $row
-        );
+        return $this->xaddSortPriorityButtons(parent::renderRow($row), $row);
     }
 
-    public function render()
+    public function render(): string
     {
         return $this->renderWithSortableForm();
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        return $this->db()->select()->from(
-            ['mc' => 'monitoring_connection'],
-            $this->getRequiredDbColumns()
-        )->order('priority');
+        return $this->db()->select()
+            ->from(['mc' => 'monitoring_connection'], $this->getRequiredDbColumns())
+            ->order('priority');
     }
 }
diff --git a/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblemHistoryTable.php b/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblemHistoryTable.php
index 275edfde..33d7d2be 100644
--- a/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblemHistoryTable.php
+++ b/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblemHistoryTable.php
@@ -4,6 +4,7 @@
 
 use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Date\DateFormatter;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
 use Icinga\Module\Vspheredb\Db\DbUtil;
@@ -13,26 +14,28 @@
 use Icinga\Module\Vspheredb\Web\Table\UuidLinkHelper;
 use Icinga\Module\Vspheredb\Web\Widget\CheckPluginHelper;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class MonitoringRuleProblemHistoryTable extends ZfQueryBasedTable implements TableWithVCenterFilter
 {
     use UuidLinkHelper;
 
-    protected $entityUuid;
+    protected ?string $entityUuid = null;
 
     protected $defaultAttributes = [
         'class' => ['common-table', 'table-row-selectable'],
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    public function filterEntityUuid($uuid)
+    public function filterEntityUuid(string $uuid): static
     {
         $this->entityUuid = $uuid;
 
         return $this;
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $this->renderDayIfNew($row->ts_changed_ms / 1000);
 
@@ -41,7 +44,7 @@ public function renderRow($row)
             $output = [
                 CheckPluginHelper::colorizeOutput($this->translate('[OK] Check has no longer been executed')),
                 ' ',
-                CheckPluginHelper::colorizeOutput($formerState),
+                CheckPluginHelper::colorizeOutput($formerState)
             ];
         } else {
             $lines = preg_split("/\r?\n/", $row->output);
@@ -49,26 +52,23 @@ public function renderRow($row)
             $output = CheckPluginHelper::colorizeOutput(implode("\n", $lines));
         }
 
-        if ($this->entityUuid) {
-            $cell[] = Html::tag('strong', $row->rule_name);
-        } else {
-            $cell[] = Html::sprintf(
+        $cell[] = $this->entityUuid
+            ? Html::tag('strong', $row->rule_name)
+            : Html::sprintf(
                 $this->translate("%s on %s"),
                 Html::tag('strong', $row->rule_name),
                 $this->linkToObject($row) // No link if entityUuid!!
             );
-        }
         $cell[] = "\n";
         $cell[] = $output;
 
-        $tr = $this::row([Html::tag('pre', [
-            'class' => 'logOutput'
-        ], $cell), DateFormatter::formatTime($row->ts_changed_ms / 1000)]);
-
-        return $tr;
+        return $this::row([
+            Html::tag('pre', ['class' => 'logOutput'], $cell),
+            DateFormatter::formatTime($row->ts_changed_ms / 1000)
+        ]);
     }
 
-    protected function linkToObject($row)
+    protected function linkToObject($row): Link
     {
         return Link::create(
             Anonymizer::anonymizeString($row->object_name),
@@ -79,37 +79,30 @@ protected function linkToObject($row)
 
     protected function getBaseUrl($row): ?string
     {
-        switch ($row->object_type) {
-            case 'HostSystem':
-                return 'vspheredb/host';
-            case 'VirtualMachine':
-                return 'vspheredb/vm';
-            case 'Datastore':
-                return 'vspheredb/datastore';
-            default:
-                return null;
-        }
+        return match ($row->object_type) {
+            'HostSystem'     => 'vspheredb/host',
+            'VirtualMachine' => 'vspheredb/vm',
+            'Datastore'      => 'vspheredb/datastore',
+            default          => null
+        };
     }
 
-    protected function prepareQuery()
+    protected function prepareQuery(): Select|Zend_Db_Select
     {
         // uuid, current_state, former_state, rule_name, ts_changed_ms, output
-        $query = $this->db()->select()->from([
-            'ph' => 'monitoring_rule_problem_history'
-        ], [
-            'o.object_name',
-            'o.object_type',
-            'ph.uuid',
-            'ph.current_state',
-            'ph.former_state',
-            'ph.rule_name',
-            'ph.ts_changed_ms',
-            'ph.output',
-        ])->join(
-            ['o' => 'object'],
-            'o.uuid = ph.uuid',
-            []
-        )->order('ts_changed_ms DESC');
+        $query = $this->db()->select()
+            ->from(['ph' => 'monitoring_rule_problem_history'], [
+                'o.object_name',
+                'o.object_type',
+                'ph.uuid',
+                'ph.current_state',
+                'ph.former_state',
+                'ph.rule_name',
+                'ph.ts_changed_ms',
+                'ph.output'
+            ])
+            ->join(['o' => 'object'], 'o.uuid = ph.uuid', [])
+            ->order('ts_changed_ms DESC');
 
         if ($this->entityUuid !== null) {
             $query->where('ph.uuid = ?', $this->entityUuid);
@@ -118,15 +111,16 @@ protected function prepareQuery()
         return $query;
     }
 
-    public function filterVCenter(VCenter $vCenter): self
+    public function filterVCenter(VCenter $vCenter): static
     {
         return $this->filterVCenterUuids([$vCenter->getUuid()]);
     }
 
-    public function filterVCenterUuids(array $uuids): self
+    public function filterVCenterUuids(array $uuids): static
     {
         if (empty($uuids)) {
             $this->getQuery()->where('1 = 0');
+
             return $this;
         }
 
diff --git a/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblemTable.php b/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblemTable.php
index eea972be..60131b25 100644
--- a/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblemTable.php
+++ b/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblemTable.php
@@ -4,25 +4,27 @@
 
 use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Db\DbUtil;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Module\Vspheredb\Util;
 use Icinga\Module\Vspheredb\Web\Table\TableWithVCenterFilter;
 use ipl\Html\Html;
+use Zend_Db_Select;
 
 class MonitoringRuleProblemTable extends ZfQueryBasedTable implements TableWithVCenterFilter
 {
-    protected $formerVCenter = null;
+    protected ?string $formerVCenter = null;
 
     public function getColumnsToBeRendered(): array
     {
         return [
             $this->translate('VCenter'),
-            $this->translate('Problems / Monitoring Rule'),
+            $this->translate('Problems / Monitoring Rule')
         ];
     }
 
-    public function renderRow($row)
+    public function renderRow($row): array
     {
         if ($row->vcenter_name === $this->formerVCenter) {
             $row->vcenter_name = null;
@@ -37,10 +39,7 @@ public function renderRow($row)
                 if (! empty($states)) {
                     $states[] = ' ';
                 }
-                $states[] = Html::tag('span', ['class' => [
-                    'badge',
-                    "state-$state"
-                ]], $row->$property);
+                $states[] = Html::tag('span', ['class' => ['badge', "state-$state"]], $row->$property);
             }
             unset($row->$property);
         }
@@ -56,22 +55,23 @@ public function renderRow($row)
             'vcenter'    => Util::niceUuid($row->vcenter_uuid),
             'objectType' => $objectType,
             'ruleSet'    => $ruleSet,
-            'rule'       => $rule,
+            'rule'       => $rule
         ])];
         unset($row->vcenter_uuid);
 
         return (array) $row;
     }
 
-    public function filterVCenter(VCenter $vCenter): self
+    public function filterVCenter(VCenter $vCenter): static
     {
         return $this->filterVCenterUuids([$vCenter->getUuid()]);
     }
 
-    public function filterVCenterUuids(array $uuids): self
+    public function filterVCenterUuids(array $uuids): static
     {
         if (empty($uuids)) {
             $this->getQuery()->where('1 = 0');
+
             return $this;
         }
 
@@ -86,30 +86,26 @@ public function filterVCenterUuids(array $uuids): self
         return $this;
     }
 
-    protected function prepareQuery()
+    protected function prepareQuery(): Select|Zend_Db_Select
     {
-        $db = $this->db();
-        return $db->select()->from(
-            ['p' => 'monitoring_rule_problem'],
-            [
-                'vcenter_uuid' => 'vc.instance_uuid',
-                'vcenter_name' => 'vc.name',
+        return $this->db()->select()
+            ->from(['p' => 'monitoring_rule_problem'], [
+                'vcenter_uuid'     => 'vc.instance_uuid',
+                'vcenter_name'     => 'vc.name',
                 // 'object_type' => 'o.object_type',
                 // 'rule_name' => 'p.rule_name',
                 'object_rule_name' => "o.object_type || '/' || p.rule_name",
-                'cnt_critical' => "SUM(CASE WHEN p.current_state = 'CRITICAL' THEN 1 ELSE 0 END)",
-                'cnt_unknown' => "SUM(CASE WHEN p.current_state = 'UNKNOWN' THEN 1 ELSE 0 END)",
-                'cnt_warning' => "SUM(CASE WHEN p.current_state = 'WARNING' THEN 1 ELSE 0 END)",
-            ]
-        )
-        ->join(['o' => 'object'], 'o.uuid = p.uuid', [])
-        ->join(['vc' => 'vcenter'], 'o.vcenter_uuid = vc.instance_uuid', [])
+                'cnt_critical'     => "SUM(CASE WHEN p.current_state = 'CRITICAL' THEN 1 ELSE 0 END)",
+                'cnt_unknown'      => "SUM(CASE WHEN p.current_state = 'UNKNOWN' THEN 1 ELSE 0 END)",
+                'cnt_warning'      => "SUM(CASE WHEN p.current_state = 'WARNING' THEN 1 ELSE 0 END)"
+            ])
+            ->join(['o' => 'object'], 'o.uuid = p.uuid', [])
+            ->join(['vc' => 'vcenter'], 'o.vcenter_uuid = vc.instance_uuid', [])
             ->group('vc.name')
             ->group('o.object_type')
             ->group('p.rule_name')
             ->order('vc.name')
             ->order('o.object_type')
-            ->order('p.rule_name')
-        ;
+            ->order('p.rule_name');
     }
 }
diff --git a/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblematicObjectTable.php b/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblematicObjectTable.php
index 9e9ed03e..988f22ed 100644
--- a/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblematicObjectTable.php
+++ b/library/Vspheredb/Web/Table/Monitoring/MonitoringRuleProblematicObjectTable.php
@@ -4,25 +4,32 @@
 
 use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
+use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\Db\DbUtil;
+use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\Monitoring\CheckRunner;
-use Icinga\Module\Vspheredb\Monitoring\MonitoringRuleLookup;
+use Icinga\Module\Vspheredb\Monitoring\Rule\Enum\ObjectType;
 use Icinga\Module\Vspheredb\Web\Widget\CheckPluginHelper;
 use ipl\Html\Html;
 use ipl\Html\HtmlString;
 use Ramsey\Uuid\Uuid;
+use Zend_Db_Select;
 
 class MonitoringRuleProblematicObjectTable extends ZfQueryBasedTable
 {
-    protected $objectType;
-    protected $ruleSet;
-    protected $rule;
-    /** @var CheckRunner */
-    protected $runner;
-    protected $vCenter;
+    protected string $objectType;
 
-    public function __construct($db, $vCenter, $objectType, $ruleSet, $rule)
+    protected string $ruleSet;
+
+    protected string $rule;
+
+    protected CheckRunner $runner;
+
+    protected VCenter $vCenter;
+
+    public function __construct(Db $db, Vcenter $vCenter, string $objectType, string $ruleSet, string $rule)
     {
         parent::__construct($db);
         $this->objectType = $objectType;
@@ -36,15 +43,14 @@ public function __construct($db, $vCenter, $objectType, $ruleSet, $rule)
 
     public function getColumnsToBeRendered(): array
     {
-        return [
-            $this->translate('Object'),
-        ];
+        return [$this->translate('Object')];
     }
 
-    public function renderRow($row)
+    public function renderRow($row): array
     {
-        $url = MonitoringRuleLookup::getUrlForObjectType($this->objectType);
-        $class = MonitoringRuleLookup::getClassForObjectType($this->objectType);
+        $type = ObjectType::fromParam($this->objectType);
+        $url = $type->url();
+        $class = $type->class();
 
         $object = $class::load($row->uuid, $this->connection());
         $result = $this->runner->check($object);
@@ -55,34 +61,30 @@ public function renderRow($row)
             }
         }
 
-        $link = Link::create($label, $url, [
-            'uuid' => Uuid::fromBytes($row->uuid)->toString()
-        ]);
+        $link = Link::create($label, $url, ['uuid' => Uuid::fromBytes($row->uuid)->toString()]);
         $output = $result->getOutput();
         $output = explode(PHP_EOL, $output);
-        $output[0] = $output[0] . ': ' . 'LINK!TO!OBJECT';
+        $output[0] .= ': LINK!TO!OBJECT';
         $output = CheckPluginHelper::colorizeOutput(implode(PHP_EOL, $output))->render();
         $output = preg_replace('/LINK!TO!OBJECT/', $link->render(), $output);
-        $output = new HtmlString($output);
 
-        return [[
-            Html::tag('pre', ['class' => 'logOutput'], $output)
-        ]];
+        return [[Html::tag('pre', ['class' => 'logOutput'], new HtmlString($output))]];
     }
 
-    protected function prepareQuery()
+    protected function prepareQuery(): Select|Zend_Db_Select
     {
-        $objectTable = MonitoringRuleLookup::getTableForObjectType($this->objectType);
+        $objectTable = ObjectType::fromParam($this->objectType)->table();
         $db = $this->db();
-        return $db->select()->from(['p' => 'monitoring_rule_problem'], [
-            'uuid'      => 'o.uuid',
-            'rule_name' => 'p.rule_name',
-        ])
-        ->where('o.vcenter_uuid = ?', DbUtil::quoteBinaryCompat($this->vCenter->get('uuid'), $db))
-        ->where('p.rule_name = ?', sprintf('%s/%s', $this->ruleSet, $this->rule))
-        ->join(['o' => 'object'], 'o.uuid = p.uuid', [])
-        ->join(['ot' => $objectTable], 'o.uuid = ot.uuid', [])
-        ->order('p.current_state DESC')
-        ->order('o.object_name');
+        return $db->select()
+            ->from(['p' => 'monitoring_rule_problem'], [
+                'uuid'      => 'o.uuid',
+                'rule_name' => 'p.rule_name'
+            ])
+            ->where('o.vcenter_uuid = ?', DbUtil::quoteBinaryCompat($this->vCenter->get('uuid'), $db))
+            ->where('p.rule_name = ?', sprintf('%s/%s', $this->ruleSet, $this->rule))
+            ->join(['o' => 'object'], 'o.uuid = p.uuid', [])
+            ->join(['ot' => $objectTable], 'o.uuid = ot.uuid', [])
+            ->order('p.current_state DESC')
+            ->order('o.object_name');
     }
 }
diff --git a/library/Vspheredb/Web/Table/Object/HostHardwareInfoTable.php b/library/Vspheredb/Web/Table/Object/HostHardwareInfoTable.php
index 1427c4ec..d0a2b1e3 100644
--- a/library/Vspheredb/Web/Table/Object/HostHardwareInfoTable.php
+++ b/library/Vspheredb/Web/Table/Object/HostHardwareInfoTable.php
@@ -15,11 +15,9 @@ class HostHardwareInfoTable extends NameValueTable
 {
     use Translation;
 
-    /** @var HostSystem */
-    protected $host;
+    protected HostSystem $host;
 
-    /** @var HostQuickStats */
-    protected $quickStats;
+    protected HostQuickStats $quickStats;
 
     public function __construct(HostSystem $host, HostQuickStats $quickStats)
     {
@@ -27,13 +25,13 @@ public function __construct(HostSystem $host, HostQuickStats $quickStats)
         $this->quickStats = $quickStats;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->prepend(new SubTitle($this->translate('Hardware Information'), 'th-thumb-empty'));
         $host = $this->host;
         $this->addNameValuePairs([
             $this->translate('CPU') => [
-                \sprintf(
+                sprintf(
                     $this->translate('%d Packages, %d Cores, %d Threads'),
                     $host->get('hardware_cpu_packages'),
                     $host->get('hardware_cpu_cores'),
@@ -50,7 +48,7 @@ protected function assemble()
                 $this->quickStats->get('overall_memory_usage_mb'),
                 $host->get('hardware_memory_size_mb')
             ),
-            $this->translate('HBAs') => $host->get('hardware_num_hba'),
+            $this->translate('HBAs') => $host->get('hardware_num_hba')
         ]);
     }
 }
diff --git a/library/Vspheredb/Web/Table/Object/HostSystemInfoTable.php b/library/Vspheredb/Web/Table/Object/HostSystemInfoTable.php
index 8d758fb4..514ec95b 100644
--- a/library/Vspheredb/Web/Table/Object/HostSystemInfoTable.php
+++ b/library/Vspheredb/Web/Table/Object/HostSystemInfoTable.php
@@ -15,20 +15,18 @@
 use Icinga\Module\Vspheredb\Web\Widget\Link\MobLink;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\I18n\Translation;
 
 class HostSystemInfoTable extends NameValueTable
 {
     use Translation;
 
-    /** @var HostSystem */
-    protected $host;
+    protected HostSystem $host;
 
-    /** @var HostQuickStats */
-    protected $quickStats;
+    protected HostQuickStats $quickStats;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     public function __construct(HostSystem $host, HostQuickStats $quickStats, VCenter $vCenter)
     {
@@ -37,7 +35,7 @@ public function __construct(HostSystem $host, HostQuickStats $quickStats, VCente
         $this->vCenter = $vCenter;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->prepend(new SubTitle($this->translate('System Information'), 'host'));
         $host = $this->host;
@@ -52,45 +50,46 @@ protected function assemble()
             $this->translate('Service Tag')  => $this->getFormattedServiceTag($host),
             $this->translate('BIOS Version') => new BiosInfo($host),
             $this->translate('Uptime')       => $this->showUptime($this->quickStats->get('uptime')),
-            $this->translate('System UUID')  => Html::tag('pre', Anonymizer::shuffleString($host->get('sysinfo_uuid'))),
+            $this->translate('System UUID')  => Html::tag('pre', Anonymizer::shuffleString($host->get('sysinfo_uuid')))
         ]);
     }
 
-    protected function showUptime($uptime)
+    protected function showUptime($uptime): array
     {
         return [
             DateFormatter::formatDuration($uptime),
             $uptime < 900 ? Icon::create('warning-empty', [
                 'class' => ['state', 'yellow'],
-                'title' => $this->translate('System booted recently'),
-            ]) : null,
+                'title' => $this->translate('System booted recently')
+            ]) : null
         ];
     }
 
     /**
      * @param HostSystem $host
-     * @return \ipl\Html\HtmlElement|mixed
+     *
+     * @return HtmlElement|mixed
      */
-    protected function getFormattedServiceTag(HostSystem $host)
+    protected function getFormattedServiceTag(HostSystem $host): mixed
     {
         if ($tag = $host->get('service_tag')) {
             $tag = Anonymizer::shuffleString($tag);
         }
         if ($this->host->get('sysinfo_vendor') === 'Dell Inc.') {
             return $this->linkToDellSupport($tag);
-        } else {
-            return $tag;
         }
+
+        return $tag;
     }
 
-    protected function prepareTools(HostSystem $host)
+    protected function prepareTools(HostSystem $host): Hint|array
     {
         $tools = [];
 
         if ($this->vCenter->getFirstServer(false, false) === null) {
             return Hint::warning($this->translate('There is no configured connection for this vCenter'));
         }
-        if (\version_compare($this->vCenter->get('api_version'), '6.5', '>=')) {
+        if (version_compare($this->vCenter->get('api_version'), '6.5', '>=')) {
             $tools[] = new Html5UiLink($this->vCenter, $host, 'HTML5 UI');
             $tools[] = ' ';
         }
@@ -99,7 +98,7 @@ protected function prepareTools(HostSystem $host)
         return $tools;
     }
 
-    protected function renderVendorModel($vendor, $model)
+    protected function renderVendorModel(?string $vendor, ?string $model): array|string|null
     {
         if ($url = $this->findVendorModel($vendor, $model)) {
             if (is_array($url)) {
@@ -134,9 +133,9 @@ protected function renderVendorModel($vendor, $model)
      * @param ?string $vendor
      * @param ?string $model
      *
-     * @return ?string
+     * @return array|string|null
      */
-    protected function findVendorModel(?string $vendor, ?string $model): ?string
+    protected function findVendorModel(?string $vendor, ?string $model): array|string|null
     {
         $images = include __DIR__ . '/known-vendor-model-images.php';
         if ($vendor === null || $model === null) {
@@ -147,7 +146,7 @@ protected function findVendorModel(?string $vendor, ?string $model): ?string
         }
         if (isset($images[$vendor])) {
             foreach ($images[$vendor] as $pattern => $url) {
-                if (substr($pattern, 0, 1) === '/' && preg_match($pattern, $model)) {
+                if (str_starts_with($pattern, '/') && preg_match($pattern, $model)) {
                     return $url;
                 }
             }
@@ -156,27 +155,22 @@ protected function findVendorModel(?string $vendor, ?string $model): ?string
         return null;
     }
 
-    protected function linkToDellSupport($serviceTag)
+    protected function linkToDellSupport(?string $serviceTag): HtmlElement|string
     {
         if ($serviceTag === null) {
             return '-';
         }
-        $urlPattern = 'http://www.dell.com/support/home/product-support/servicetag/%s/drivers';
-
-        $url = sprintf(
-            $urlPattern,
-            strtolower($serviceTag)
-        );
-
-        return Html::tag(
-            'a',
-            [
-                'href'   => $url,
-                'target' => '_blank',
-                'title'  => $this->translate('Dell Support Page'),
-                'rel'    => 'noreferrer'
-            ],
-            $serviceTag
-        );
+
+        $attributes = [
+            'href'   => sprintf(
+                'http://www.dell.com/support/home/product-support/servicetag/%s/drivers',
+                strtolower($serviceTag)
+            ),
+            'target' => '_blank',
+            'title'  => $this->translate('Dell Support Page'),
+            'rel'    => 'noreferrer'
+        ];
+
+        return Html::tag('a', $attributes, $serviceTag);
     }
 }
diff --git a/library/Vspheredb/Web/Table/Object/HostVirtualizationInfoTable.php b/library/Vspheredb/Web/Table/Object/HostVirtualizationInfoTable.php
index 008c4c8d..34ad40f2 100644
--- a/library/Vspheredb/Web/Table/Object/HostVirtualizationInfoTable.php
+++ b/library/Vspheredb/Web/Table/Object/HostVirtualizationInfoTable.php
@@ -17,15 +17,15 @@ class HostVirtualizationInfoTable extends NameValueTable
 {
     use Translation;
 
-    /** @var HostSystem */
-    protected $host;
+    protected HostSystem $host;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     /**
      * HostVirtualizationInfoTable constructor.
+     *
      * @param HostSystem $host
+     *
      * @throws NotFoundError
      */
     public function __construct(HostSystem $host)
@@ -34,7 +34,7 @@ public function __construct(HostSystem $host)
         $this->vCenter = VCenter::load($host->get('vcenter_uuid'), $host->getConnection());
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->prepend(new SubTitle($this->translate('Virtualization Information'), 'cloud'));
         $host = $this->host;
@@ -43,14 +43,14 @@ protected function assemble()
         $this->addNameValuePairs([
             $this->translate('vCenter')     => new VCenterLink($this->vCenter),
             $this->translate('Path')        => PathToObjectRenderer::render($host),
-            $this->translate('Vms') => Link::create(
+            $this->translate('Vms')         => Link::create(
                 $host->countVms(),
                 'vspheredb/host/vms',
                 Util::uuidParams($uuid)
             ),
             $this->translate('HA State')    => $host->get('das_host_state'),
             $this->translate('Hypervisor')  => $host->get('product_full_name'),
-            $this->translate('API Version') => $host->get('product_api_version'),
+            $this->translate('API Version') => $host->get('product_api_version')
         ]);
     }
 }
diff --git a/library/Vspheredb/Web/Table/Object/HostVmsInfoTable.php b/library/Vspheredb/Web/Table/Object/HostVmsInfoTable.php
deleted file mode 100644
index 3e913881..00000000
--- a/library/Vspheredb/Web/Table/Object/HostVmsInfoTable.php
+++ /dev/null
@@ -1,42 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Web\Table\Object;
-
-use gipfl\IcingaWeb2\Link;
-use gipfl\Web\Table\NameValueTable;
-use Icinga\Module\Vspheredb\DbObject\HostSystem;
-use Icinga\Module\Vspheredb\Util;
-use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
-use ipl\I18n\Translation;
-
-class HostVmsInfoTable extends NameValueTable
-{
-    use Translation;
-
-    /** @var HostSystem */
-    protected $host;
-
-    public function __construct(HostSystem $host)
-    {
-        $this->host = $host;
-        $this->prepend(new SubTitle($this->translate('Virtual Machines'), 'cubes'));
-    }
-
-    protected function getDb()
-    {
-        return $this->host->getConnection();
-    }
-
-    protected function assemble()
-    {
-        $host = $this->host;
-        $uuid = $host->get('uuid');
-        $this->addNameValuePairs([
-            $this->translate('Vms') => Link::create(
-                $host->countVms(),
-                'vspheredb/host/vms',
-                Util::uuidParams($uuid)
-            ),
-        ]);
-    }
-}
diff --git a/library/Vspheredb/Web/Table/Object/VCenterInfoTable.php b/library/Vspheredb/Web/Table/Object/VCenterInfoTable.php
deleted file mode 100644
index 69132a4b..00000000
--- a/library/Vspheredb/Web/Table/Object/VCenterInfoTable.php
+++ /dev/null
@@ -1,47 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Web\Table\Object;
-
-use gipfl\Web\Table\NameValueTable;
-use Icinga\Module\Vspheredb\DbObject\VCenter;
-use ipl\I18n\Translation;
-use Ramsey\Uuid\Uuid;
-
-class VCenterInfoTable extends NameValueTable
-{
-    use Translation;
-
-    protected $vcenter;
-
-    public function __construct(VCenter $vcenter)
-    {
-        $this->vcenter = $vcenter;
-    }
-
-    protected function assemble()
-    {
-        $c = $this->vcenter;
-
-        $this->addNameValuePairs([
-            $this->translate('Name') => $c->get('name'),
-            $this->translate('Info') => sprintf(
-                '%s %s build-%s',
-                $c->get('api_type'),
-                $c->get('version'),
-                $c->get('build')
-            ),
-            $this->translate('UUID') => Uuid::fromBytes($c->get('instance_uuid'))->toString(),
-            // $this->translate('Version') => $c->get('version'),
-            $this->translate('OS Type') => $c->get('os_type'),
-            $this->translate('API Type') => $c->get('api_type'),
-            $this->translate('API Version') => $c->get('api_version'),
-            // $this->translate('Build') => $c->get('build'),
-            $this->translate('Vendor') => $c->get('vendor'),
-            $this->translate('Product Line') => $c->get('product_line'),
-            $this->translate('license Product Name') => $c->get('license_product_name'),
-            $this->translate('license Product Version') => $c->get('license_product_version'),
-            $this->translate('Locale Build') => $c->get('locale_build'),
-            $this->translate('Locale Version') => $c->get('locale_version'),
-        ]);
-    }
-}
diff --git a/library/Vspheredb/Web/Table/Object/VmEssentialInfoTable.php b/library/Vspheredb/Web/Table/Object/VmEssentialInfoTable.php
index 5c9ee762..ea8e0382 100644
--- a/library/Vspheredb/Web/Table/Object/VmEssentialInfoTable.php
+++ b/library/Vspheredb/Web/Table/Object/VmEssentialInfoTable.php
@@ -2,18 +2,19 @@
 
 namespace Icinga\Module\Vspheredb\Web\Table\Object;
 
+use Exception;
 use gipfl\IcingaWeb2\Icon;
 use gipfl\IcingaWeb2\Link;
 use ipl\I18n\Translation;
 use gipfl\Web\Table\NameValueTable;
-use Exception;
 use gipfl\Web\Widget\Hint;
 use Icinga\Date\DateFormatter;
 use Icinga\Module\Vspheredb\Addon\IbmSpectrumProtect;
-use Icinga\Module\Vspheredb\Addon\SimpleBackupTool;
 use Icinga\Module\Vspheredb\Addon\NetBackup;
+use Icinga\Module\Vspheredb\Addon\SimpleBackupTool;
 use Icinga\Module\Vspheredb\Addon\VeeamBackup;
 use Icinga\Module\Vspheredb\Addon\VRangerBackup;
+use Icinga\Module\Vspheredb\Db\DbConnection;
 use Icinga\Module\Vspheredb\DbObject\MonitoringConnection;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
@@ -28,16 +29,15 @@
 use Icinga\Module\Vspheredb\Web\Widget\Renderer\GuestToolsVersionRenderer;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 
 class VmEssentialInfoTable extends NameValueTable
 {
     use Translation;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     public function __construct(VirtualMachine $vm)
     {
@@ -46,22 +46,23 @@ public function __construct(VirtualMachine $vm)
         $this->vCenter = VCenter::load($vm->get('vcenter_uuid'), $vm->getConnection());
     }
 
-    protected function getDb()
+    protected function getDb(): ?DbConnection
     {
         return $this->vm->getConnection();
     }
 
     /**
-     * @param $annotation
-     * @return string|\ipl\Html\HtmlElement
+     * @param string $annotation
+     *
+     * @return string|HtmlElement
      */
-    protected function formatAnnotation($annotation)
+    protected function formatAnnotation(string $annotation): HtmlElement|string
     {
         $tools = [
             new IbmSpectrumProtect(),
             new NetBackup(),
             new VeeamBackup(),
-            new VRangerBackup(),
+            new VRangerBackup()
         ];
         foreach ($tools as $tool) {
             if ($tool instanceof SimpleBackupTool) {
@@ -71,26 +72,19 @@ protected function formatAnnotation($annotation)
 
         $annotation = trim($annotation);
 
-        if (strpos($annotation, "\n") === false) {
+        if (! str_contains($annotation, "\n")) {
             return $annotation;
-        } else {
-            return Html::tag('pre', null, $annotation);
         }
+
+        return Html::tag('pre', null, $annotation);
     }
 
-    /**
-     * @throws \Icinga\Exception\NotFoundError
-     */
-    protected function assemble()
+    protected function assemble(): void
     {
         $vm = $this->vm;
-        $uuid = $vm->get('uuid');
         $this->addNameValueRow($this->translate('Tools'), $this->prepareTools($vm));
         if ($annotation = $vm->get('annotation')) {
-            $this->addNameValueRow(
-                $this->translate('Annotation'),
-                $this->formatAnnotation($annotation)
-            );
+            $this->addNameValueRow($this->translate('Annotation'), $this->formatAnnotation($annotation));
         }
 
         if ($guestName = $vm->get('guest_full_name')) {
@@ -119,8 +113,8 @@ protected function assemble()
             $this->translate('Guest Hostname') => $vm->get('guest_host_name') ?: '-',
             $this->translate('Guest IP') => $vm->get('guest_ip_address') ?: '-',
             $this->translate('Guest OS') => $guest,
-            $this->translate('Guest Utilities') => $guestInfo,
-            // $this->translate('Test') => $this->getMonitoringInfo($vm),
+            $this->translate('Guest Utilities') => $guestInfo
+            // $this->translate('Test') => $this->getMonitoringInfo($vm)
         ]);
         $quickStats = VmQuickStats::loadFor($vm);
         if ($vm->get('runtime_power_state') === 'poweredOn') {
@@ -131,8 +125,8 @@ protected function assemble()
                     DateFormatter::formatDuration($uptime),
                     $uptime < 900 ? Icon::create('warning-empty', [
                         'class' => ['state', 'yellow'],
-                        'title' => $this->translate('System booted recently'),
-                    ]) : null,
+                        'title' => $this->translate('System booted recently')
+                    ]) : null
                 ]
             );
         }
@@ -147,13 +141,13 @@ protected function assemble()
                 Link::create(
                     $this->translate('VMotion attempt(s)'),
                     'vspheredb/vm/events',
-                    Util::uuidParams($uuid)
+                    Util::uuidParams($vm->get('uuid'))
                 )
             )
         );
     }
 
-    protected function prepareTools(VirtualMachine $vm)
+    protected function prepareTools(VirtualMachine $vm): Hint|array
     {
         $tools = [];
 
@@ -163,7 +157,7 @@ protected function prepareTools(VirtualMachine $vm)
         }
         $tools[] = new VmrcLink($this->vCenter, $vm, 'VMRC');
         $tools[] = ' ';
-        if (\version_compare($this->vCenter->get('api_version'), '6.5', '>=')) {
+        if (version_compare($this->vCenter->get('api_version'), '6.5', '>=')) {
             $tools[] = new Html5UiLink($this->vCenter, $vm, 'HTML5 UI');
             $tools[] = ' ';
         }
@@ -172,7 +166,7 @@ protected function prepareTools(VirtualMachine $vm)
         return $tools;
     }
 
-    protected function getGuestToolsVersionInfo($vm)
+    protected function getGuestToolsVersionInfo(VirtualMachine $vm): string|array
     {
         $info = $vm->get('guest_tools_version');
         if ($info === null) {
@@ -190,8 +184,7 @@ protected function getGuestToolsVersionInfo($vm)
                 )
             )];
         } else {
-            $renderer = new GuestToolsVersionRenderer();
-            $info = $renderer($info);
+            $info = (new GuestToolsVersionRenderer())($info);
         }
 
         return $info;
@@ -199,9 +192,10 @@ protected function getGuestToolsVersionInfo($vm)
 
     /**
      * @param VirtualMachine $vm
-     * @return array|null
+     *
+     * @return array
      */
-    protected function getMonitoringInfo(VirtualMachine $vm)
+    protected function getMonitoringInfo(VirtualMachine $vm): array
     {
         $name = $vm->get('guest_host_name');
         $statusRenderer = new IcingaHostStatusRenderer();
@@ -222,11 +216,9 @@ protected function getMonitoringInfo(VirtualMachine $vm)
                         ['class' => 'icon-right-small']
                     )
                 ];
-            } else {
-                return [Html::sprintf(
-                    "There is no monitored Host mapped to this VM"
-                )];
             }
+
+            return [Html::sprintf("There is no monitored Host mapped to this VM")];
         } catch (Exception $e) {
             return [
                 Hint::error(
diff --git a/library/Vspheredb/Web/Table/Object/VmExtraInfoTable.php b/library/Vspheredb/Web/Table/Object/VmExtraInfoTable.php
index 5ff0d234..079a7a3d 100644
--- a/library/Vspheredb/Web/Table/Object/VmExtraInfoTable.php
+++ b/library/Vspheredb/Web/Table/Object/VmExtraInfoTable.php
@@ -3,6 +3,7 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Object;
 
 use gipfl\Web\Table\NameValueTable;
+use Icinga\Module\Vspheredb\Db\DbConnection;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
@@ -13,11 +14,9 @@ class VmExtraInfoTable extends NameValueTable
 {
     use Translation;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     public function __construct(VirtualMachine $vm)
     {
@@ -26,23 +25,18 @@ public function __construct(VirtualMachine $vm)
         $this->vCenter = VCenter::load($vm->get('vcenter_uuid'), $vm->getConnection());
     }
 
-    protected function getDb()
+    protected function getDb(): ?DbConnection
     {
         return $this->vm->getConnection();
     }
 
-    /**
-     * @throws \Icinga\Exception\NotFoundError
-     */
-    protected function assemble()
+    protected function assemble(): void
     {
-        $vm = $this->vm;
-
         $this->addNameValuePairs([
-            $this->translate('UUID') => Html::tag('pre', $vm->get('bios_uuid')),
-            $this->translate('Instance UUID') => Html::tag('pre', $vm->get('instance_uuid')),
-            $this->translate('CPUs')   => $vm->get('hardware_numcpu'),
-            $this->translate('Version') => $vm->get('version'),
+            $this->translate('UUID') => Html::tag('pre', $this->vm->get('bios_uuid')),
+            $this->translate('Instance UUID') => Html::tag('pre', $this->vm->get('instance_uuid')),
+            $this->translate('CPUs') => $this->vm->get('hardware_numcpu'),
+            $this->translate('Version') => $this->vm->get('version')
         ]);
     }
 }
diff --git a/library/Vspheredb/Web/Table/Object/VmLiveCountersTable.php b/library/Vspheredb/Web/Table/Object/VmLiveCountersTable.php
deleted file mode 100644
index dde454cc..00000000
--- a/library/Vspheredb/Web/Table/Object/VmLiveCountersTable.php
+++ /dev/null
@@ -1,163 +0,0 @@
-<?php
-
-namespace Icinga\Module\Vspheredb\Web\Table\Object;
-
-use DateTime;
-use Exception;
-use gipfl\Web\Table\NameValueTable;
-use Icinga\Application\Benchmark;
-use Icinga\Module\Vspheredb\Api;
-use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
-use Icinga\Module\Vspheredb\Web\Widget\CompactInOutSparkline;
-use ipl\Html\Html;
-use ipl\I18n\Translation;
-
-class VmLiveCountersTable extends NameValueTable
-{
-    use Translation;
-
-    /** @var VirtualMachine */
-    protected $vm;
-
-    /** @var Api */
-    protected $api;
-
-    public function __construct(VirtualMachine $vm, Api $api)
-    {
-        $this->vm = $vm;
-        $this->api = $api;
-    }
-
-    protected function getDb()
-    {
-        return $this->vm->getConnection();
-    }
-
-    protected function assemble()
-    {
-        $this->addLiveCounters();
-    }
-
-    protected function addLiveCounters()
-    {
-        $vm = $this->vm;
-        $uuid = $vm->get('uuid');
-
-        $info = [
-            526 => 'Data receive rate',
-            527 => 'Data transmit rate',
-            543 => 'Read Latency',
-            544 => 'Write Latency',
-            171 => 'Average Read/s',
-            172 => 'Average Write/s',
-        ];
-
-        $units = [
-            526 => 'kByte/s',
-            527 => 'kByte/s',
-            543 => 'µs',
-            544 => 'µs',
-            171 => 'average reads/s',
-            172 => 'average writes/s',
-        ];
-
-        try {
-            $interval = 20;
-            $someData = $this->fetchSomePerfdata($interval);
-            $someData = $someData[0];
-            Benchmark::measure('Got data from vCenter');
-            $times = array_values(
-                array_filter(
-                    preg_split('/,/', $someData->sampleInfoCSV),
-                    function ($val) use ($interval) {
-                        return $val !== (string) $interval;
-                    }
-                )
-            );
-
-            $first = new DateTime(array_shift($times));
-            $last = new DateTime(array_pop($times));
-            $first = (int) $first->format('U') * 1000;
-            $last = (int) $last->format('U') * 1000;
-            foreach ($someData->value as $data) {
-                $this->addNameValueRow(
-                    sprintf(
-                        '%s (%s)',
-                        $data->id->instance,
-                        $info[$data->id->counterId ?? '']
-                    ),
-                    [
-                        Html::tag('span', [
-                            'class'      => 'sparkline overspark',
-                            'sparkType'  => 'line',
-                            'data-first' => $first,
-                            'data-last'  => $last,
-                            'data-interval' => $interval,
-                            'values' => $data->value
-                        ]),
-                        Html::tag('span', [
-                            'class' => 'sparkinfo'
-                        ]),
-                        Html::tag('span', null, ' ' . $units[$data->id->counterId ?? ''])
-                    ]
-                );
-            }
-        } catch (Exception $e) {
-            $this->addNameValueRow('ERROR', $e->getMessage());
-        }
-        foreach ($this->fetchPerf($uuid) as $instance => $perf) {
-            $this->addNameValueRow($instance, $perf);
-        }
-    }
-
-    protected function fetchPerf($uuid)
-    {
-        $db = $this->getDb()->getDbAdapter();
-
-        $values = implode(" || ',' || ", [
-            'value_minus4',
-            'value_minus3',
-            'value_minus2',
-            'value_minus1',
-            'value_last',
-        ]);
-
-        $query = $db->select()->from('counter_300x5', [
-            'instance',
-            'counter_key',
-            'value' => $values,
-        ])->where('object_uuid = ?', $uuid)
-            ->where('counter_key IN (?)', [171, 172, 526, 527])
-            ->order('counter_key')->order('instance');
-
-        $rows = $db->fetchAll($query);
-
-        $result = [];
-        /** @var object{instance: string, counter_key: int, value: string} $row */
-        foreach ($rows as $row) {
-            $result[$row->instance][$row->counter_key] = $row->value;
-        }
-
-        $final = [];
-
-        foreach ($result as $instance => $entries) {
-            $in = array_shift($entries);
-            $out = array_shift($entries);
-            $final[$instance] = new CompactInOutSparkline($in, $out);
-        }
-
-        return $final;
-    }
-
-    protected function fetchSomePerfdata($interval)
-    {
-        $raw = $this->api->perfManager()->oldTestQueryPerf(
-            $this->vm->object()->get('moref'),
-            'VirtualMachine',
-            $interval,
-            600
-        );
-
-        return $raw->returnval;
-    }
-}
diff --git a/library/Vspheredb/Web/Table/Object/VmLocationInfoTable.php b/library/Vspheredb/Web/Table/Object/VmLocationInfoTable.php
index fbe11393..9ec0ef88 100644
--- a/library/Vspheredb/Web/Table/Object/VmLocationInfoTable.php
+++ b/library/Vspheredb/Web/Table/Object/VmLocationInfoTable.php
@@ -5,6 +5,8 @@
 use gipfl\Web\Table\NameValueTable;
 use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
+use Icinga\Module\Vspheredb\Db;
+use Icinga\Module\Vspheredb\Db\DbConnection;
 use Icinga\Module\Vspheredb\DbObject\HostQuickStats;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
@@ -18,17 +20,16 @@
 use Icinga\Module\Vspheredb\Web\Widget\Renderer\PathToObjectRenderer;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\I18n\Translation;
 
 class VmLocationInfoTable extends NameValueTable
 {
     use Translation;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     public function __construct(VirtualMachine $vm, VCenter $vCenter)
     {
@@ -37,15 +38,15 @@ public function __construct(VirtualMachine $vm, VCenter $vCenter)
         $this->vCenter = $vCenter;
     }
 
-    protected function getDb()
+    protected function getDb(): ?DbConnection
     {
         return $this->vm->getConnection();
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $vm = $this->vm;
-        /** @var \Icinga\Module\Vspheredb\Db $connection */
+        /** @var Db $connection */
         $connection = $vm->getConnection();
         $lookup =  new PathLookup($connection->getDbAdapter());
         $hostUuid = $vm->get('runtime_host_uuid');
@@ -60,14 +61,12 @@ protected function assemble()
                 $hostInfo = [
                     $lookup->linkToObject($hostUuid),
                     Html::tag('br'),
-                    ConnectionStateDetails::getFor($vm->get('connection_state')),
+                    ConnectionStateDetails::getFor($vm->get('connection_state'))
                 ];
                 $hostResources = $this->prepareHostInfo($host, $quickStats);
-            } catch (NotFoundError $e) {
+            } catch (NotFoundError) {
                 $hostResources = '-';
-                $hostInfo = Html::tag('span', [
-                    'class' => 'error'
-                ], $this->translate('Failed to load related host'));
+                $hostInfo = Html::tag('span', ['class' => 'error'], $this->translate('Failed to load related host'));
             }
         }
 
@@ -77,31 +76,29 @@ protected function assemble()
             $this->translate('Host Resources') => $hostResources,
             $this->translate('Resource Pool') => $lookup->linkToObject($vm->get('resource_pool_uuid')),
             $this->translate('Path') => PathToObjectRenderer::render($vm),
-            $this->translate('vCenter') => new VCenterLink($this->vCenter),
+            $this->translate('vCenter') => new VCenterLink($this->vCenter)
         ]);
     }
 
-    protected function prepareHostInfo(HostSystem $host, HostQuickStats $quickStats)
+    protected function prepareHostInfo(HostSystem $host, HostQuickStats $quickStats): HtmlElement
     {
         $cpuCapacity = $host->get('hardware_cpu_cores') * $host->get('hardware_cpu_mhz');
         $cpuUsed = $quickStats->get('overall_cpu_usage');
         $memCapacity = $host->get('hardware_memory_size_mb');
         $memUsed = $quickStats->get('overall_memory_usage_mb');
 
-        return Html::tag('div', [
-            'class' => 'resource-info-small'
-        ], Html::tag('div', [
+        return Html::tag('div', ['class' => 'resource-info-small'], Html::tag('div', [
             new CpuUsage($cpuUsed, $cpuCapacity),
-            \sprintf(
+            sprintf(
                 $this->translate('Free CPU: %s'),
                 Format::mhz($cpuCapacity - $cpuUsed)
             ),
             Html::tag('br'),
             new MemoryUsage($memUsed, $memCapacity),
-            \sprintf(
+            sprintf(
                 $this->translate('Free Memory: %s'),
                 Format::mBytes($memCapacity - $memUsed)
-            ),
+            )
         ]));
     }
 }
diff --git a/library/Vspheredb/Web/Table/Object/known-vendor-model-images.php b/library/Vspheredb/Web/Table/Object/known-vendor-model-images.php
index 56d900bf..882b09bf 100644
--- a/library/Vspheredb/Web/Table/Object/known-vendor-model-images.php
+++ b/library/Vspheredb/Web/Table/Object/known-vendor-model-images.php
@@ -15,7 +15,7 @@
         'UCSC-C480-M5' => 'https://www.cisco.com/c/dam/en/us/products/collateral/servers-unified-computing/'
             . 'ucs-c-series-rack-servers/datasheet-c78-739291.docx/_jcr_content/renditions/datasheet-c78-739291_0.png',
         'UCSC-C240-M6S' => 'https://www.cisco.com/content/dam/en/us/products/collateral/servers-unified-computing/'
-            . 'ucs-c-series-rack-servers/images/cisco-ucs-c240-m6-rack-server.png',
+            . 'ucs-c-series-rack-servers/images/cisco-ucs-c240-m6-rack-server.png'
     ],
     'Dell Inc.' => [
         'PowerEdge R610' => 'https://i.dell.com/is/image/DellContent/content/dam/'
@@ -57,7 +57,7 @@
             . 'c6525/global_spi/ng/enterprise-server-poweredge-r7515-lf-bestof-500-ng.psd?fmt=png-alpha',
         'PowerEdge R7525' => 'https://i.dell.com/is/image/DellContent/content/dam/'
             . 'global-site-design/product_images/dell_enterprise_products/enterprise_systems/poweredge/'
-            . 'poweredge_r7525/global_spi/ng/enterprise-servers-poweredge-r7525-lf-bestof-500-ng.psd?fmt=png-alpha',
+            . 'poweredge_r7525/global_spi/ng/enterprise-servers-poweredge-r7525-lf-bestof-500-ng.psd?fmt=png-alpha'
     ],
     'HPE' => [
         // End of life, found no HPE URL:
@@ -69,19 +69,19 @@
         'ProLiant DL360 Gen10'              => 'https://assets.ext.hpe.com/is/image/hpedam/s00005869?$zoom$#.png',
         'ProLiant DL380 Gen10'              => [
             'url' => 'https://assets.ext.hpe.com/is/image/hpedam/s00009709?$zoom$#.png',
-            'class' => 'vendor-model-hpe-proliant-dl380-gen10',
+            'class' => 'vendor-model-hpe-proliant-dl380-gen10'
         ],
         'ProLiant DL380 Gen10 Plus'         => [
-            'url' => 'https://assets.ext.hpe.com/is/image/hpedam/s00009868?$zoom$#.png',
+            'url' => 'https://assets.ext.hpe.com/is/image/hpedam/s00009868?$zoom$#.png'
         ],
         'ProLiant DL385 Gen10 Plus'         => 'https://assets.ext.hpe.com/is/image/hpedam/s00009923?$zoom$#.png',
         'ProLiant DL560 Gen10'              => [
             'url' => 'https://assets.ext.hpe.com/is/image/hpedam/s00002844?$zoom$#.png',
-            'class' => 'vendor-model-hpe-proliant-dl560-gen10',
+            'class' => 'vendor-model-hpe-proliant-dl560-gen10'
         ],
         'ProLiant DL580 Gen10'              => [
             'url' => 'https://assets.ext.hpe.com/is/image/hpedam/s00005353?$zoom$#.png',
-            'class' => 'vendor-model-hpe-proliant-dl580-gen10',
+            'class' => 'vendor-model-hpe-proliant-dl580-gen10'
         ],
 
         'Synergy 480 Gen10'                 => 'https://assets.ext.hpe.com/is/image/hpedam/s00002866?$zoom$#.png',
@@ -96,7 +96,7 @@
         // 'ProLiant DL580 Gen10'           => 'https://assets.ext.hpe.com/is/image/hpedam/s00001910?$zoom$#.png',
 
         // Variant:
-        // 'ProLiant DL560 Gen10' => 'https://assets.ext.hpe.com/is/image/hpedam/s00004976?$zoom$#.png',
+        // 'ProLiant DL560 Gen10' => 'https://assets.ext.hpe.com/is/image/hpedam/s00004976?$zoom$#.png'
     ],
     'HP' => [
         'ProLiant DL580 Gen9' => 'https://support.hpe.com/hpesc/public/api/document/c04683220/'
@@ -106,7 +106,7 @@
         'ProLiant DL380 Gen9' => [
             'url' => 'https://techlibrary.hpe.com/docs/enterprise/servers/DL380Gen9/'
             . 'DL380Gen9-setup/system_setup_overview/222457.png',
-            'class' => 'vendor-model-hp-proliant-dl380-gen9',
+            'class' => 'vendor-model-hp-proliant-dl380-gen9'
         ],
         'ProLiant BL460c Gen9' => 'https://techlibrary.hpe.com/docs/enterprise/servers/BL460cGen9/'
             . 'BL460cGen9-setup/de/system_setup_overview/189999.png'
@@ -124,7 +124,7 @@
         'ThinkAgile HX7520 Appliance -[7X84CTO6WW]-' => 'https://lenovopress.lenovo.com/assets/images/LP0730/'
             . 'HX7520-overview.png',
         'Lenovo ThinkAgile HX7520 Appliance -[7X84CTO6WW]-' => 'https://lenovopress.lenovo.com/assets/images/LP0730/'
-            . 'HX7520-overview.png',
+            . 'HX7520-overview.png'
     ],
     'FUJITSU' => [
         'PRIMERGY CX2560 M5' => 'https://www.fujitsu.com/de/imagesgig5/W-DK43300_tcm20-4285182_tcm20-5309118-32.png',
@@ -132,7 +132,7 @@
             . '.png',
         'PRIMERGY RX2540 M2' => 'https://www.fujitsu.com/de/Images/W-DK42852_tcm20-3057159.png',
         'PRIMERGY RX2540 M3' => 'https://www.fujitsu.com/de/Images/W-DK42852_tcm20-3057159.png',
-        'PRIMERGY RX2540 M4' => 'https://www.fujitsu.com/de/Images/W-DK42852_tcm20-3057159.png',
+        'PRIMERGY RX2540 M4' => 'https://www.fujitsu.com/de/Images/W-DK42852_tcm20-3057159.png'
     ],
     'IBM' => [
         '/^(?:System )?x3850 X6/' => 'https://lenovopress.com/assets/images/tips1084/0.212C.jpg',
@@ -146,6 +146,6 @@
     ],
     'Nutanix' => [
         'NX-3170-G8' => 'https://download.nutanix.com/documentation/NX-hardware/images/'
-        . 'front-panel-callouts-nx3170g8-nx8170g8.png',
-    ],
+        . 'front-panel-callouts-nx3170g8-nx8170g8.png'
+    ]
 ];
diff --git a/library/Vspheredb/Web/Table/Objects/ComputeClusterHostSummaryTable.php b/library/Vspheredb/Web/Table/Objects/ComputeClusterHostSummaryTable.php
index 1435f91b..ab45be96 100644
--- a/library/Vspheredb/Web/Table/Objects/ComputeClusterHostSummaryTable.php
+++ b/library/Vspheredb/Web/Table/Objects/ComputeClusterHostSummaryTable.php
@@ -6,20 +6,20 @@
 
 class ComputeClusterHostSummaryTable extends HostSummaryTable
 {
-    protected $baseUrl = 'vspheredb/compute-cluster';
+    protected ?string $baseUrl = 'vspheredb/compute-cluster';
 
-    protected $baseUrlHosts = 'vspheredb/compute-cluster/hosts';
+    protected string $baseUrlHosts = 'vspheredb/compute-cluster/hosts';
 
-    protected $groupBy = 'o.uuid';
+    protected ?string $groupBy = 'o.uuid';
 
-    protected $nameColumn = 'o.object_name';
+    protected ?string $nameColumn = 'o.object_name';
 
-    protected function getGroupingTitle()
+    protected function getGroupingTitle(): string
     {
         return $this->translate('Compute Cluster');
     }
 
-    protected function getFilterParams($row)
+    protected function getFilterParams(object $row): array
     {
         return Util::uuidParams($row->uuid);
     }
diff --git a/library/Vspheredb/Web/Table/Objects/DatacentersTable.php b/library/Vspheredb/Web/Table/Objects/DatacentersTable.php
index f9ae94b2..c286371d 100644
--- a/library/Vspheredb/Web/Table/Objects/DatacentersTable.php
+++ b/library/Vspheredb/Web/Table/Objects/DatacentersTable.php
@@ -2,11 +2,14 @@
 
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
+use gipfl\ZfDb\Select;
+use Zend_Db_Select;
+
 class DatacentersTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/vms?showDescendants';
+    protected ?string $baseUrl = 'vspheredb/vms?showDescendants';
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createOverallStatusColumn(),
@@ -14,21 +17,18 @@ protected function initialize()
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'overall_status',
-            'object_name',
+            'object_name'
         ];
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $this->getRequiredDbColumns()
-        )->where('object_type = ?', 'Datacenter');
-
-        return $query;
+        return $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->where('object_type = ?', 'Datacenter');
     }
 }
diff --git a/library/Vspheredb/Web/Table/Objects/DatastoreTable.php b/library/Vspheredb/Web/Table/Objects/DatastoreTable.php
index b9a28d96..cd587177 100644
--- a/library/Vspheredb/Web/Table/Objects/DatastoreTable.php
+++ b/library/Vspheredb/Web/Table/Objects/DatastoreTable.php
@@ -3,131 +3,116 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
 use gipfl\IcingaWeb2\Link;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\DbObject\Datastore;
 use Icinga\Module\Vspheredb\Web\Widget\DatastoreUsage;
 use Icinga\Util\Format;
+use ipl\Html\Attributes;
 use Ramsey\Uuid\Uuid;
+use Zend_Db_Select;
 
-class DatastoreTable extends ObjectsTable
+class DatastoreTable extends PercentObjectsTable
 {
-    protected function initialize()
+    protected function initialize(): void
     {
-        $this->addAttributes(['class' => 'datastores-table']);
+        $this->addAttributes(Attributes::create(['class' => 'datastores-table']));
         $this->addAvailableColumns([
             $this->createOverallStatusColumn(),
+
             $this->createColumn('object_name', $this->translate('Name'), [
-                'overall_status'       => 'o.overall_status',
-                'object_name'          => 'o.object_name',
-                'uuid'                 => 'o.uuid',
-                'capacity'             => 'ds.capacity',
-                'free_space'           => 'ds.free_space',
-                'uncommitted'          => 'ds.uncommitted',
-                'free_space_percent'   => '(ds.free_space / ds.capacity) * 100',
-                'uncommitted_percent'  => '(ds.uncommitted / ds.capacity) * 100',
-            ])->setRenderer(function ($row) {
-                $row->object_name = Anonymizer::anonymizeString($row->object_name);
-                if (in_array('overall_status', $this->getChosenColumnNames())) {
-                    $result = [];
-                } else {
-                    $statusRenderer = $this->overallStatusRenderer();
-                    $result = [$statusRenderer($row)];
-                }
-                $title = sprintf(
+                'overall_status'      => 'o.overall_status',
+                'object_name'         => 'o.object_name',
+                'uuid'                => 'o.uuid',
+                'capacity'            => 'ds.capacity',
+                'free_space'          => 'ds.free_space',
+                'uncommitted'         => 'ds.uncommitted',
+                'free_space_percent'  => '(ds.free_space / ds.capacity) * 100',
+                'uncommitted_percent' => '(ds.uncommitted / ds.capacity) * 100'
+            ])
+                ->setRenderer(function ($row) {
+                    $row->object_name = Anonymizer::anonymizeString($row->object_name);
+                    if (in_array('overall_status', $this->getChosenColumnNames())) {
+                        $result = [];
+                    } else {
+                        $statusRenderer = $this->overallStatusRenderer();
+                        $result = [$statusRenderer($row)];
+                    }
+                    $title = sprintf(
                     // '%d VM(s), %s of %s used, %s uncommitted',
-                    '%s of %s used, %s uncommitted',
-                    // $row->cnt_vm,
-                    $this->formatBytesPercent($row, 'free_space'),
-                    Format::bytes($row->capacity, Format::STANDARD_IEC),
-                    $this->formatBytesPercent($row, 'uncommitted')
-                );
-
-                $result[] = Link::create(
-                    $row->object_name,
-                    'vspheredb/datastore',
-                    ['uuid' => Uuid::fromBytes($row->uuid)->toString()],
-                    ['title' => $title]
-                );
-
-                return $result;
-            }),
+                        '%s of %s used, %s uncommitted',
+                        // $row->cnt_vm,
+                        $this->formatBytesPercent($row, 'free_space'),
+                        Format::bytes($row->capacity, Format::STANDARD_IEC),
+                        $this->formatBytesPercent($row, 'uncommitted')
+                    );
+
+                    $result[] = Link::create(
+                        $row->object_name,
+                        'vspheredb/datastore',
+                        ['uuid' => Uuid::fromBytes($row->uuid)->toString()],
+                        ['title' => $title]
+                    );
+
+                    return $result;
+                }),
+
             $this->createColumn('vcenter_name', $this->translate('vCenter / ESXi'), 'vc.name'),
-            $this->createColumn(
-                'multiple_host_access',
-                $this->translate('Multiple Hosts'),
-                'ds.multiple_host_access'
-            )->setRenderer(function ($row) {
-                return $row->multiple_host_access === 'y' ? $this->translate('Yes') : $this->translate('No');
-            }),
+
+            $this->createColumn('multiple_host_access', $this->translate('Multiple Hosts'), 'ds.multiple_host_access')
+                ->setRenderer(
+                    fn($row) => $row->multiple_host_access === 'y' ? $this->translate('Yes') : $this->translate('No')
+                ),
+
             $this->createColumn('free_space', $this->translate('Free'), 'ds.free_space')
-                ->setRenderer(function ($row) {
-                    return Format::bytes($row->free_space, Format::STANDARD_IEC);
-                }),
+                ->setRenderer(fn($row) => Format::bytes($row->free_space, Format::STANDARD_IEC)),
+
             $this->createColumn('free_space_percent', $this->translate('Free (%)'), [
-                'free_space_percent'  => '(ds.free_space / ds.capacity) * 100'
-            ])->setRenderer(function ($row) {
-                return $this->formatPercent($row->free_space_percent);
-            }),
+                'free_space_percent' => '(ds.free_space / ds.capacity) * 100'
+            ])
+                ->setRenderer(fn($row) => $this->formatPercent($row->free_space_percent)),
+
             $this->createColumn('uncommitted', $this->translate('Uncommitted'), 'ds.uncommitted')
-                ->setRenderer(function ($row) {
-                    return Format::bytes($row->uncommitted, Format::STANDARD_IEC);
-                }),
+                ->setRenderer(fn($row) => Format::bytes($row->uncommitted, Format::STANDARD_IEC)),
+
             $this->createColumn('uncommitted_percent', $this->translate('Uncommitted (%)'), [
-                'uncommitted_percent'  => '(ds.uncommitted / ds.capacity) * 100'
-            ])->setRenderer(function ($row) {
-                return $this->formatPercent($row->uncommitted_percent);
-            }),
+                'uncommitted_percent' => '(ds.uncommitted / ds.capacity) * 100'
+            ])
+                ->setRenderer(fn($row) => $this->formatPercent($row->uncommitted_percent)),
+
             $this->createColumn('size', $this->translate('Size'), 'ds.capacity')
+                ->setRenderer(fn($row) => Format::bytes($row->capacity, Format::STANDARD_IEC)),
+
+            $this->createColumn('cnt_vms', $this->translate('VMs'), ['cnt_vms' => 'COALESCE(vdu.cnt_vms, 0)'])
+                ->setDefaultSortDirection('DESC'),
+
+            $this->createColumn('usage', $this->translate('Usage'), ['uuid' => 'o.uuid'])
                 ->setRenderer(function ($row) {
-                    return Format::bytes($row->capacity, Format::STANDARD_IEC);
-                }),
-            $this->createColumn('cnt_vms', $this->translate('VMs'), [
-                'cnt_vms' => 'COALESCE(vdu.cnt_vms, 0)',
-            ])->setDefaultSortDirection('DESC'),
-            $this->createColumn('usage', $this->translate('Usage'), [
-                'uuid' => 'o.uuid'
-            ])->setRenderer(function ($row) {
-                /** @var Db $connection */
-                $connection = $this->connection();
-                $usage = new DatastoreUsage(Datastore::load($row->uuid, $connection));
-                $usage->getAttributes()->add('class', 'compact');
-                $usage->loadAllVmDisks()->addFreeDatastoreSpace();
-
-                return $usage;
-            })->setSortExpression(
-                '1 - (ds.free_space / ds.capacity)'
-            )->setDefaultSortDirection('DESC'),
+                    /** @var Db $connection */
+                    $connection = $this->connection();
+                    $usage = new DatastoreUsage(Datastore::load($row->uuid, $connection));
+                    $usage->getAttributes()->add('class', 'compact');
+                    $usage->loadAllVmDisks()->addFreeDatastoreSpace();
+
+                    return $usage;
+                })
+                ->setSortExpression('1 - (ds.free_space / ds.capacity)')
+                ->setDefaultSortDirection('DESC')
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'object_name',
             'free_space',
             'size',
-            'usage',
+            'usage'
         ];
     }
 
-    protected function formatBytesPercent($row, $name)
-    {
-        $bytes = $row->$name;
-        $percent = $row->{"{$name}_percent"};
-        return sprintf(
-            '%s (%s)',
-            Format::bytes($bytes, Format::STANDARD_IEC),
-            $this->formatPercent($percent)
-        );
-    }
-
-    protected function formatPercent($value)
-    {
-        return sprintf('%0.2f%%', $value);
-    }
-
-    public function sortBy($columns)
+    public function sortBy(array|string $columns): static
     {
         parent::sortBy($columns);
 
@@ -136,7 +121,7 @@ public function sortBy($columns)
         return $this;
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
         $wantsVCenter = false;
         $columns = $this->getRequiredDbColumns();
@@ -146,34 +131,19 @@ public function prepareQuery()
             ->group('o.uuid');
 
         foreach ($columns as $column) {
-            if (substr($column, 0, 3) === 'vc.') {
+            if (str_starts_with($column, 'vc.')) {
                 $wantsVCenter = true;
             }
         }
 
         if ($this->hasColumn('cnt_vms')) {
-            $vduQuery = $this->db()->select()->from('vm_datastore_usage', [
-                'cnt_vms' => 'COUNT(*)',
-                'ds_uuid' => 'datastore_uuid',
-            ])->group('datastore_uuid');
-            $query->joinLeft(
-                ['vdu' => $vduQuery],
-                'vdu.ds_uuid = o.uuid',
-                []
-            );
+            $vduQuery = $this->db()->select()
+                ->from('vm_datastore_usage', ['cnt_vms' => 'COUNT(*)', 'ds_uuid' => 'datastore_uuid'])
+                ->group('datastore_uuid');
+            $query->joinLeft(['vdu' => $vduQuery], 'vdu.ds_uuid = o.uuid', []);
         }
         if ($wantsVCenter) {
-            $query->join(
-                ['vc' => 'vcenter'],
-                'vc.instance_uuid = ds.vcenter_uuid',
-                []
-            );
-        }
-        if ($this->parentUuids) {
-            $query->where('o.parent_uuid IN (?)', $this->parentUuids);
-        }
-        if ($this->filterVCenter) {
-            $query->where('o.vcenter_uuid = ?', $this->filterVCenter->getUuid());
+            $query->join(['vc' => 'vcenter'], 'vc.instance_uuid = ds.vcenter_uuid', []);
         }
 
         return $query;
diff --git a/library/Vspheredb/Web/Table/Objects/GroupedvmsTable.php b/library/Vspheredb/Web/Table/Objects/GroupedvmsTable.php
index e8b2c524..c2bd4688 100644
--- a/library/Vspheredb/Web/Table/Objects/GroupedvmsTable.php
+++ b/library/Vspheredb/Web/Table/Objects/GroupedvmsTable.php
@@ -3,62 +3,40 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
 use gipfl\IcingaWeb2\Link;
+use gipfl\ZfDb\Select;
+use Icinga\Module\Vspheredb\Format;
 use Icinga\Module\Vspheredb\Util;
+use Icinga\Module\Vspheredb\Web\Table\SimpleColumn;
 use Icinga\Module\Vspheredb\Web\Widget\MemoryUsage;
-use Icinga\Module\Vspheredb\Format;
+use Zend_Db_Select;
 
 class GroupedvmsTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/vm';
+    protected ?string $baseUrl = 'vspheredb/vm';
 
-    protected $groupByAlias = 'project';
+    protected string $groupByAlias = 'project';
 
-    protected $groupBy = '(SUBSTR(o.object_name, 1, POSITION(\'-\' IN o.object_name) - 1))';
+    protected string $groupBy = '(SUBSTR(o.object_name, 1, POSITION(\'-\' IN o.object_name) - 1))';
 
-    public function filter($uuid)
+    public function filter(string $uuid): static
     {
         $this->getQuery()->where('vm.runtime_host_uuid = ?', $uuid);
 
         return $this;
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $this->getRequiredDbColumns()
-        )->join(
-            ['vm' => 'virtual_machine'],
-            'o.uuid = vm.uuid',
-            []
-        )->group($this->groupByAlias);
-
-        $query->join(
-            ['h' => 'host_system'],
-            'vm.runtime_host_uuid = h.uuid',
-            []
-        )->join(
-            ['ho' => 'object'],
-            'ho.uuid = h.uuid',
-            []
-        );
-        $query->join(
-            ['vqs' => 'vm_quick_stats'],
-            'vqs.uuid = vm.uuid',
-            []
-        );
-
-        if ($this->parentUuids) {
-            $query->where('ho.parent_uuid IN (?)', $this->parentUuids);
-        }
-        if ($this->filterVCenter) {
-            $query->where('ho.vcenter_uuid = ?', $this->filterVCenter->getUuid());
-        }
-
-        return $query;
+        return $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->join(['vm' => 'virtual_machine'], 'o.uuid = vm.uuid', [])
+            ->group($this->groupByAlias)
+            ->join(['h' => 'host_system'], 'vm.runtime_host_uuid = h.uuid', [])
+            ->join(['ho' => 'object'], 'ho.uuid = h.uuid', [])
+            ->join(['vqs' => 'vm_quick_stats'], 'vqs.uuid = vm.uuid', []);
     }
 
-    protected function createGroupingColumn()
+    protected function createGroupingColumn(): SimpleColumn
     {
         return $this->createColumn($this->groupByAlias, 'Project', $this->groupBy)
             ->setRenderer(function ($row) {
@@ -76,49 +54,48 @@ protected function createGroupingColumn()
             });
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createGroupingColumn(),
             /*
             $this->createColumn('cpu', 'CPU', [
                 'used_mhz'  => 'SUM(vqs.overall_cpu_usage)',
-                'total_mhz' => 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)',
+                'total_mhz' => 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)'
             ])->setRenderer(function ($row) {
                 return new CpuUsage($row->used_mhz, $row->total_mhz);
             })->setSortExpression(
                 'SUM(hqs.overall_cpu_usage) / SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)'
             )->setDefaultSortDirection('DESC'),
             */
+
             $this->createColumn('hardware_numcpu', $this->translate('vCPU Count'), 'SUM(vm.hardware_numcpu)')
                 ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('cpu_usage', 'CPU', 'SUM(vqs.overall_cpu_usage)')
-                ->setRenderer(function ($row) {
-                    return Format::mhz($row->cpu_usage);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::mhz($row->cpu_usage))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('memory', $this->translate('Memory'), [
                 'used_mb'      => 'SUM(vqs.guest_memory_usage_mb)',
                 'total_mb'     => 'SUM(vm.hardware_memorymb)',
-                'host_used_mb' => 'SUM(vqs.host_memory_usage_mb)',
-            ])->setRenderer(function ($row) {
-                return new MemoryUsage($row->used_mb, $row->total_mb, $row->host_used_mb);
-            })->setSortExpression(
-                'SUM(vqs.guest_memory_usage_mb) / SUM(vm.hardware_memorymb)'
-            )->setDefaultSortDirection('DESC'),
+                'host_used_mb' => 'SUM(vqs.host_memory_usage_mb)'
+            ])
+                ->setRenderer(fn($row) => new MemoryUsage($row->used_mb, $row->total_mb, $row->host_used_mb))
+                ->setSortExpression('SUM(vqs.guest_memory_usage_mb) / SUM(vm.hardware_memorymb)')
+                ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('host_memory', $this->translate('Host Memory'), [
-                'host_used_mb'  => 'SUM(vqs.host_memory_usage_mb)',
-                'total_mb' => 'SUM(vm.hardware_memorymb)',
-            ])->setRenderer(function ($row) {
-                return new MemoryUsage($row->host_used_mb, $row->total_mb);
-            })->setSortExpression(
-                'AVG(vqs.host_memory_usage_mb / vm.hardware_memorymb)'
-            )->setDefaultSortDirection('DESC'),
-
+                'host_used_mb' => 'SUM(vqs.host_memory_usage_mb)',
+                'total_mb'     => 'SUM(vm.hardware_memorymb)'
+            ])
+                ->setRenderer(fn($row) => new MemoryUsage($row->host_used_mb, $row->total_mb))
+                ->setSortExpression('AVG(vqs.host_memory_usage_mb / vm.hardware_memorymb)')
+                ->setDefaultSortDirection('DESC'),
             /*
             $this->createColumn('memory', 'Host Memory', [
                 'used_mb'  => 'SUM(vqs.host_memory_usage_mb)',
-                'total_mb' => 'SUM(vm.hardware_memorymb)',
+                'total_mb' => 'SUM(vm.hardware_memorymb)'
             ])->setRenderer(function ($row) {
                 $used = $row->used_mb * 1024 * 1024;
                 $total = $row->total_mb * 1024 * 1024;
@@ -131,24 +108,23 @@ protected function initialize()
                 return [
                     new SimpleUsageBar($used, $total, $title),
                     Html::tag('small', ['style' => 'float: left'], 'Used: ' . Format::bytes($used)),
-                    Html::tag('small', ['style' => 'float: right'], 'Capacity: ' . Format::bytes($total)),
+                    Html::tag('small', ['style' => 'float: right'], 'Capacity: ' . Format::bytes($total))
                 ];
             })->setSortExpression(
                 'AVG(hqs.overall_memory_usage_mb / h.hardware_memory_size_mb)'
             )->setDefaultSortDirection('DESC'),
-*/
+            */
 
             $this->createColumn('vms', 'VMs', 'COUNT(*)')
                 ->setDefaultSortDirection('DESC'),
-            $this->createColumn('hardware_memorymb', 'Memory Capacity', 'SUM(vm.hardware_memorymb)')
-                ->setRenderer(function ($row) {
-                    return Format::mBytes($row->hardware_memorymb);
-                })->setDefaultSortDirection('DESC'),
 
+            $this->createColumn('hardware_memorymb', 'Memory Capacity', 'SUM(vm.hardware_memorymb)')
+                ->setRenderer(fn($row) => Format::mBytes($row->hardware_memorymb))
+                ->setDefaultSortDirection('DESC')
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'project',
diff --git a/library/Vspheredb/Web/Table/Objects/HostSummaryTable.php b/library/Vspheredb/Web/Table/Objects/HostSummaryTable.php
index d2c9f4cc..c33347e5 100644
--- a/library/Vspheredb/Web/Table/Objects/HostSummaryTable.php
+++ b/library/Vspheredb/Web/Table/Objects/HostSummaryTable.php
@@ -3,61 +3,46 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
 use gipfl\IcingaWeb2\Link;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Format;
+use Icinga\Module\Vspheredb\Web\Table\SimpleColumn;
 use Icinga\Module\Vspheredb\Web\Widget\CpuUsage;
 use Icinga\Module\Vspheredb\Web\Widget\MemoryUsage;
 use ipl\Html\Html;
 use Ramsey\Uuid\Uuid;
+use Zend_Db_Select;
 
 abstract class HostSummaryTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/computeresource';
+    protected ?string $baseUrl = 'vspheredb/computeresource';
 
-    protected $baseUrlHosts = 'vspheredb/hosts';
+    protected string $baseUrlHosts = 'vspheredb/hosts';
 
-    protected $searchColumns = [
-        'name',
-    ];
+    protected $searchColumns = ['name'];
 
-    protected $groupByAlias = 'name';
+    protected string $groupByAlias = 'name';
 
-    protected $nameColumn;
+    protected ?string $nameColumn = null;
 
-    protected $groupBy;
+    protected ?string $groupBy = null;
 
-    abstract protected function getFilterParams($row);
+    abstract protected function getFilterParams(object $row): array;
 
-    abstract protected function getGroupingTitle();
+    abstract protected function getGroupingTitle(): string;
 
-    protected function prepareUnGroupedQuery()
+    protected function prepareUnGroupedQuery(): Select|Zend_Db_Select
     {
-        return $this->db()->select()->from(
-            ['o' => 'object'],
-            $this->getRequiredDbColumns()
-        )->join(
-            ['ho' => 'object'],
-            'ho.parent_uuid = o.uuid',
-            []
-        )->join(
-            ['h' => 'host_system'],
-            'ho.uuid = h.uuid',
-            []
-        )->join(
-            ['hqs' => 'host_quick_stats'],
-            'hqs.uuid = h.uuid',
-            []
-        )->where('h.runtime_power_state = ?', 'poweredOn');
+        return $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->join(['ho' => 'object'], 'ho.parent_uuid = o.uuid', [])
+            ->join(['h' => 'host_system'], 'ho.uuid = h.uuid', [])
+            ->join(['hqs' => 'host_quick_stats'], 'hqs.uuid = h.uuid', [])
+            ->where('h.runtime_power_state = ?', 'poweredOn');
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
         $query = $this->prepareUnGroupedQuery();
-        if ($this->parentUuids) {
-            $query->where('o.uuid IN (?)', $this->parentUuids);
-        }
-        if ($this->filterVCenter) {
-            $query->where('o.vcenter_uuid = ?', $this->filterVCenter->getUuid());
-        }
 
         if ($this->groupBy !== null) {
             $query->group($this->groupBy);
@@ -66,11 +51,11 @@ public function prepareQuery()
         return $query;
     }
 
-    protected function createGroupingColumn()
+    protected function createGroupingColumn(): SimpleColumn
     {
         return $this->createColumn($this->groupByAlias, $this->getGroupingTitle(), [
             'name'         => $this->nameColumn,
-            'uuid'         => $this->groupBy,
+            'uuid'         => $this->groupBy
         ] + $this->getHostCountColumns())->setRenderer(function ($row) {
             $link = Link::create(
                 $row->{$this->groupByAlias},
@@ -82,106 +67,109 @@ protected function createGroupingColumn()
             return [
                 $this->getExtraIcons($row),
                 $link,
-                $this->renderHostSummaries($row),
+                $this->renderHostSummaries($row)
             ];
         });
     }
 
-    protected function getExtraIcons($row)
+    protected function getExtraIcons(object $row)
     {
     }
 
-    protected function hasChosenColumn($name)
+    protected function hasChosenColumn(string $name): bool
     {
         return in_array($name, $this->getChosenColumnNames());
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createGroupingColumn(),
+
             $this->createColumn('cnt_hosts', $this->translate('Hosts'), 'COUNT(*)')
-                ->setRenderer(function ($row) {
-                    return Html::tag('td', ['class' => 'text-right'], $row->cnt_hosts);
-                })
+                ->setRenderer(fn($row) => Html::tag('td', ['class' => 'text-right'], $row->cnt_hosts))
                 ->setDefaultSortDirection('DESC'),
-            $this->createColumn(
-                'hosts_status',
-                $this->translate('Hosts Status'),
-                $this->getHostCountColumns()
-            )->setRenderer(function ($row) {
-                $result = [];
-                $uuid = Uuid::fromBytes($row->uuid)->toString();
-                foreach (['green', 'gray', 'yellow', 'red'] as $state) {
-                    $column = "hosts_cnt_overall_$state";
-                    if ($row->$column > 0) {
-                        $result[] = Link::create($row->$column, $this->baseUrlHosts, [
-                            'vcenter'        => $uuid,
-                            'overall_status' => $state
-                        ], ['class' => ['state', $state]]);
+
+            $this->createColumn('hosts_status', $this->translate('Hosts Status'), $this->getHostCountColumns())
+                ->setRenderer(function ($row) {
+                    $result = [];
+                    $uuid = Uuid::fromBytes($row->uuid)->toString();
+                    foreach (['green', 'gray', 'yellow', 'red'] as $state) {
+                        $column = "hosts_cnt_overall_$state";
+                        if ($row->$column > 0) {
+                            $result[] = Link::create($row->$column, $this->baseUrlHosts, [
+                                'vcenter'        => $uuid,
+                                'overall_status' => $state
+                            ], ['class' => ['state', $state]]);
+                        }
+                    }
+
+                    if (empty($result)) {
+                        return '-';
                     }
-                }
 
-                if (empty($result)) {
-                    return '-';
-                } else {
                     return $result;
-                }
-            })->setSortExpression([
-                "SUM(CASE WHEN ho.overall_status = 'red' THEN 1 ELSE 0 END)",
-                "SUM(CASE WHEN ho.overall_status = 'yellow' THEN 1 ELSE 0 END)",
-                "SUM(CASE WHEN ho.overall_status = 'gray' THEN 1 ELSE 0 END)",
-                "SUM(CASE WHEN ho.overall_status = 'green' THEN 1 ELSE 0 END)",
-            ])->setDefaultSortDirection('DESC'),
+                })
+                ->setSortExpression([
+                    "SUM(CASE WHEN ho.overall_status = 'red' THEN 1 ELSE 0 END)",
+                    "SUM(CASE WHEN ho.overall_status = 'yellow' THEN 1 ELSE 0 END)",
+                    "SUM(CASE WHEN ho.overall_status = 'gray' THEN 1 ELSE 0 END)",
+                    "SUM(CASE WHEN ho.overall_status = 'green' THEN 1 ELSE 0 END)"
+                ])
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('cpu', $this->translate('CPU'), [
                 'used_mhz'  => 'SUM(hqs.overall_cpu_usage)',
-                'total_mhz' => 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)',
-            ])->setRenderer(function ($row) {
-                $bar = new CpuUsage($row->used_mhz, $row->total_mhz);
-                if ($this->hasChosenColumn('overall_cpu_usage') || $this->hasChosenColumn('hardware_cpu_mhz')) {
-                    $bar->showLabels(false);
-                }
-                return $bar;
-            })->setSortExpression(
-                'SUM(hqs.overall_cpu_usage) / SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)'
-            )->setDefaultSortDirection('DESC'),
-            $this->createColumn('overall_cpu_usage', $this->translate('Used'), 'SUM(hqs.overall_cpu_usage)')
+                'total_mhz' => 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)'
+            ])
                 ->setRenderer(function ($row) {
-                    return Format::mhz($row->overall_cpu_usage);
-                })->setDefaultSortDirection('DESC'),
+                    $bar = new CpuUsage($row->used_mhz, $row->total_mhz);
+                    if ($this->hasChosenColumn('overall_cpu_usage') || $this->hasChosenColumn('hardware_cpu_mhz')) {
+                        $bar->showLabels(false);
+                    }
+
+                    return $bar;
+                })
+                ->setSortExpression('SUM(hqs.overall_cpu_usage) / SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)')
+                ->setDefaultSortDirection('DESC'),
+
+            $this->createColumn('overall_cpu_usage', $this->translate('Used'), 'SUM(hqs.overall_cpu_usage)')
+                ->setRenderer(fn($row) => Format::mhz($row->overall_cpu_usage))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn(
                 'hardware_cpu_mhz',
                 $this->translate('Capacity'),
                 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)'
-            )->setRenderer(function ($row) {
-                return Format::mhz($row->hardware_cpu_mhz);
-            })->setDefaultSortDirection('DESC'),
+            )
+                ->setRenderer(fn($row) => Format::mhz($row->hardware_cpu_mhz))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('hardware_cpu_cores', $this->translate('Cores'), 'SUM(h.hardware_cpu_cores)')
-                ->setRenderer(function ($row) {
-                    return Html::tag('td', ['class' => 'text-right'], $row->hardware_cpu_cores);
-                })
+                ->setRenderer(fn($row) => Html::tag('td', ['class' => 'text-right'], $row->hardware_cpu_cores))
                 ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('memory', $this->translate('Memory'), [
                 'used_mb'  => 'SUM(hqs.overall_memory_usage_mb)',
-                'total_mb' => 'SUM(h.hardware_memory_size_mb)',
-            ])->setRenderer(function ($row) {
-                $bar = new MemoryUsage($row->used_mb, $row->total_mb);
-                if ($this->hasChosenColumn('overall_memory_usage') || $this->hasChosenColumn('hardware_memorymb')) {
-                    $bar->showLabels(false);
-                }
-                return $bar;
-            })->setSortExpression(
-                'AVG(hqs.overall_memory_usage_mb / h.hardware_memory_size_mb)'
-            )->setDefaultSortDirection('DESC'),
-            $this->createColumn('overall_memory_usage', $this->translate('Used'), 'SUM(hqs.overall_memory_usage_mb)')
+                'total_mb' => 'SUM(h.hardware_memory_size_mb)'
+            ])
                 ->setRenderer(function ($row) {
-                    return Format::mBytes($row->overall_memory_usage);
-                })->setDefaultSortDirection('DESC'),
+                    $bar = new MemoryUsage($row->used_mb, $row->total_mb);
+                    if ($this->hasChosenColumn('overall_memory_usage') || $this->hasChosenColumn('hardware_memorymb')) {
+                        $bar->showLabels(false);
+                    }
+                    return $bar;
+                })
+                ->setSortExpression('AVG(hqs.overall_memory_usage_mb / h.hardware_memory_size_mb)')
+                ->setDefaultSortDirection('DESC'),
+
+            $this->createColumn('overall_memory_usage', $this->translate('Used'), 'SUM(hqs.overall_memory_usage_mb)')
+                ->setRenderer(fn($row) => Format::mBytes($row->overall_memory_usage))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('hardware_memorymb', $this->translate('Capacity'), 'SUM(h.hardware_memory_size_mb)')
-                ->setRenderer(function ($row) {
-                    return Format::mBytes($row->hardware_memorymb);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::mBytes($row->hardware_memorymb))
+                ->setDefaultSortDirection('DESC')
 
             /*
              // Not yet, this was an early prototype based no monitoring vars
@@ -198,18 +186,18 @@ protected function initialize()
         ]);
     }
 
-    protected function getHostCountColumns()
+    protected function getHostCountColumns(): array
     {
         return [
-            'hosts_cnt' => 'COUNT(*)',
+            'hosts_cnt'                => 'COUNT(*)',
             'hosts_cnt_overall_gray'   => "SUM(CASE WHEN ho.overall_status = 'gray' THEN 1 ELSE 0 END)",
             'hosts_cnt_overall_green'  => "SUM(CASE WHEN ho.overall_status = 'green' THEN 1 ELSE 0 END)",
             'hosts_cnt_overall_yellow' => "SUM(CASE WHEN ho.overall_status = 'yellow' THEN 1 ELSE 0 END)",
-            'hosts_cnt_overall_red'    => "SUM(CASE WHEN ho.overall_status = 'red' THEN 1 ELSE 0 END)",
+            'hosts_cnt_overall_red'    => "SUM(CASE WHEN ho.overall_status = 'red' THEN 1 ELSE 0 END)"
         ];
     }
 
-    protected function renderHostSummaries($row)
+    protected function renderHostSummaries(object $row): ?array
     {
         $params = $this->getFilterParams($row);
 
@@ -231,9 +219,12 @@ protected function renderHostSummaries($row)
             foreach (['red', 'yellow', 'gray', 'green'] as $state) {
                 $column = "hosts_cnt_overall_$state";
                 if ($row->$column > 0) {
-                    $result[] = Link::create($row->$column, 'vspheredb/hosts', $params + [
-                            'overall_status' => $state
-                        ], ['class' => ['state', $state]]);
+                    $result[] = Link::create(
+                        $row->$column,
+                        'vspheredb/hosts',
+                        $params + ['overall_status' => $state],
+                        ['class' => ['state', $state]]
+                    );
                 }
             }
         }
@@ -241,13 +232,14 @@ protected function renderHostSummaries($row)
         if (empty($result)) {
             return null;
         }
+
         return [
             Html::tag('br'),
-            Html::tag('small', $result),
+            Html::tag('small', $result)
         ];
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             $this->groupByAlias,
diff --git a/library/Vspheredb/Web/Table/Objects/HostsTable.php b/library/Vspheredb/Web/Table/Objects/HostsTable.php
index 67451aac..0d54a5df 100644
--- a/library/Vspheredb/Web/Table/Objects/HostsTable.php
+++ b/library/Vspheredb/Web/Table/Objects/HostsTable.php
@@ -3,156 +3,164 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
 use gipfl\IcingaWeb2\Link;
+use gipfl\ZfDb\Select;
 use Icinga\Date\DateFormatter;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
+use Icinga\Module\Vspheredb\Format;
 use Icinga\Module\Vspheredb\Util;
 use Icinga\Module\Vspheredb\Web\Widget\BiosInfo;
 use Icinga\Module\Vspheredb\Web\Widget\CpuUsage;
 use Icinga\Module\Vspheredb\Web\Widget\MemoryUsage;
 use Icinga\Module\Vspheredb\Web\Widget\PowerStateRenderer;
 use Icinga\Module\Vspheredb\Web\Widget\ServiceTagRenderer;
-use Icinga\Module\Vspheredb\Format;
+use Zend_Db_Select;
 
 class HostsTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/host';
+    protected ?string $baseUrl = 'vspheredb/host';
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $serviceTagRenderer = new ServiceTagRenderer();
         $powerStateRenderer = new PowerStateRenderer();
         $this->addAvailableColumns([
             $this->createOverallStatusColumn(),
+
             $this->createColumn('runtime_power_state', $this->translate('Power'), 'h.runtime_power_state')
                 ->setRenderer($powerStateRenderer),
+
             $this->createObjectNameColumn(),
+
             $this->createColumn('sysinfo_vendor', $this->translate('Vendor'), 'h.sysinfo_vendor'),
+
             $this->createColumn('sysinfo_model', $this->translate('Model'), 'h.sysinfo_model'),
+
             $this->createColumn('vcenter_name', $this->translate('vCenter / ESXi'), 'vc.name'),
+
             $this->createColumn('bios_version', $this->translate('BIOS Version'), 'h.bios_version'),
+
             $this->createColumn('bios_release_date', $this->translate('BIOS Release Date'), 'h.bios_release_date')
-                ->setRenderer(function ($row) {
-                    return DateFormatter::formatDate(strtotime($row->bios_release_date));
-                }),
+                ->setRenderer(fn($row) => DateFormatter::formatDate(strtotime($row->bios_release_date))),
+
             $this->createColumn('service_tag', $this->translate('Service Tag'), [
                 'service_tag'    => 'h.service_tag',
-                'sysinfo_vendor' => 'h.sysinfo_vendor',
-            ])->setRenderer($serviceTagRenderer),
+                'sysinfo_vendor' => 'h.sysinfo_vendor'
+            ])
+                ->setRenderer($serviceTagRenderer),
+
             $this->createColumn('product_api_version', $this->translate('API Version'), [
-                'product_api_version' => 'h.product_api_version',
+                'product_api_version' => 'h.product_api_version'
             ]),
+
             $this->createColumn('cpu_usage', $this->translate('CPU Usage'), [
                 'cpu_usage' => 'hqs.overall_cpu_usage',
-                'cpu_total' => '(hardware_cpu_cores * hardware_cpu_mhz)',
-            ])->setRenderer(function ($row) {
-                return new CpuUsage($row->cpu_usage, $row->cpu_total);
-            })->setSortExpression(
-                'hqs.overall_cpu_usage / (h.hardware_cpu_cores * h.hardware_cpu_mhz)'
-            )->setDefaultSortDirection('DESC'),
+                'cpu_total' => '(hardware_cpu_cores * hardware_cpu_mhz)'
+            ])
+                ->setRenderer(fn($row) => new CpuUsage($row->cpu_usage, $row->cpu_total))
+                ->setSortExpression('hqs.overall_cpu_usage / (h.hardware_cpu_cores * h.hardware_cpu_mhz)')
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('memory_usage', $this->translate('Memory Usage'), [
                 'hardware_memory_size_mb' => 'h.hardware_memory_size_mb',
-                'memory_usage_mb'         => 'hqs.overall_memory_usage_mb',
-            ])->setRenderer(function ($row) {
-                return new MemoryUsage($row->memory_usage_mb, $row->hardware_memory_size_mb);
-            })->setSortExpression(
-                '(hqs.overall_memory_usage_mb / h.hardware_memory_size_mb)'
-            )->setDefaultSortDirection('DESC'),
+                'memory_usage_mb'         => 'hqs.overall_memory_usage_mb'
+            ])
+                ->setRenderer(fn($row) => new MemoryUsage($row->memory_usage_mb, $row->hardware_memory_size_mb))
+                ->setSortExpression('(hqs.overall_memory_usage_mb / h.hardware_memory_size_mb)')
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('hardware_cpu_cores', $this->translate('CPU Cores'), 'h.hardware_cpu_cores')
                 ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('vms_overall_status', $this->translate('VM Status'), [
                 'vms_cnt_overall_gray'   => 'vms.vms_cnt_overall_gray',
                 'vms_cnt_overall_green'  => 'vms.vms_cnt_overall_green',
                 'vms_cnt_overall_yellow' => 'vms.vms_cnt_overall_yellow',
-                'vms_cnt_overall_red'    => 'vms.vms_cnt_overall_red',
-            ])->setRenderer(function ($row) {
-                $result = [];
-                foreach (['red', 'yellow', 'gray', 'green'] as $state) {
-                    $column = "vms_cnt_overall_$state";
-                    if ($row->$column > 0) {
-                        $result[] = Link::create(
-                            $row->$column,
-                            'vspheredb/host/vms',
-                            [
-                                'uuid'           => Util::niceUuid($row->uuid),
-                                'overall_status' => $state
-                            ],
-                            ['class' => ['state', $state]]
-                        );
+                'vms_cnt_overall_red'    => 'vms.vms_cnt_overall_red'
+            ])
+                ->setRenderer(function ($row) {
+                    $result = [];
+                    foreach (['red', 'yellow', 'gray', 'green'] as $state) {
+                        $column = "vms_cnt_overall_$state";
+                        if ($row->$column > 0) {
+                            $result[] = Link::create(
+                                $row->$column,
+                                'vspheredb/host/vms',
+                                [
+                                    'uuid'           => Util::niceUuid($row->uuid),
+                                    'overall_status' => $state
+                                ],
+                                ['class' => ['state', $state]]
+                            );
+                        }
+                    }
+
+                    if (empty($result)) {
+                        return '-';
                     }
-                }
 
-                if (empty($result)) {
-                    return '-';
-                } else {
                     return $result;
-                }
-            })->setSortExpression([
-                'vms.vms_cnt_overall_red',
-                'vms.vms_cnt_overall_yellow',
-                'vms.vms_cnt_overall_gray',
-                'vms.vms_cnt_overall_green',
-            ])->setDefaultSortDirection('DESC'),
+                })
+                ->setSortExpression([
+                    'vms.vms_cnt_overall_red',
+                    'vms.vms_cnt_overall_yellow',
+                    'vms.vms_cnt_overall_gray',
+                    'vms.vms_cnt_overall_green'
+                ])
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('vms_cnt_cpu', $this->translate('VM CPUs'), 'vms.cnt_cpu')
                 ->setDefaultSortDirection('DESC'),
+
             $this->createColumn(
                 'pcpu_vcpu_ration',
                 $this->translate('vCPU/pCPU'),
                 '(vms.cnt_cpu / h.hardware_cpu_cores)'
-            )->setRenderer(function ($row) {
-                return sprintf('%.3g:1', $row->pcpu_vcpu_ration);
-            })->setDefaultSortDirection('DESC'),
+            )
+                ->setRenderer(fn($row) => sprintf('%.3g:1', $row->pcpu_vcpu_ration))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('hardware_memory_size_mb', $this->translate('Memory'), 'h.hardware_memory_size_mb')
-                ->setRenderer(function ($row) {
-                    return Format::mBytes($row->hardware_memory_size_mb);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::mBytes($row->hardware_memory_size_mb))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('vms_memorymb', $this->translate('VMs Memory'), 'vms.memorymb')
-                ->setRenderer(function ($row) {
-                    return Format::mBytes($row->vms_memorymb);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::mBytes($row->vms_memorymb))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('vms_cnt', $this->translate('VMs'), 'vms.cnt')
                 ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('spectre_meltdown', $this->translate('Spectre / Meltdown'), [
                 'sysinfo_vendor'    => 'h.sysinfo_vendor',
                 'sysinfo_model'     => 'h.sysinfo_model',
                 'bios_version'      => 'h.bios_version',
-                'bios_release_date' => 'h.bios_release_date',
-            ])->setRenderer(function ($row) {
-                $host = HostSystem::create([
+                'bios_release_date' => 'h.bios_release_date'
+            ])
+                ->setRenderer(fn($row) => new BiosInfo(HostSystem::create([
                     'sysinfo_vendor'    => $row->sysinfo_vendor,
                     'sysinfo_model'     => $row->sysinfo_model,
                     'bios_version'      => $row->bios_version,
-                    'bios_release_date' => $row->bios_release_date,
-                ]);
-
-                return new BiosInfo($host);
-            }),
-            $this->createColumn('uptime', $this->translate('Uptime'), [
-                'uptime' => 'hqs.uptime',
-            ])->setRenderer(function ($row) {
-                if ($row->uptime === null) {
-                    return null;
-                }
-
-                return DateFormatter::formatDuration($row->uptime);
-            }),
+                    'bios_release_date' => $row->bios_release_date
+                ]))),
 
+            $this->createColumn('uptime', $this->translate('Uptime'), ['uptime' => 'hqs.uptime'])
+                ->setRenderer(fn($row) => $row->uptime === null ? null : DateFormatter::formatDuration($row->uptime))
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'object_name',
             'cpu_usage',
-            'memory_usage',
+            'memory_usage'
         ];
     }
 
-    protected function createVmSubQuery()
+    protected function createVmSubQuery(): Select|Zend_Db_Select
     {
-        return $this->db()->select()->from(
-            ['vc' => 'virtual_machine'],
-            [
+        return $this->db()->select()
+            ->from(['vc' => 'virtual_machine'], [
                 'cnt'                    => 'COUNT(*)',
                 'cnt_cpu'                => 'SUM(vc.hardware_numcpu)',
                 'memorymb'               => 'SUM(vc.hardware_memorymb)',
@@ -160,56 +168,37 @@ protected function createVmSubQuery()
                 'vms_cnt_overall_gray'   => "SUM(CASE WHEN vo.overall_status = 'gray' THEN 1 ELSE 0 END)",
                 'vms_cnt_overall_green'  => "SUM(CASE WHEN vo.overall_status = 'green' THEN 1 ELSE 0 END)",
                 'vms_cnt_overall_yellow' => "SUM(CASE WHEN vo.overall_status = 'yellow' THEN 1 ELSE 0 END)",
-                'vms_cnt_overall_red'    => "SUM(CASE WHEN vo.overall_status = 'red' THEN 1 ELSE 0 END)",
-            ]
-        )->join(
-            ['vo' => 'object'],
-            'vo.uuid = vc.uuid',
-            []
-        )->group('vc.runtime_host_uuid');
+                'vms_cnt_overall_red'    => "SUM(CASE WHEN vo.overall_status = 'red' THEN 1 ELSE 0 END)"
+            ])
+            ->join(['vo' => 'object'], 'vo.uuid = vc.uuid', [])
+            ->group('vc.runtime_host_uuid');
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
         $columns = $this->getRequiredDbColumns();
         $wantsVms = false;
         $wantsVCenter = false;
         foreach ($columns as $column) {
-            if (preg_match('/^\(?vms\./', $column)) {
+            if (str_starts_with($column, 'vms.') || str_starts_with($column, '(vms.')) {
                 $wantsVms = true;
                 break;
             }
-            if (substr($column, 0, 3) === 'vc.') {
+            if (str_starts_with($column, 'vc.')) {
                 $wantsVCenter = true;
             }
         }
 
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $columns
-        )->join(
-            ['h' => 'host_system'],
-            'o.uuid = h.uuid',
-            []
-        )->joinLeft(
-            ['hqs' => 'host_quick_stats'],
-            'h.uuid = hqs.uuid',
-            []
-        );
+        $query = $this->db()->select()
+            ->from(['o' => 'object'], $columns)
+            ->join(['h' => 'host_system'], 'o.uuid = h.uuid', [])
+            ->joinLeft(['hqs' => 'host_quick_stats'], 'h.uuid = hqs.uuid', []);
 
         if ($wantsVms) {
-            $query->joinLeft(
-                ['vms' => $this->createVmSubQuery()],
-                'vms.runtime_host_uuid = h.uuid',
-                []
-            );
+            $query->joinLeft(['vms' => $this->createVmSubQuery()], 'vms.runtime_host_uuid = h.uuid', []);
         }
         if ($wantsVCenter) {
-            $query->join(
-                ['vc' => 'vcenter'],
-                'vc.instance_uuid = h.vcenter_uuid',
-                []
-            );
+            $query->join(['vc' => 'vcenter'], 'vc.instance_uuid = h.vcenter_uuid', []);
         }
 
         return $query;
diff --git a/library/Vspheredb/Web/Table/Objects/NetworkAdaptersTable.php b/library/Vspheredb/Web/Table/Objects/NetworkAdaptersTable.php
index 6421a9df..06e10b29 100644
--- a/library/Vspheredb/Web/Table/Objects/NetworkAdaptersTable.php
+++ b/library/Vspheredb/Web/Table/Objects/NetworkAdaptersTable.php
@@ -2,64 +2,53 @@
 
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\DbObject\DistributedVirtualPortgroup;
+use Zend_Db_Select;
 
 class NetworkAdaptersTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/vm';
+    protected ?string $baseUrl = 'vspheredb/vm';
 
-    /** @var DistributedVirtualPortgroup|null */
-    protected $portGroup;
+    protected ?DistributedVirtualPortgroup $portGroup = null;
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $this->getRequiredDbColumns()
-        )->join(
-            ['vm' => 'virtual_machine'],
-            'o.uuid = vm.uuid',
-            []
-        )->join(
-            ['vh' => 'vm_hardware'],
-            'vh.vm_uuid = vm.uuid',
-            []
-        )->join(
-            ['vna' => 'vm_network_adapter'],
-            'vna.vm_uuid = vh.vm_uuid AND vna.hardware_key = vh.hardware_key',
-            []
-        );
+        $query = $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->join(['vm' => 'virtual_machine'], 'o.uuid = vm.uuid', [])
+            ->join(['vh' => 'vm_hardware'], 'vh.vm_uuid = vm.uuid', [])
+            ->join(
+                ['vna' => 'vm_network_adapter'],
+                'vna.vm_uuid = vh.vm_uuid AND vna.hardware_key = vh.hardware_key',
+                []
+            );
 
         if ($this->portGroup) {
-            $query->where(
-                'portgroup_uuid = ?',
-                $this->portGroup->get('uuid')
-            );
+            $query->where('portgroup_uuid = ?', $this->portGroup->get('uuid'));
         }
 
         return $query;
     }
 
-    public function filterPortGroup(DistributedVirtualPortgroup $portGroup)
+    public function filterPortGroup(DistributedVirtualPortgroup $portGroup): static
     {
         $this->portGroup = $portGroup;
 
         return $this;
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createOverallStatusColumn(),
             $this->createColumn('port_key', $this->translate('Port'), 'vna.port_key'),
             $this->createObjectNameColumn(),
-            $this->createColumn('label', $this->translate('Interface'), [
-                'vh.label',
-            ]),
+            $this->createColumn('label', $this->translate('Interface'), ['vh.label'])
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'port_key',
diff --git a/library/Vspheredb/Web/Table/Objects/ObjectsTable.php b/library/Vspheredb/Web/Table/Objects/ObjectsTable.php
index 38d470be..330c7aeb 100644
--- a/library/Vspheredb/Web/Table/Objects/ObjectsTable.php
+++ b/library/Vspheredb/Web/Table/Objects/ObjectsTable.php
@@ -7,6 +7,7 @@
 use Icinga\Module\Vspheredb\Db\DbUtil;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Module\Vspheredb\Web\Table\BaseTable;
+use Icinga\Module\Vspheredb\Web\Table\SimpleColumn;
 use Icinga\Module\Vspheredb\Web\Table\TableWithParentFilter;
 use Icinga\Module\Vspheredb\Web\Table\TableWithVCenterFilter;
 use Icinga\Module\Vspheredb\Web\Widget\OverallStatusRenderer;
@@ -14,9 +15,7 @@
 
 abstract class ObjectsTable extends BaseTable implements TableWithVCenterFilter, TableWithParentFilter
 {
-    protected $searchColumns = [
-        'object_name',
-    ];
+    protected $searchColumns = ['object_name'];
 
     /** @deprecated  */
     protected $filterVCenter;
@@ -24,35 +23,32 @@ abstract class ObjectsTable extends BaseTable implements TableWithVCenterFilter,
     /** @deprecated  */
     protected $parentUuids;
 
-    protected $baseUrl;
+    protected ?string $baseUrl = null;
 
-    protected $overallStatusRenderer;
+    protected ?OverallStatusRenderer $overallStatusRenderer = null;
 
-    public function filterParentUuids(array $uuids)
+    public function filterParentUuids(array $uuids): static
     {
         $this->getQuery()->where('o.parent_uuid IN (?)', $uuids);
 
         return $this;
     }
 
-    public function filterVCenter(VCenter $vCenter): self
+    public function filterVCenter(VCenter $vCenter): static
     {
         return $this->filterVCenterUuids([$vCenter->getUuid()]);
     }
 
-    public function filterVCenterUuids(array $uuids): self
+    public function filterVCenterUuids(array $uuids): static
     {
         if (empty($uuids)) {
             $this->getQuery()->where('1 = 0');
+
             return $this;
         }
 
         $db = $this->db();
-        if ($this instanceof VCenterSummaryTable) {
-            $column = 'vc.instance_uuid';
-        } else {
-            $column = 'o.vcenter_uuid';
-        }
+        $column = $this instanceof VCenterSummaryTable ? 'vc.instance_uuid' : 'o.vcenter_uuid';
         if (count($uuids) === 1) {
             $this->getQuery()->where("$column = ?", DbUtil::quoteBinaryCompat(array_shift($uuids), $db));
         } else {
@@ -62,28 +58,24 @@ public function filterVCenterUuids(array $uuids): self
         return $this;
     }
 
-    protected function overallStatusRenderer()
+    protected function overallStatusRenderer(): OverallStatusRenderer
     {
-        if ($this->overallStatusRenderer === null) {
-            $this->overallStatusRenderer = new OverallStatusRenderer();
-        }
-
-        return $this->overallStatusRenderer;
+        return $this->overallStatusRenderer ??= new OverallStatusRenderer();
     }
 
-    protected function createOverallStatusColumn()
+    protected function createOverallStatusColumn(): SimpleColumn
     {
         return $this->createColumn('overall_status', $this->translate('Status'), 'o.overall_status')
             ->setRenderer($this->overallStatusRenderer())
             ->setDefaultSortDirection('DESC');
     }
 
-    protected function createObjectNameColumn()
+    protected function createObjectNameColumn(): SimpleColumn
     {
         return $this->createColumn('object_name', $this->translate('Name'), [
             'object_name'    => 'o.object_name',
             'overall_status' => 'o.overall_status',
-            'uuid'           => 'o.uuid',
+            'uuid'           => 'o.uuid'
         ])->setRenderer(function ($row) {
             $row->object_name = Anonymizer::anonymizeString($row->object_name);
             if (in_array('overall_status', $this->getChosenColumnNames())) {
@@ -92,15 +84,9 @@ protected function createObjectNameColumn()
                 $statusRenderer = $this->overallStatusRenderer();
                 $result = [$statusRenderer($row)];
             }
-            if ($this->baseUrl === null) {
-                $result[] = $row->object_name;
-            } else {
-                $result[] = Link::create(
-                    $row->object_name,
-                    $this->baseUrl,
-                    ['uuid' => Uuid::fromBytes($row->uuid)->toString()]
-                );
-            }
+            $result[] = $this->baseUrl === null
+                ? $row->object_name
+                : Link::create($row->object_name, $this->baseUrl, ['uuid' => Uuid::fromBytes($row->uuid)->toString()]);
 
             return $result;
         });
diff --git a/library/Vspheredb/Web/Table/Objects/PercentObjectsTable.php b/library/Vspheredb/Web/Table/Objects/PercentObjectsTable.php
new file mode 100644
index 00000000..4d60b4d7
--- /dev/null
+++ b/library/Vspheredb/Web/Table/Objects/PercentObjectsTable.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Icinga\Module\Vspheredb\Web\Table\Objects;
+
+use Icinga\Util\Format;
+
+abstract class PercentObjectsTable extends ObjectsTable
+{
+    protected function formatBytesPercent(object $row, string $name): string
+    {
+        $bytes = $row->$name;
+        $percent = $row->{"{$name}_percent"};
+
+        return sprintf('%s (%s)', Format::bytes($bytes, Format::STANDARD_IEC), $this->formatPercent($percent));
+    }
+
+    protected function formatPercent(string $value): string
+    {
+        return sprintf('%0.2f%%', $value);
+    }
+}
diff --git a/library/Vspheredb/Web/Table/Objects/PortGroupsTable.php b/library/Vspheredb/Web/Table/Objects/PortGroupsTable.php
index fe1310f5..8dfc3e9b 100644
--- a/library/Vspheredb/Web/Table/Objects/PortGroupsTable.php
+++ b/library/Vspheredb/Web/Table/Objects/PortGroupsTable.php
@@ -3,80 +3,74 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
 use gipfl\Json\JsonString;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\DbObject\DistributedVirtualSwitch;
 use ipl\Html\Html;
+use Zend_Db_Select;
 
 class PortGroupsTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/portgroup';
+    protected ?string $baseUrl = 'vspheredb/portgroup';
 
-    /** @var DistributedVirtualSwitch|null */
-    protected $switch;
+    protected ?DistributedVirtualSwitch $switch = null;
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $this->getRequiredDbColumns()
-        )->join(
-            ['vdp' => 'distributed_virtual_portgroup'],
-            'o.uuid = vdp.uuid',
-            []
-        );
+        $query = $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->join(['vdp' => 'distributed_virtual_portgroup'], 'o.uuid = vdp.uuid', []);
 
         if ($this->switch) {
-            $query->where(
-                'distributed_virtual_switch_uuid = ?',
-                $this->switch->get('uuid')
-            );
+            $query->where('distributed_virtual_switch_uuid = ?', $this->switch->get('uuid'));
         }
 
         return $query;
     }
 
-    public function filterSwitch(DistributedVirtualSwitch $switch)
+    public function filterSwitch(DistributedVirtualSwitch $switch): static
     {
         $this->switch = $switch;
 
         return $this;
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createOverallStatusColumn(),
             $this->createObjectNameColumn(),
             $this->createColumn('vlan', $this->translate('VLAN'), [
                 'vdp.vlan',
-                'vdp.vlan_ranges',
-            ])->setRenderer(function ($row) {
-                if ($row->vlan === null) {
+                'vdp.vlan_ranges'
+            ])
+                ->setRenderer(function ($row) {
+                    if ($row->vlan !== null) {
+                        return $row->vlan;
+                    }
+
                     if ($row->vlan_ranges === null) {
                         return '-';
-                    } else {
-                        $ranges = [];
-                        foreach (JsonString::decode($row->vlan_ranges) as $range) {
-                            if (! empty($ranges)) {
-                                $ranges[] = Html::tag('br');
-                            }
-                            $ranges[] = sprintf(
-                                '%s - %s',
-                                $range->start,
-                                $range->end
-                            );
-                        }
+                    }
 
-                        return $ranges;
+                    $ranges = [];
+                    foreach (JsonString::decode($row->vlan_ranges) as $range) {
+                        if (! empty($ranges)) {
+                            $ranges[] = Html::tag('br');
+                        }
+                        $ranges[] = sprintf(
+                            '%s - %s',
+                            $range->start,
+                            $range->end
+                        );
                     }
-                } else {
-                    return $row->vlan;
-                }
-            }),
-            $this->createColumn('num_ports', $this->translate('Ports'), 'vdp.num_ports'),
+
+                    return $ranges;
+                }),
+            $this->createColumn('num_ports', $this->translate('Ports'), 'vdp.num_ports')
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'overall_status',
diff --git a/library/Vspheredb/Web/Table/Objects/ResourcePoolsTable.php b/library/Vspheredb/Web/Table/Objects/ResourcePoolsTable.php
index 1c812129..23f747eb 100644
--- a/library/Vspheredb/Web/Table/Objects/ResourcePoolsTable.php
+++ b/library/Vspheredb/Web/Table/Objects/ResourcePoolsTable.php
@@ -2,42 +2,40 @@
 
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
+use gipfl\ZfDb\Select;
+use Zend_Db_Select;
+
 class ResourcePoolsTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/resourcepool';
+    protected ?string $baseUrl = 'vspheredb/resourcepool';
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createOverallStatusColumn(),
             $this->createObjectNameColumn(),
             $this->createColumn('cnt_vms', $this->translate('VMs'), 'COUNT(*)')
-                ->setDefaultSortDirection('DESC'),
+                ->setDefaultSortDirection('DESC')
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'overall_status',
             'object_name',
-            'cnt_vms',
+            'cnt_vms'
         ];
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $this->getRequiredDbColumns()
-        )->where('object_type = ?', 'ResourcePool');
+        $query = $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->where('object_type = ?', 'ResourcePool');
 
         if ($this->hasColumn('cnt_vms')) {
-            $query->joinLeft(
-                ['vm' => 'virtual_machine'],
-                'vm.resource_pool_uuid = o.uuid',
-                []
-            )->group('o.uuid');
+            $query->joinLeft(['vm' => 'virtual_machine'], 'vm.resource_pool_uuid = o.uuid', [])->group('o.uuid');
         }
 
         return $query;
diff --git a/library/Vspheredb/Web/Table/Objects/StoragePodTable.php b/library/Vspheredb/Web/Table/Objects/StoragePodTable.php
index d09146cc..07a6f37b 100644
--- a/library/Vspheredb/Web/Table/Objects/StoragePodTable.php
+++ b/library/Vspheredb/Web/Table/Objects/StoragePodTable.php
@@ -3,96 +3,76 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
 use gipfl\IcingaWeb2\Link;
-use Icinga\Module\Vspheredb\Db;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Util;
 use Icinga\Module\Vspheredb\Web\Widget\MemoryUsage;
 use Icinga\Util\Format;
 use ipl\Html\Html;
+use Zend_Db_Select;
 
-class StoragePodTable extends ObjectsTable
+class StoragePodTable extends PercentObjectsTable
 {
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createOverallStatusColumn(),
+
             $this->createColumn('object_name', $this->translate('Name'), [
-                'object_name'          => 'o.object_name',
-                'uuid'                 => 'o.uuid',
-                'cnt_datastore'        => 'COUNT(dso.uuid)',
-            ])->setRenderer(function ($row) {
-                $cntDs = (int) $row->cnt_datastore;
-                if ($cntDs === 0) {
-                    $dsCount = 'no datastore';
-                } elseif ($cntDs === 1) {
-                    $dsCount = '1 datastore';
-                } else {
-                    $dsCount = sprintf($this->translate('%s datastores'), $cntDs);
-                }
-                return Link::create(
-                    [
-                        $row->object_name,
-                        ' ',
-                        Html::tag('small', $dsCount)
-                    ],
-                    'vspheredb/datastores',
-                    Util::uuidParams($row->uuid)
-                );
-            }),
-            $this->createColumn('free_space', $this->translate('Free'), 'sp.free_space')
+                'object_name'   => 'o.object_name',
+                'uuid'          => 'o.uuid',
+                'cnt_datastore' => 'COUNT(dso.uuid)'
+            ])
                 ->setRenderer(function ($row) {
-                    return Format::bytes($row->free_space, Format::STANDARD_IEC);
+                    $cntDs = (int) $row->cnt_datastore;
+                    $dsCount = match ($cntDs) {
+                        0       => 'no datastore',
+                        1       => '1 datastore',
+                        default => sprintf($this->translate('%s datastores'), $cntDs)
+                    };
+
+                    return Link::create(
+                        [$row->object_name, ' ', Html::tag('small', $dsCount)],
+                        'vspheredb/datastores',
+                        Util::uuidParams($row->uuid)
+                    );
                 }),
+
+            $this->createColumn('free_space', $this->translate('Free'), 'sp.free_space')
+                ->setRenderer(fn($row) => Format::bytes($row->free_space, Format::STANDARD_IEC)),
+
             $this->createColumn('free_space_percent', $this->translate('Free (%)'), [
-                'free_space_percent'  => '(sp.free_space / sp.capacity) * 100'
-            ])->setRenderer(function ($row) {
-                return $this->formatPercent($row->free_space_percent);
-            }),
+                'free_space_percent' => '(sp.free_space / sp.capacity) * 100'
+            ])
+                ->setRenderer(fn($row) => $this->formatPercent($row->free_space_percent)),
+
             $this->createColumn('size', $this->translate('Size'), 'sp.capacity')
-                ->setRenderer(function ($row) {
-                    return Format::bytes($row->capacity, Format::STANDARD_IEC);
-                }),
+                ->setRenderer(fn($row) => Format::bytes($row->capacity, Format::STANDARD_IEC)),
+
             $this->createColumn('usage', $this->translate('Usage'), [
                 'uuid'       => 'o.uuid',
                 'free_space' => 'sp.free_space',
-                'capacity'   => 'sp.capacity',
-            ])->setRenderer(function ($row) {
-                /** @var Db $connection */
-                $div = 1024 * 1024;
-                $usage = new MemoryUsage(($row->capacity - $row->free_space) / $div, $row->capacity / $div);
+                'capacity'   => 'sp.capacity'
+            ])
+                ->setRenderer(function ($row) {
+                    $div = 1024 * 1024;
 
-                return $usage;
-            })->setSortExpression(
-                '1 - (sp.free_space / sp.capacity)'
-            )->setDefaultSortDirection('DESC'),
+                    return new MemoryUsage(($row->capacity - $row->free_space) / $div, $row->capacity / $div);
+                })
+                ->setSortExpression('1 - (sp.free_space / sp.capacity)')
+                ->setDefaultSortDirection('DESC')
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'overall_status',
             'object_name',
-            'usage',
+            'usage'
         ];
     }
 
-    protected function formatBytesPercent($row, $name)
-    {
-        $bytes = $row->$name;
-        $percent = $row->{"{$name}_percent"};
-        return sprintf(
-            '%s (%s)',
-            Format::bytes($bytes, Format::STANDARD_IEC),
-            $this->formatPercent($percent)
-        );
-    }
-
-    protected function formatPercent($value)
-    {
-        return sprintf('%0.2f%%', $value);
-    }
-
-    public function sortBy($columns)
+    public function sortBy(array|string $columns): static
     {
         parent::sortBy($columns);
 
@@ -101,28 +81,12 @@ public function sortBy($columns)
         return $this;
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $this->getRequiredDbColumns()
-        )->join(
-            ['sp' => 'storage_pod'],
-            'o.uuid = sp.uuid',
-            []
-        )->joinLeft(
-            ['dso' => 'object'],
-            'dso.parent_uuid= o.uuid',
-            []
-        )->group('o.uuid');
-
-        if ($this->parentUuids) {
-            $query->where('o.parent_uuid IN (?)', $this->parentUuids);
-        }
-        if ($this->filterVCenter) {
-            $query->where('o.vcenter_uuid = ?', $this->filterVCenter->getUuid());
-        }
-
-        return $query;
+        return $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->join(['sp' => 'storage_pod'], 'o.uuid = sp.uuid', [])
+            ->joinLeft(['dso' => 'object'], 'dso.parent_uuid= o.uuid', [])
+            ->group('o.uuid');
     }
 }
diff --git a/library/Vspheredb/Web/Table/Objects/SwitchesTable.php b/library/Vspheredb/Web/Table/Objects/SwitchesTable.php
index 11ddab74..3250ceb5 100644
--- a/library/Vspheredb/Web/Table/Objects/SwitchesTable.php
+++ b/library/Vspheredb/Web/Table/Objects/SwitchesTable.php
@@ -2,36 +2,32 @@
 
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
+use gipfl\ZfDb\Select;
+use Zend_Db_Select;
+
 class SwitchesTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/switch';
+    protected ?string $baseUrl = 'vspheredb/switch';
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $this->getRequiredDbColumns()
-        )->join(
-            ['vds' => 'distributed_virtual_switch'],
-            'o.uuid = vds.uuid',
-            []
-        );
-
-        return $query;
+        return $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->join(['vds' => 'distributed_virtual_switch'], 'o.uuid = vds.uuid', []);
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createOverallStatusColumn(),
             $this->createObjectNameColumn(),
             $this->createColumn('num_hosts', $this->translate('Hosts'), 'vds.num_hosts'),
             $this->createColumn('num_ports', $this->translate('Ports'), 'vds.num_ports'),
-            $this->createColumn('max_ports', $this->translate('Max Ports'), 'vds.max_ports'),
+            $this->createColumn('max_ports', $this->translate('Max Ports'), 'vds.max_ports')
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'overall_status',
diff --git a/library/Vspheredb/Web/Table/Objects/VCenterServersTable.php b/library/Vspheredb/Web/Table/Objects/VCenterServersTable.php
index 277a9689..073f5e4c 100644
--- a/library/Vspheredb/Web/Table/Objects/VCenterServersTable.php
+++ b/library/Vspheredb/Web/Table/Objects/VCenterServersTable.php
@@ -6,14 +6,19 @@
 use Evenement\EventEmitterTrait;
 use gipfl\IcingaWeb2\Icon;
 use gipfl\IcingaWeb2\Link;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Polling\ApiConnection;
 use Icinga\Module\Vspheredb\Web\Form\DisableServerForm;
 use Icinga\Module\Vspheredb\Web\Form\EnableServerForm;
 use Icinga\Module\Vspheredb\Web\Table\BaseTable;
 use Icinga\Module\Vspheredb\Web\Table\SimpleColumn;
+use ipl\Html\Attributes;
 use ipl\Html\Html;
 use ipl\Stdlib\Events;
-use Psr\Http\Message\RequestInterface;
+use ipl\Html\HtmlElement;
+use ipl\Html\Text;
+use Psr\Http\Message\ServerRequestInterface;
+use Zend_Db_Select;
 
 class VCenterServersTable extends BaseTable
 {
@@ -21,16 +26,16 @@ class VCenterServersTable extends BaseTable
 
     public const ON_FORM_ACTION = 'formAction';
 
-    protected $request;
+    protected ?ServerRequestInterface $request = null;
 
-    protected $serverConnections;
+    protected ?array $serverConnections = null;
 
-    public function setRequest(RequestInterface $request)
+    public function setRequest(ServerRequestInterface $request): void
     {
         $this->request = $request;
     }
 
-    public function setServerConnections($connections)
+    public function setServerConnections(?array $connections): void
     {
         $this->serverConnections = $connections;
     }
@@ -43,35 +48,22 @@ public function setServerConnections($connections)
      */
     protected function getConnectionStatusIcon(int $serverId, bool $enabled): Icon
     {
-        if (isset($this->serverConnections[$serverId])) {
-            $conn = end($this->serverConnections[$serverId]);
-            switch ($conn->state) {
-                case ApiConnection::STATE_CONNECTED:
-                    return Icon::create('ok');
-                case ApiConnection::STATE_LOGIN:
-                case ApiConnection::STATE_INIT:
-                    return Icon::create('spinner');
-                case ApiConnection::STATE_FAILING:
-                    return Icon::create('warning-empty');
-                case ApiConnection::STATE_STOPPING:
-                    return Icon::create('cancel');
-            }
-
-            return Icon::create('off');
-        } else {
-            if ($enabled) {
-                return Icon::create('help');
-            } else {
-                return Icon::create('off');
-            }
+        if (! isset($this->serverConnections[$serverId])) {
+            return $enabled ? Icon::create('help') : Icon::create('off');
         }
+
+        return match (end($this->serverConnections[$serverId])->state) {
+            ApiConnection::STATE_CONNECTED                        => Icon::create('ok'),
+            ApiConnection::STATE_LOGIN, ApiConnection::STATE_INIT => Icon::create('spinner'),
+            ApiConnection::STATE_FAILING                          => Icon::create('warning-empty'),
+            ApiConnection::STATE_STOPPING                         => Icon::create('cancel'),
+            default                                               => Icon::create('off')
+        };
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
-        $this->addAttributes([
-            'class' => 'table-vcenter-servers',
-        ]);
+        $this->addAttributes(Attributes::create(['class' => 'table-vcenter-servers']));
         $this->addAvailableColumns([
             (new SimpleColumn('server', $this->translate('Server'), [
                 'id'       => 'vcs.id',
@@ -79,44 +71,41 @@ protected function initialize()
                 'username' => 'vcs.username',
                 'scheme'   => 'vcs.scheme',
                 'enabled'  => 'vcs.enabled',
-                'vcenter'  => 'vc.name',
-            ]))->setRenderer(function ($row) {
-                $td = Html::tag('td', ['class' => 'column-server']);
-                $td->add(Link::create($this->makeUrl($row), 'vspheredb/vcenter/server', ['id' => $row->id]));
-                $td->add(Html::tag('br'));
-                $td->add($row->vcenter);
-
-                return $td;
-            })->setDefaultSortDirection('DESC'),
-            (new SimpleColumn('enabled', $this->translate('Status'), [
-                'vcs.enabled',
-                'vcs.id',
-            ]))->setRenderer(function ($row) {
-                if ($row->enabled === 'y') {
-                    $form = new DisableServerForm($row->id, $this->db());
-                } else {
-                    $form = new EnableServerForm($row->id, $this->db());
-                }
-                $form->addAttributes([
-                    'data-base-target' => '_self'
-                ]);
-                $form->on($form::ON_SUCCESS, function () {
-                    $this->emit(self::ON_FORM_ACTION);
-                });
-                $form->handleRequest($this->request);
-                $form->ensureAssembled();
-                $td = Html::tag('td', [
-                    'class' => 'column-enabled'
-                ], $form);
-                if ($this->serverConnections !== null) {
-                    $td->add([' ', $this->getConnectionStatusIcon($row->id, $row->enabled === 'y'), ' ']);
-                }
-                return $td;
-            }),
+                'vcenter'  => 'vc.name'
+            ]))
+                ->setRenderer(function ($row) {
+                    return Html::tag('td', ['class' => 'column-server'])
+                        ->addHtml(
+                            Link::create($this->makeUrl($row), 'vspheredb/vcenter/server', ['id' => $row->id]),
+                            Html::tag('br'),
+                            new Text($row->vcenter)
+                        );
+                })
+                ->setDefaultSortDirection('DESC'),
+            (new SimpleColumn('enabled', $this->translate('Status'), ['vcs.enabled', 'vcs.id']))
+                ->setRenderer(function ($row) {
+                    $form = $row->enabled === 'y'
+                        ? new DisableServerForm($row->id, $this->db())
+                        : new EnableServerForm($row->id, $this->db());
+
+                    $form->addAttributes(Attributes::create(['data-base-target' => '_self']))
+                        ->on($form::ON_SUBMIT, function () {
+                            $this->emit(self::ON_FORM_ACTION);
+                        })
+                        ->handleRequest($this->request)
+                        ->ensureAssembled();
+
+                    $td = Html::tag('td', ['class' => 'column-enabled'], $form);
+                    if ($this->serverConnections !== null) {
+                        $td->add([' ', $this->getConnectionStatusIcon($row->id, $row->enabled === 'y'), ' ']);
+                    }
+
+                    return $td;
+                })
         ]);
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $tr = parent::renderRow($row);
         if ($row->enabled === 'n') {
@@ -126,26 +115,15 @@ public function renderRow($row)
         return $tr;
     }
 
-    protected function makeUrl($row)
+    protected function makeUrl(object $row): string
     {
-        return sprintf(
-            '%s://%s@%s',
-            $row->scheme,
-            rawurlencode($row->username),
-            $row->host
-        );
+        return sprintf('%s://%s@%s', $row->scheme, rawurlencode($row->username), $row->host);
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        return $this->db()->select()->from(
-            ['vcs' => 'vcenter_server'],
-            $this->getRequiredDbColumns()
-        )->joinLeft(
-            ['vc' => 'vcenter'],
-            // 'vc.instance_uuid = vcs.vcenter_uuid',
-            'vc.id = vcs.vcenter_id',
-            []
-        );
+        return $this->db()->select()
+            ->from(['vcs' => 'vcenter_server'], $this->getRequiredDbColumns())
+            ->joinLeft(['vc' => 'vcenter'], /* 'vc.instance_uuid = vcs.vcenter_uuid',*/ 'vc.id = vcs.vcenter_id', []);
     }
 }
diff --git a/library/Vspheredb/Web/Table/Objects/VCenterSummaryTable.php b/library/Vspheredb/Web/Table/Objects/VCenterSummaryTable.php
index 046b415d..d9f57161 100644
--- a/library/Vspheredb/Web/Table/Objects/VCenterSummaryTable.php
+++ b/library/Vspheredb/Web/Table/Objects/VCenterSummaryTable.php
@@ -3,32 +3,36 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
 use gipfl\IcingaWeb2\Link;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Format;
 use Icinga\Module\Vspheredb\Monitoring\Health\ServerConnectionInfo;
 use Icinga\Module\Vspheredb\Util;
+use Icinga\Module\Vspheredb\Web\Table\SimpleColumn;
 use Icinga\Module\Vspheredb\Web\Widget\CpuUsage;
 use Icinga\Module\Vspheredb\Web\Widget\MemoryUsage;
 use Icinga\Module\Vspheredb\Web\Widget\VCenterConnectionStatusIcon;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use Ramsey\Uuid\Uuid;
+use Zend_Db_Select;
 
 class VCenterSummaryTable extends ObjectsTable
 {
     protected $searchColumns = [
-        'name',
+        'name'
     ];
-    protected $baseUrl = 'vspheredb/vcenter';
+    protected ?string $baseUrl = 'vspheredb/vcenter';
 
-    protected $baseUrlHosts = 'vspheredb/hosts';
+    protected string $baseUrlHosts = 'vspheredb/hosts';
 
-    protected $groupBy = 'o.vcenter_uuid';
+    protected string $groupBy = 'o.vcenter_uuid';
 
-    protected $groupByAlias = 'name';
+    protected string $groupByAlias = 'name';
 
-    protected $nameColumn = 'vc.name';
+    protected string $nameColumn = 'vc.name';
 
-    /** @var array<int, array<int, ServerConnectionInfo>> */
-    protected $connections;
+    /** @var ?array<int, array<int, ServerConnectionInfo>> */
+    protected ?array $connections = null;
 
     /**
      * @param array<int, array<int, ServerConnectionInfo>> $connections
@@ -37,10 +41,11 @@ class VCenterSummaryTable extends ObjectsTable
     public function setConnections(array $connections): self
     {
         $this->connections = $connections;
+
         return $this;
     }
 
-    protected function getExtraIcons($row)
+    protected function getExtraIcons(object $row): ?HtmlElement
     {
         if ($this->connections === null) {
             return null;
@@ -59,174 +64,176 @@ protected function getExtraIcons($row)
         return $icons;
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             $this->groupByAlias,
             'cpu',
             'memory',
-            'datastore_usage',
+            'datastore_usage'
         ];
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->setAttribute('data-base-target', '_self');
-        $this->addAvailableColumns([
-            $this->createGroupingColumn(),
-        ]);
+        $this->addAvailableColumns([$this->createGroupingColumn()]);
         $this->addHostColumns();
         $this->addDatastoreColumns();
         $this->addVCenterColumns();
     }
 
-    protected function createGroupingColumn()
+    protected function createGroupingColumn(): SimpleColumn
     {
         return $this->createColumn($this->groupByAlias, $this->getGroupingTitle(), [
-                'name'         => $this->nameColumn,
-                'uuid'         => $this->groupBy,
-            ] + $this->getHostCountColumns())->setRenderer(function ($row) {
-                $link = Link::create(
+                'name' => $this->nameColumn,
+                'uuid' => $this->groupBy
+            ] + $this->getHostCountColumns())
+            ->setRenderer(fn($row) => [
+                $this->getExtraIcons($row),
+                Link::create(
                     $row->{$this->groupByAlias},
                     $this->baseUrl,
                     $this->getFilterParams($row),
                     ['data-base-target' => '_next']
-                );
-
-                return [
-                    $this->getExtraIcons($row),
-                    $link,
-                    $this->renderHostSummaries($row),
-                ];
-            });
+                ),
+                $this->renderHostSummaries($row)
+            ]);
     }
 
-    protected function hasChosenColumn($name)
+    protected function hasChosenColumn($name): bool
     {
         return in_array($name, $this->getChosenColumnNames());
     }
 
-    protected function addHostColumns()
+    protected function addHostColumns(): void
     {
         $this->addAvailableColumns([
             $this->createColumn('hosts_cnt', $this->translate('Hosts'), 'SUM(hosts_cnt)')
-                ->setRenderer(function ($row) {
-                    return Html::tag('td', ['class' => 'text-right'], $row->hosts_cnt);
-                })
+                ->setRenderer(fn($row) => Html::tag('td', ['class' => 'text-right'], $row->hosts_cnt))
                 ->setDefaultSortDirection('DESC'),
-            $this->createColumn(
-                'hosts_status',
-                $this->translate('Hosts Status'),
-                $this->getHostCountColumns()
-            )->setRenderer(function ($row) {
-                $result = [];
-                $uuid = Uuid::fromBytes($row->uuid)->toString();
-                foreach (['green', 'gray', 'yellow', 'red'] as $state) {
-                    $column = "hosts_cnt_overall_$state";
-                    if ($row->$column > 0) {
-                        $result[] = Link::create($row->$column, $this->baseUrlHosts, [
-                            'vcenter'        => $uuid,
-                            'overall_status' => $state
-                        ], ['class' => ['state', $state]]);
+
+            $this->createColumn('hosts_status', $this->translate('Hosts Status'), $this->getHostCountColumns())
+                ->setRenderer(function ($row) {
+                    $result = [];
+                    $uuid = Uuid::fromBytes($row->uuid)->toString();
+                    foreach (['green', 'gray', 'yellow', 'red'] as $state) {
+                        $column = "hosts_cnt_overall_$state";
+                        if ($row->$column > 0) {
+                            $result[] = Link::create(
+                                $row->$column,
+                                $this->baseUrlHosts,
+                                [
+                                    'vcenter'        => $uuid,
+                                    'overall_status' => $state
+                                ],
+                                ['class' => ['state', $state]]
+                            );
+                        }
+                    }
+
+                    if (empty($result)) {
+                        return '-';
                     }
-                }
 
-                if (empty($result)) {
-                    return '-';
-                } else {
                     return $result;
-                }
-            })->setSortExpression([
-                "SUM(CASE WHEN ho.overall_status = 'red' THEN 1 ELSE 0 END)",
-                "SUM(CASE WHEN ho.overall_status = 'yellow' THEN 1 ELSE 0 END)",
-                "SUM(CASE WHEN ho.overall_status = 'gray' THEN 1 ELSE 0 END)",
-                "SUM(CASE WHEN ho.overall_status = 'green' THEN 1 ELSE 0 END)",
-            ])->setDefaultSortDirection('DESC'),
+                })
+                ->setSortExpression([
+                    "SUM(CASE WHEN ho.overall_status = 'red' THEN 1 ELSE 0 END)",
+                    "SUM(CASE WHEN ho.overall_status = 'yellow' THEN 1 ELSE 0 END)",
+                    "SUM(CASE WHEN ho.overall_status = 'gray' THEN 1 ELSE 0 END)",
+                    "SUM(CASE WHEN ho.overall_status = 'green' THEN 1 ELSE 0 END)"
+                ])
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('cpu', $this->translate('CPU'), [
                 'used_mhz'  => 'SUM(hqs.overall_cpu_usage)',
-                'total_mhz' => 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)',
-            ])->setRenderer(function ($row) {
-                $bar = new CpuUsage($row->used_mhz, $row->total_mhz);
-                if ($this->hasChosenColumn('overall_cpu_usage') || $this->hasChosenColumn('hardware_cpu_mhz')) {
-                    $bar->showLabels(false);
-                }
-                return $bar;
-            })->setSortExpression(
-                '(overall_cpu_usage / total_mhz)'
-            )->setDefaultSortDirection('DESC'),
-            $this->createColumn('overall_cpu_usage', $this->translate('Used'), 'SUM(hqs.overall_cpu_usage)')
+                'total_mhz' => 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)'
+            ])
                 ->setRenderer(function ($row) {
-                    return Format::mhz($row->overall_cpu_usage);
-                })->setDefaultSortDirection('DESC'),
+                    $bar = new CpuUsage($row->used_mhz, $row->total_mhz);
+                    if ($this->hasChosenColumn('overall_cpu_usage') || $this->hasChosenColumn('hardware_cpu_mhz')) {
+                        $bar->showLabels(false);
+                    }
+
+                    return $bar;
+                })
+                ->setSortExpression('(overall_cpu_usage / total_mhz)')
+                ->setDefaultSortDirection('DESC'),
+
+            $this->createColumn('overall_cpu_usage', $this->translate('Used'), 'SUM(hqs.overall_cpu_usage)')
+                ->setRenderer(fn($row) => Format::mhz($row->overall_cpu_usage))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn(
                 'hardware_cpu_mhz',
                 $this->translate('Capacity'),
                 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)'
-            )->setRenderer(function ($row) {
-                return Format::mhz($row->hardware_cpu_mhz);
-            })->setDefaultSortDirection('DESC'),
+            )
+                ->setRenderer(fn($row) => Format::mhz($row->hardware_cpu_mhz))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('hardware_cpu_cores', $this->translate('Cores'), 'SUM(h.hardware_cpu_cores)')
-                ->setRenderer(function ($row) {
-                    return Html::tag('td', ['class' => 'text-right'], $row->hardware_cpu_cores);
-                })
+                ->setRenderer(fn($row) => Html::tag('td', ['class' => 'text-right'], $row->hardware_cpu_cores))
                 ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('memory', $this->translate('Memory'), [
                 'memory_used_mb'  => 'SUM(hqs.overall_memory_usage_mb)',
-                'memory_total_mb' => 'SUM(h.hardware_memory_size_mb)',
-            ])->setRenderer(function ($row) {
-                $bar = new MemoryUsage($row->memory_used_mb, $row->memory_total_mb);
-                if ($this->hasChosenColumn('overall_memory_usage') || $this->hasChosenColumn('hardware_memorymb')) {
-                    $bar->showLabels(false);
-                }
-                return $bar;
-            })->setSortExpression(
-                '(memory_used_mb / memory_total_mb)'
-            )->setDefaultSortDirection('DESC'),
-            $this->createColumn('overall_memory_usage', $this->translate('Used'), 'SUM(hqs.overall_memory_usage_mb)')
+                'memory_total_mb' => 'SUM(h.hardware_memory_size_mb)'
+            ])
                 ->setRenderer(function ($row) {
-                    return Format::mBytes($row->overall_memory_usage);
-                })->setDefaultSortDirection('DESC'),
+                    $bar = new MemoryUsage($row->memory_used_mb, $row->memory_total_mb);
+                    if ($this->hasChosenColumn('overall_memory_usage') || $this->hasChosenColumn('hardware_memorymb')) {
+                        $bar->showLabels(false);
+                    }
+
+                    return $bar;
+                })
+                ->setSortExpression('(memory_used_mb / memory_total_mb)')
+                ->setDefaultSortDirection('DESC'),
+
+            $this->createColumn('overall_memory_usage', $this->translate('Used'), 'SUM(hqs.overall_memory_usage_mb)')
+                ->setRenderer(fn($row) => Format::mBytes($row->overall_memory_usage))
+                ->setDefaultSortDirection('DESC'),
+
             $this->createColumn('hardware_memory_mb', $this->translate('Capacity'))
-                ->setRenderer(function ($row) {
-                    return Format::mBytes($row->hardware_memory_mb);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::mBytes($row->hardware_memory_mb))
+                ->setDefaultSortDirection('DESC')
         ]);
     }
 
-    protected function addDatastoreColumns()
+    protected function addDatastoreColumns(): void
     {
         $this->addAvailableColumns([
             $this->createColumn('datastore_usage', $this->translate('Storage'), [
                 'ds_capacity'   => 'ds.ds_capacity',
-                'ds_free_space' => 'ds.ds_free_space',
-            ])->setRenderer(function ($row) {
-                return new MemoryUsage(
+                'ds_free_space' => 'ds.ds_free_space'
+            ])
+                ->setRenderer(fn($row) => new MemoryUsage(
                     ($row->ds_capacity - $row->ds_free_space) / 1000000,
                     $row->ds_capacity / 1000000
-                );
-            })->setSortExpression('(ds.ds_capacity - ds.ds_free_space) / ds.ds_capacity'),
+                ))
+                ->setSortExpression('(ds.ds_capacity - ds.ds_free_space) / ds.ds_capacity')
         ]);
     }
 
-    protected function addVCenterColumns()
+    protected function addVCenterColumns(): void
     {
         $this->addAvailableColumns([
             $this->createColumn('vcenter_software', $this->translate('Software'), [
-                'software_name' => 'vc.api_name',
-                'software_version' => 'vc.version',
-            ])->setRenderer(function ($row) {
+                'software_name'    => 'vc.api_name',
+                'software_version' => 'vc.version'
+            ])
                 // VMware ESXi -> ESXi
-                return \sprintf(
+                ->setRenderer(fn($row) => sprintf(
                     '%s (%s)',
-                    \preg_replace('/^VMware /', '', $row->software_name),
+                    preg_replace('/^VMware /', '', $row->software_name),
                     $row->software_version
-                );
-            }),
+                ))
         ]);
     }
 
-    protected function renderHostSummaries($row)
+    protected function renderHostSummaries(object $row): ?array
     {
         $params = $this->getFilterParams($row);
 
@@ -248,9 +255,12 @@ protected function renderHostSummaries($row)
             foreach (['red', 'yellow', 'gray', 'green'] as $state) {
                 $column = "hosts_cnt_overall_$state";
                 if ($row->$column > 0) {
-                    $result[] = Link::create($row->$column, 'vspheredb/hosts', $params + [
-                            'overall_status' => $state
-                        ], ['class' => ['state', $state]]);
+                    $result[] = Link::create(
+                        $row->$column,
+                        'vspheredb/hosts',
+                        $params + ['overall_status' => $state],
+                        ['class' => ['state', $state]]
+                    );
                 }
             }
         }
@@ -258,28 +268,28 @@ protected function renderHostSummaries($row)
         if (empty($result)) {
             return null;
         }
+
         return [
             Html::tag('br'),
-            Html::tag('small', $result),
+            Html::tag('small', $result)
         ];
     }
 
-    protected function getHostCountColumns()
+    protected function getHostCountColumns(): array
     {
         return [
-            'hosts_cnt' => 'COUNT(DISTINCT ho.uuid)',
+            'hosts_cnt'                => 'COUNT(DISTINCT ho.uuid)',
             'hosts_cnt_overall_gray'   => "SUM(CASE WHEN ho.overall_status = 'gray' THEN 1 ELSE 0 END)",
             'hosts_cnt_overall_green'  => "SUM(CASE WHEN ho.overall_status = 'green' THEN 1 ELSE 0 END)",
             'hosts_cnt_overall_yellow' => "SUM(CASE WHEN ho.overall_status = 'yellow' THEN 1 ELSE 0 END)",
-            'hosts_cnt_overall_red'    => "SUM(CASE WHEN ho.overall_status = 'red' THEN 1 ELSE 0 END)",
+            'hosts_cnt_overall_red'    => "SUM(CASE WHEN ho.overall_status = 'red' THEN 1 ELSE 0 END)"
         ];
     }
 
-    protected function prepareHostsQuery()
+    protected function prepareHostsQuery(): Select|Zend_Db_Select
     {
-        return $this->db()->select()->from(
-            ['h' => 'host_system'],
-            [
+        return $this->db()->select()
+            ->from(['h' => 'host_system'], [
                 'vcenter_uuid'             => 'h.vcenter_uuid',
                 'hosts_cnt'                => 'COUNT(DISTINCT h.uuid)',
                 'hosts_cnt_overall_gray'   => "SUM(CASE WHEN ho.overall_status = 'gray' THEN 1 ELSE 0 END)",
@@ -296,64 +306,48 @@ protected function prepareHostsQuery()
                 'memory_used_mb'           => 'SUM(hqs.overall_memory_usage_mb)',
                 'memory_total_mb'          => 'SUM(h.hardware_memory_size_mb)',
                 'overall_memory_usage'     => 'SUM(hqs.overall_memory_usage_mb)',
-                'hardware_memory_mb'       => 'SUM(h.hardware_memory_size_mb)',
-            ]
-        )->join(
-            ['ho' => 'object'],
-            'ho.uuid = h.uuid',
-            []
-        )->join(
-            ['hqs' => 'host_quick_stats'],
-            'hqs.uuid = h.uuid',
-            []
-        )
+                'hardware_memory_mb'       => 'SUM(h.hardware_memory_size_mb)'
+            ])
+            ->join(['ho' => 'object'], 'ho.uuid = h.uuid', [])
+            ->join(['hqs' => 'host_quick_stats'], 'hqs.uuid = h.uuid', [])
             ->group('h.vcenter_uuid');
     }
 
-    protected function prepareDatastoreQuery()
+    protected function prepareDatastoreQuery(): Select|Zend_Db_Select
     {
-        return $this->db()->select()->from(
-            // TODO: Join object?
-            ['ds' => 'datastore'],
-            [
+        // TODO: Join object?
+        return $this->db()->select()
+            ->from(['ds' => 'datastore'], [
                 'vcenter_uuid'   => 'ds.vcenter_uuid',
                 'ds_capacity'    => 'SUM(ds.capacity)',
                 'ds_free_space'  => 'SUM(ds.free_space)',
-                'ds_uncommitted' => 'SUM(ds.uncommitted)',
-            ]
-        )->group('ds.vcenter_uuid');
+                'ds_uncommitted' => 'SUM(ds.uncommitted)'
+            ])
+            ->group('ds.vcenter_uuid');
     }
 
-    protected function prepareQuery()
+    protected function prepareQuery(): Select|Zend_Db_Select
     {
         $vCenterColumns = [
             'uuid' => 'vc.instance_uuid',
             'vcenter_id' => 'vc.id',
             'name' => 'vc.name',
             'software_name' => 'vc.api_name',
-            'software_version' => 'vc.version',
+            'software_version' => 'vc.version'
         ];
 
-        return $this->db()->select()->from(
-            ['vc' => 'vcenter'],
-            $vCenterColumns + ['h.*', 'ds.*']
-        )->joinLeft(
-            ['ds' => $this->prepareDatastoreQuery()],
-            'vc.instance_uuid = ds.vcenter_uuid',
-            []
-        )->joinLeft(
-            ['h' => $this->prepareHostsQuery()],
-            'vc.instance_uuid = h.vcenter_uuid',
-            []
-        );
+        return $this->db()->select()
+            ->from(['vc' => 'vcenter'], $vCenterColumns + ['h.*', 'ds.*'])
+            ->joinLeft(['ds' => $this->prepareDatastoreQuery()], 'vc.instance_uuid = ds.vcenter_uuid', [])
+            ->joinLeft(['h' => $this->prepareHostsQuery()], 'vc.instance_uuid = h.vcenter_uuid', []);
     }
 
-    protected function getGroupingTitle()
+    protected function getGroupingTitle(): string
     {
         return $this->translate('VCenter');
     }
 
-    protected function getFilterParams($row)
+    protected function getFilterParams($row): array
     {
         return ['vcenter' => Util::niceUuid($row->uuid)];
     }
diff --git a/library/Vspheredb/Web/Table/Objects/VmsGuestDiskUsageTable.php b/library/Vspheredb/Web/Table/Objects/VmsGuestDiskUsageTable.php
index 7179264b..f278a26f 100644
--- a/library/Vspheredb/Web/Table/Objects/VmsGuestDiskUsageTable.php
+++ b/library/Vspheredb/Web/Table/Objects/VmsGuestDiskUsageTable.php
@@ -3,126 +3,113 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
 use gipfl\IcingaWeb2\Img;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Format;
 use Icinga\Module\Vspheredb\Web\Widget\SimpleUsageBar;
 use ipl\Html\Html;
+use Zend_Db_Select;
 
 class VmsGuestDiskUsageTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/vm';
+    protected ?string $baseUrl = 'vspheredb/vm';
 
     protected $searchColumns = [
         'object_name',
-        'disk_path',
+        'disk_path'
     ];
 
-    protected $withHistory = false;
+    protected bool $withHistory = false;
 
-    public function filterHost($uuid)
+    public function filterHost(string $uuid): static
     {
         $this->getQuery()->where('vc.runtime_host_uuid = ?', $uuid);
 
         return $this;
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createObjectNameColumn(),
+
             $this->createColumn('disk_path', $this->translate('Disk Path'), 'vdu.disk_path'),
+
             $this->createColumn('free_space', $this->translate('Free Space'), 'vdu.free_space')
-                ->setRenderer(function ($row) {
-                    return Format::bytes($row->free_space);
-                }),
+                ->setRenderer(fn($row) => Format::bytes($row->free_space)),
+
             $this->createColumn('capacity', $this->translate('Capacity'), 'vdu.capacity')
-                ->setRenderer(function ($row) {
-                    return Format::bytes($row->capacity);
-                }),
+                ->setRenderer(fn($row) => Format::bytes($row->capacity)),
+
             $this->createColumn('usage', $this->translate('Usage'), [
                 'free_space' => 'vdu.free_space',
-                'capacity'   => 'vdu.capacity',
-            ])->setRenderer(function ($row) {
-                $title = sprintf(
+                'capacity'   => 'vdu.capacity'
+            ])
+                ->setRenderer(fn($row) => new SimpleUsageBar($row->capacity - $row->free_space, $row->capacity, sprintf(
                     '%s free out of %s (%.2F %%)',
                     $row->free_space,
                     $row->capacity,
                     $row->free_space / $row->capacity * 100
-                );
-
-                return new SimpleUsageBar($row->capacity - $row->free_space, $row->capacity, $title);
-            })->setSortExpression(
-                '1 - (vdu.free_space / vdu.capacity)'
-            )->setDefaultSortDirection('DESC'),
+                )))
+                ->setSortExpression('1 - (vdu.free_space / vdu.capacity)')
+                ->setDefaultSortDirection('DESC')
         ]);
 
         if ($this->withHistory) {
             $this->addAvailableColumn(
-                $this->createColumn('history', $this->translate('History'), [
-                    'object_name' => 'o.object_name',
-                ])->setRenderer(function ($row) {
-                    $ciName = str_replace(' ', '_', $row->object_name);
-                    $path = str_replace('/', '_', $row->disk_path);
-                    $path = str_replace(' ', '_', $path);
-                    $ci = $ciName . ':' . $path;
-                    $now = time();
-                    $end = floor($now / 60) * 60;
-                    $offset = 3600 * 24 * 96;
-                    $duration = 3600 * 12 * 4;
-                    $start = $end - $offset;
-                    $end = $start + $duration;
-
-                    return Html::tag(
-                        'div',
-                        ['class' => 'vm-disk-usage-history'],
-                        Html::tag(
+                $this->createColumn('history', $this->translate('History'), ['object_name' => 'o.object_name'])
+                    ->setRenderer(function ($row) {
+                        $ciName = str_replace(' ', '_', $row->object_name);
+                        $path = str_replace('/', '_', $row->disk_path);
+                        $path = str_replace(' ', '_', $path);
+                        $ci = $ciName . ':' . $path;
+                        $now = time();
+                        $end = floor($now / 60) * 60;
+                        $offset = 3600 * 24 * 96;
+                        $duration = 3600 * 12 * 4;
+                        $start = $end - $offset;
+                        $end = $start + $duration;
+
+                        return Html::tag(
                             'div',
-                            ['class' => 'inline-perf-container'],
-                            Img::create(
-                                'rrd/img',
-                                [
-                                    'file'     => $ci . '.rrd',
-                                    'rnd'      => time(),
-                                    'height'   => 24 * 6,
-                                    'width'    => 80 * 6,
-                                    'start'    => $start,
-                                    'end'      => $end,
-                                    'template' => 'vm_disk',
-                                ],
-                                ['class' => 'inline-perf-small']
+                            ['class' => 'vm-disk-usage-history'],
+                            Html::tag(
+                                'div',
+                                ['class' => 'inline-perf-container'],
+                                Img::create(
+                                    'rrd/img',
+                                    [
+                                        'file'     => $ci . '.rrd',
+                                        'rnd'      => time(),
+                                        'height'   => 24 * 6,
+                                        'width'    => 80 * 6,
+                                        'start'    => $start,
+                                        'end'      => $end,
+                                        'template' => 'vm_disk'
+                                    ],
+                                    ['class' => 'inline-perf-small']
+                                )
                             )
-                        )
-                    );
-                })
+                        );
+                    })
             );
         }
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $columns = $this->getRequiredDbColumns();
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $columns
-        )->join(
-            ['vc' => 'virtual_machine'],
-            'o.uuid = vc.uuid',
-            []
-        )->join(
-            ['vdu' => 'vm_disk_usage'],
-            'vc.uuid = vdu.vm_uuid',
-            []
-        );
-
-        return $query;
+        return $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->join(['vc' => 'virtual_machine'], 'o.uuid = vc.uuid', [])
+            ->join(['vdu' => 'vm_disk_usage'], 'vc.uuid = vdu.vm_uuid', []);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'object_name',
             'disk_path',
             'capacity',
-            'usage',
+            'usage'
         ];
     }
 }
diff --git a/library/Vspheredb/Web/Table/Objects/VmsSnapshotsTable.php b/library/Vspheredb/Web/Table/Objects/VmsSnapshotsTable.php
index 13bce23b..8b4d296c 100644
--- a/library/Vspheredb/Web/Table/Objects/VmsSnapshotsTable.php
+++ b/library/Vspheredb/Web/Table/Objects/VmsSnapshotsTable.php
@@ -3,83 +3,69 @@
 namespace Icinga\Module\Vspheredb\Web\Table\Objects;
 
 use gipfl\IcingaWeb2\Link;
+use gipfl\ZfDb\Select;
 use Icinga\Date\DateFormatter;
 use Icinga\Module\Vspheredb\Util;
+use Zend_Db_Select;
 
 class VmsSnapshotsTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/vm';
+    protected ?string $baseUrl = 'vspheredb/vm';
 
     protected $searchColumns = [
         'object_name',
-        'guest_host_name',
+        'guest_host_name'
     ];
 
-    public function filterHost($uuid)
+    public function filterHost(string $uuid): static
     {
         $this->getQuery()->where('vc.runtime_host_uuid = ?', $uuid);
 
         return $this;
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             $this->createColumn('guest_name', $this->translate('Guest hostname'), [
                 'object_name'     => 'o.object_name',
                 'uuid'            => 'vm.uuid',
-                'guest_host_name' => 'vm.guest_host_name',
-            ])->setRenderer(function ($row) {
-                if ($row->guest_host_name === null || $row->guest_host_name === $row->object_name) {
-                    $name = $row->object_name;
-                } else {
-                    $name = sprintf('%s (%s)', $row->object_name, $row->guest_host_name);
-                }
-
-                return Link::create(
-                    $name,
+                'guest_host_name' => 'vm.guest_host_name'
+            ])
+                ->setRenderer(fn($row) => Link::create(
+                    $row->guest_host_name === null || $row->guest_host_name === $row->object_name
+                        ? $row->object_name
+                        : sprintf('%s (%s)', $row->object_name, $row->guest_host_name),
                     $this->baseUrl,
                     Util::uuidParams($row->uuid)
-                );
-            }),
+                )),
+
             $this->createColumn('cnt', $this->translate('Snapshots'), 'COUNT(*)'),
+
             $this->createColumn('ts_oldest', $this->translate('Oldest'), 'MIN(vms.ts_create)')
-                ->setRenderer(function ($row) {
-                    return DateFormatter::formatDate($row->ts_oldest / 1000);
-                }),
+                ->setRenderer(fn($row) => DateFormatter::formatDate($row->ts_oldest / 1000)),
+
             $this->createColumn('ts_newest', $this->translate('Newest'), 'MAX(vms.ts_create)')
-                ->setRenderer(function ($row) {
-                    return DateFormatter::formatDate($row->ts_newest / 1000);
-                })
+                ->setRenderer(fn($row) => DateFormatter::formatDate($row->ts_newest / 1000))
         ]);
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $columns = $this->getRequiredDbColumns();
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $columns
-        )->join(
-            ['vm' => 'virtual_machine'],
-            'o.uuid = vm.uuid',
-            []
-        )->join(
-            ['vms' => 'vm_snapshot'],
-            'vms.vm_uuid = vm.uuid',
-            []
-        )->group('vm.uuid');
-
-        return $query;
+        return $this->db()->select()
+            ->from(['o' => 'object'], $this->getRequiredDbColumns())
+            ->join(['vm' => 'virtual_machine'], 'o.uuid = vm.uuid', [])
+            ->join(['vms' => 'vm_snapshot'], 'vms.vm_uuid = vm.uuid', [])
+            ->group('vm.uuid');
     }
 
-    public function XXgetDefaultColumnNames()
+    public function XXgetDefaultColumnNames(): array
     {
         return [
             'object_name',
             'disk_path',
             'free_space',
-            'capacity',
+            'capacity'
         ];
     }
 }
diff --git a/library/Vspheredb/Web/Table/Objects/VmsTable.php b/library/Vspheredb/Web/Table/Objects/VmsTable.php
index cb35ebad..36da262c 100644
--- a/library/Vspheredb/Web/Table/Objects/VmsTable.php
+++ b/library/Vspheredb/Web/Table/Objects/VmsTable.php
@@ -4,36 +4,39 @@
 
 use gipfl\IcingaWeb2\Img;
 use gipfl\IcingaWeb2\Link;
+use gipfl\ZfDb\Select;
 use Icinga\Date\DateFormatter;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
+use Icinga\Module\Vspheredb\Format;
+use Icinga\Module\Vspheredb\Web\Table\SimpleColumn;
 use Icinga\Module\Vspheredb\Web\Widget\DelayedPerfdataRenderer;
 use Icinga\Module\Vspheredb\Web\Widget\GuestToolsStatusRenderer;
 use Icinga\Module\Vspheredb\Web\Widget\MemoryUsage;
 use Icinga\Module\Vspheredb\Web\Widget\PowerStateRenderer;
 use Icinga\Module\Vspheredb\Web\Widget\Renderer\GuestToolsVersionRenderer;
-use Icinga\Module\Vspheredb\Format;
 use ipl\Html\Html;
 use Ramsey\Uuid\Uuid;
+use Zend_Db_Select;
 
 class VmsTable extends ObjectsTable
 {
-    protected $baseUrl = 'vspheredb/vm';
+    protected ?string $baseUrl = 'vspheredb/vm';
 
     protected $searchColumns = [
         'object_name',
         'guest_host_name',
         'guest_ip_address',
-        'moref',
+        'moref'
     ];
 
-    public function filterHost($uuid)
+    public function filterHost(string $uuid): static
     {
         $this->getQuery()->where('vm.runtime_host_uuid = ?', $uuid);
 
         return $this;
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
         $columns = $this->getRequiredDbColumns();
         $wantsHosts = false;
@@ -42,97 +45,74 @@ public function prepareQuery()
         $wantsDisks = false;
         $wantsDataStores = false;
         foreach ($columns as $column) {
-            if (substr($column, 0, 2) === 'h.') {
+            if (str_starts_with($column, 'h.')) {
                 $wantsHosts = true;
             }
-            if (substr($column, 0, 4) === 'vqs.') {
+            if (str_starts_with($column, 'vqs.')) {
                 $wantsStats = true;
             }
-            if (substr($column, 0, 3) === 'vc.') {
+            if (str_starts_with($column, 'vc.')) {
                 $wantsVCenter = true;
             }
-            if (substr($column, 0, 4) === 'vmd.') {
+            if (str_starts_with($column, 'vmd.')) {
                 $wantsDisks = true;
             }
-            if (substr($column, 0, 4) === 'vdu.') {
+            if (str_starts_with($column, 'vdu.')) {
                 $wantsDataStores = true;
             }
         }
 
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            $columns
-        )->join(
-            ['vm' => 'virtual_machine'],
-            'o.uuid = vm.uuid',
-            []
-        );
+        $query = $this->db()->select()
+            ->from(['o' => 'object'], $columns)
+            ->join(['vm' => 'virtual_machine'], 'o.uuid = vm.uuid', []);
 
         if ($wantsStats) {
-            $query->join(
-                ['vqs' => 'vm_quick_stats'],
-                'vqs.uuid = vm.uuid',
-                []
-            );
+            $query->join(['vqs' => 'vm_quick_stats'], 'vqs.uuid = vm.uuid', []);
         }
 
         if ($wantsVCenter) {
-            $query->join(
-                ['vc' => 'vcenter'],
-                'vc.instance_uuid = vm.vcenter_uuid',
-                []
-            );
+            $query->join(['vc' => 'vcenter'], 'vc.instance_uuid = vm.vcenter_uuid', []);
         }
 
         if ($wantsHosts) {
-            $query->joinLeft(
-                ['h' => 'host_system'],
-                'vm.runtime_host_uuid = h.uuid',
-                []
-            );
+            $query->joinLeft(['h' => 'host_system'], 'vm.runtime_host_uuid = h.uuid', []);
         }
         if ($wantsDataStores) {
-            $sub = $this->db()->select()->from('vm_datastore_usage', [
-                'vm_uuid' => 'vm_uuid',
-                'datastore_capacity' => 'SUM(committed + uncommitted)',
-                'datastore_usage' => 'SUM(committed)',
-            ])->group('vm_uuid');
+            $sub = $this->db()->select()
+                ->from('vm_datastore_usage', [
+                    'vm_uuid'            => 'vm_uuid',
+                    'datastore_capacity' => 'SUM(committed + uncommitted)',
+                    'datastore_usage'    => 'SUM(committed)'
+                ])
+                ->group('vm_uuid');
+
             $query->joinLeft(['vdu' => $sub], 'vdu.vm_uuid = o.uuid', []);
         }
         if ($wantsDisks) {
-            $sub = $this->db()->select()->from('vm_disk', [
-                'vm_uuid' => 'vm_uuid',
-                'disk_capacity' => 'SUM(capacity)',
-            ])->group('vm_uuid');
-            $query->joinLeft(['vmd' => $sub], 'vmd.vm_uuid = o.uuid', []);
-        }
+            $sub = $this->db()->select()
+                ->from('vm_disk', ['vm_uuid' => 'vm_uuid', 'disk_capacity' => 'SUM(capacity)'])
+                ->group('vm_uuid');
 
-        if ($this->parentUuids) {
-            $query->where('o.parent_uuid IN (?)', $this->parentUuids);
-        }
-        if ($this->filterVCenter) {
-            $query->where('o.vcenter_uuid = ?', $this->filterVCenter->getUuid());
+            $query->joinLeft(['vmd' => $sub], 'vmd.vm_uuid = o.uuid', []);
         }
 
         return $query;
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $powerStateRenderer = new PowerStateRenderer();
         $guestToolsStatusRenderer = new GuestToolsStatusRenderer();
         $guestToolsVersionRenderer = new GuestToolsVersionRenderer();
-        $memoryRenderer = function ($row) {
-            return new MemoryUsage(
-                $row->guest_memory_usage_mb,
-                $row->hardware_memorymb,
-                $row->host_memory_usage_mb
-            );
-        };
+        $memoryRenderer = fn($row) => new MemoryUsage(
+            $row->guest_memory_usage_mb,
+            $row->hardware_memorymb,
+            $row->host_memory_usage_mb
+        );
         $memoryColumns = [
             'guest_memory_usage_mb' => 'vqs.guest_memory_usage_mb',
             'host_memory_usage_mb'  => 'vqs.host_memory_usage_mb',
-            'hardware_memorymb'     => 'vm.hardware_memorymb',
+            'hardware_memorymb'     => 'vm.hardware_memorymb'
         ];
         $this->addAvailableColumns([
             $this->createColumn('runtime_power_state', $this->translate('Power'), 'vm.runtime_power_state')
@@ -142,25 +122,20 @@ protected function initialize()
 
             $this->createObjectNameColumn(),
 
-            $this->createColumn(
-                'guest_tools_status',
-                $this->translate('Guest Tools'),
-                'vm.guest_tools_status'
-            )->setRenderer($guestToolsStatusRenderer)->setSortExpression('vm.guest_tools_status'),
-
-            $this->createColumn(
-                'guest_tools_version',
-                $this->translate('Tools Version'),
-                'vm.guest_tools_version'
-            )
-            ->setRenderer($guestToolsVersionRenderer)
-            ->setSortExpression(
-                "CAST("
-                . "CASE WHEN guest_tools_version = '2147483647' THEN '1' ELSE guest_tools_version END"
-                . " AS SIGNED INTEGER)"
-            ),
+            $this->createColumn('guest_tools_status', $this->translate('Guest Tools'), 'vm.guest_tools_status')
+                ->setRenderer($guestToolsStatusRenderer)
+                ->setSortExpression('vm.guest_tools_status'),
+
+            $this->createColumn('guest_tools_version', $this->translate('Tools Version'), 'vm.guest_tools_version')
+                ->setRenderer($guestToolsVersionRenderer)
+                ->setSortExpression(
+                    "CAST("
+                    . "CASE WHEN guest_tools_version = '2147483647' THEN '1' ELSE guest_tools_version END"
+                    . " AS SIGNED INTEGER)"
+                ),
 
             $this->createColumn('host_name', $this->translate('Host'), 'h.host_name'),
+
             $this->createColumn('vcenter_name', $this->translate('vCenter / ESXi'), 'vc.name'),
 
             $this->createColumn('guest_ip_address', $this->translate('Guest IP'), 'vm.guest_ip_address'),
@@ -169,30 +144,25 @@ protected function initialize()
                 ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('cpu_usage', $this->translate('CPU Usage'), 'vqs.overall_cpu_usage')
-                ->setRenderer(function ($row) {
-                    return Format::mhz($row->cpu_usage);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::mhz($row->cpu_usage))
+                ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('hardware_memorymb', $this->translate('Memory'), 'vm.hardware_memorymb')
-                ->setRenderer(function ($row) {
-                    return Format::mBytes($row->hardware_memorymb);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::mBytes($row->hardware_memorymb))
+                ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('guest_memory_usage_mb', $this->translate('Active Memory'), 'vqs.guest_memory_usage_mb')
-                ->setRenderer(function ($row) {
-                    return Format::mBytes($row->guest_memory_usage_mb);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::mBytes($row->guest_memory_usage_mb))
+                ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('host_memory_usage_mb', $this->translate('Host Memory'), 'vqs.host_memory_usage_mb')
-                ->setRenderer(function ($row) {
-                    return Format::mBytes($row->host_memory_usage_mb);
-                })->setSortExpression('vqs.host_memory_usage_mb')
+                ->setRenderer(fn($row) => Format::mBytes($row->host_memory_usage_mb))
+                ->setSortExpression('vqs.host_memory_usage_mb')
                 ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('ballooned_memory_mb', $this->translate('Balloon'), 'vqs.ballooned_memory_mb')
-                ->setRenderer(function ($row) {
-                    return Format::mBytes($row->ballooned_memory_mb);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::mBytes($row->ballooned_memory_mb))
+                ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('memory_usage', $this->translate('Memory Usage'), $memoryColumns)
                 ->setRenderer($memoryRenderer)
@@ -200,33 +170,23 @@ protected function initialize()
                 ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('disk_capacity', $this->translate('Disks'), 'vmd.disk_capacity')
-                ->setRenderer(function ($row) {
-                    return Format::bytes($row->disk_capacity ?: 0);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::bytes($row->disk_capacity ?: 0))
+                ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('datastore_capacity', $this->translate('Datastore'), 'vdu.datastore_capacity')
-                ->setRenderer(function ($row) {
-                    return Format::bytes($row->datastore_capacity ?: 0);
-                })->setDefaultSortDirection('DESC'),
+                ->setRenderer(fn($row) => Format::bytes($row->datastore_capacity ?: 0))
+                ->setDefaultSortDirection('DESC'),
 
             $this->createColumn('datastore_usage', $this->translate('DS Usage'), 'vdu.datastore_usage')
-                ->setRenderer(function ($row) {
-                    return Format::bytes($row->datastore_usage ?: 0);
-                })->setDefaultSortDirection('DESC'),
-
-            $this->createColumn('uptime', $this->translate('Uptime'), [
-                'uptime' => 'vqs.uptime',
-            ])->setRenderer(function ($row) {
-                if ($row->uptime === null) {
-                    return null;
-                }
+                ->setRenderer(fn($row) => Format::bytes($row->datastore_usage ?: 0))
+                ->setDefaultSortDirection('DESC'),
 
-                return DateFormatter::formatDuration($row->uptime);
-            }),
+            $this->createColumn('uptime', $this->translate('Uptime'), ['uptime' => 'vqs.uptime'])
+                ->setRenderer(fn($row) => $row->uptime === null ? null : DateFormatter::formatDuration($row->uptime))
             /*
             TODO: Not yet
             $this->createColumn('ifTraffic', $this->translate('NIC Usage'), [
-                'moref' => 'o.moref',
+                'moref' => 'o.moref'
             ])->setRenderer(function ($row) {
                 return $this->renderInterface($row->moref, 4000);
             }),
@@ -236,7 +196,7 @@ protected function initialize()
         // $this->addPerfColumns();
     }
 
-    protected function renderInterface($moref, $hardwareKey)
+    protected function renderInterface(string $moref, string $hardwareKey): Img
     {
         $width = 160;
         $height = 30;
@@ -244,77 +204,74 @@ protected function renderInterface($moref, $hardwareKey)
         $end = floor((time() - $rand) / 300) * 300;
         $start = $end - $rand;
         $params = [
-            'file'     => sprintf('%s/iface%s.rrd', $moref, $hardwareKey),
-            'height'   => $height,
-            'width'    => $width,
-            'rnd'      => floor(time() / 20),
-            'format'   => 'png',
-            'start'    => $start,
-            'end'      => $end,
+            'file'   => sprintf('%s/iface%s.rrd', $moref, $hardwareKey),
+            'height' => $height,
+            'width'  => $width,
+            'rnd'    => floor(time() / 20),
+            'format' => 'png',
+            'start'  => $start,
+            'end'    => $end
         ];
         $attrs = [
             'height' => $height,
-            'width'  => $width,
+            'width'  => $width
             //'align'  => 'right',
             // 'style'  => 'border-bottom: 1px solid rgba(0, 0, 0, 0.3); border-left: 1px solid rgba(0, 0, 0, 0.3);'
         ];
 
-        return Img::create('rrd/img', $params + [
-            'template' => 'vSphereDB-vmIfTraffic',
-        ], $attrs);
+        return Img::create('rrd/img', $params + ['template' => 'vSphereDB-vmIfTraffic'], $attrs);
     }
 
-    protected function addPerfColumns()
+    protected function addPerfColumns(): void
     {
         $perf = new DelayedPerfdataRenderer($this->db());
         $this->addAvailableColumns([
             $perf->getDiskColumn()->setDefaultSortDirection('DESC'),
             $perf->getNetColumn()->setDefaultSortDirection('DESC'),
             $perf->getCurrentNetColumn()->setDefaultSortDirection('DESC'),
-            $perf->getCurrentDiskColumn()->setDefaultSortDirection('DESC'),
+            $perf->getCurrentDiskColumn()->setDefaultSortDirection('DESC')
         ]);
     }
 
-    public function getDefaultColumnNames()
+    public function getDefaultColumnNames(): array
     {
         return [
             'object_name',
             'cpu_usage',
-            'memory_usage',
+            'memory_usage'
         ];
     }
 
-    protected function getDefaultSortColumns()
+    protected function getDefaultSortColumns(): array
     {
         return ['object_name'];
     }
 
-    protected function createObjectNameColumn()
+    protected function createObjectNameColumn(): SimpleColumn
     {
         return $this->createColumn('object_name', $this->translate('Name'), [
             'object_name'         => 'o.object_name',
             'overall_status'      => 'o.overall_status',
             'runtime_power_state' => 'vm.runtime_power_state',
             'template'            => 'vm.template',
-            'uuid'                => 'o.uuid',
-        ])->setRenderer(function ($row) {
-            if (in_array('overall_status', $this->getChosenColumnNames())) {
-                $result = [];
-            } else {
-                $statusRenderer = $this->overallStatusRenderer();
-                $result = [$statusRenderer($row)];
-            }
-            $name = Anonymizer::anonymizeString($row->object_name);
-            if ($row->template === 'y') {
-                $name = [$name, Html::tag('i', ' (' . $this->translate('Template') . ')')];
-            }
-            if ($this->baseUrl === null) {
-                $result[] = $name;
-            } else {
-                $result[] = Link::create($name, $this->baseUrl, ['uuid' => Uuid::fromBytes($row->uuid)->toString()]);
-            }
+            'uuid'                => 'o.uuid'
+        ])
+            ->setRenderer(function ($row) {
+                if (in_array('overall_status', $this->getChosenColumnNames())) {
+                    $result = [];
+                } else {
+                    $statusRenderer = $this->overallStatusRenderer();
+                    $result = [$statusRenderer($row)];
+                }
+                $name = Anonymizer::anonymizeString($row->object_name);
+                if ($row->template === 'y') {
+                    $name = [$name, Html::tag('i', ' (' . $this->translate('Template') . ')')];
+                }
+                $result[] = $this->baseUrl === null
+                    ? $name
+                    : Link::create($name, $this->baseUrl, ['uuid' => Uuid::fromBytes($row->uuid)->toString()]);
 
-            return $result;
-        });
+                return $result;
+            });
     }
 }
diff --git a/library/Vspheredb/Web/Table/PerfDataConsumerTable.php b/library/Vspheredb/Web/Table/PerfDataConsumerTable.php
index 8e367f49..2064f5ac 100644
--- a/library/Vspheredb/Web/Table/PerfDataConsumerTable.php
+++ b/library/Vspheredb/Web/Table/PerfDataConsumerTable.php
@@ -3,43 +3,44 @@
 namespace Icinga\Module\Vspheredb\Web\Table;
 
 use gipfl\IcingaWeb2\Link;
+use gipfl\ZfDb\Select;
 use Ramsey\Uuid\Uuid;
+use Zend_Db_Select;
 
 class PerfDataConsumerTable extends BaseTable
 {
-    protected $keyColumn = 'uuid';
+    protected string $keyColumn = 'uuid';
 
     protected $defaultAttributes = [
         'class' => ['common-table', 'table-row-selectable'],
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
             (new SimpleColumn('name', $this->translate('Name'), [
                 'uuid' => 'pc.uuid',
-                'name' => 'pc.name',
-            ]))->setRenderer(function ($row) {
-                return Link::create($row->name, 'vspheredb/perfdata/consumer', [
-                    'uuid' => Uuid::fromBytes($row->uuid)
-                ], [
-                    'data-base-target' => '_next'
-                ]);
-            }),
+                'name' => 'pc.name'
+            ]))
+                ->setRenderer(fn($row) => Link::create(
+                    $row->name,
+                    'vspheredb/perfdata/consumer',
+                    ['uuid' => Uuid::fromBytes($row->uuid)],
+                    ['data-base-target' => '_next']
+                )),
+
             (new SimpleColumn('implementation', $this->translate('Implementation'), [
-                'implementation' => 'pc.implementation',
-            ]))->setRenderer(function ($row) {
-                return $row->implementation;
-            }),
+                'implementation' => 'pc.implementation'
+            ]))
+                ->setRenderer(fn($row) => $row->implementation)
         ]);
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        return $this->db()->select()->from(
-            ['pc' => 'perfdata_consumer'],
-            $this->getRequiredDbColumns()
-        )->order('name');
+        return $this->db()->select()
+            ->from(['pc' => 'perfdata_consumer'], $this->getRequiredDbColumns())
+            ->order('name');
     }
 }
diff --git a/library/Vspheredb/Web/Table/PerformanceCounterTable.php b/library/Vspheredb/Web/Table/PerformanceCounterTable.php
index de6fe136..f557e4a0 100644
--- a/library/Vspheredb/Web/Table/PerformanceCounterTable.php
+++ b/library/Vspheredb/Web/Table/PerformanceCounterTable.php
@@ -3,12 +3,13 @@
 namespace Icinga\Module\Vspheredb\Web\Table;
 
 use gipfl\IcingaWeb2\Url;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
+use Zend_Db_Select;
 
 class PerformanceCounterTable extends BaseTable
 {
-    /** @var VCenter */
-    protected $vCenter;
+    protected ?VCenter $vCenter;
 
     protected $searchColumns = [
         'counter_key',
@@ -18,9 +19,9 @@ class PerformanceCounterTable extends BaseTable
         'label',
         'summary',
         'stats_type',
-        'rollup_type',
+        'rollup_type'
         // TODO: disabled, Director breaks this right now for security reasons
-        // "(c.group_name || '.' || c.name)",
+        // "(c.group_name || '.' || c.name)"
     ];
 
     public function __construct($db, ?Url $url = null, ?VCenter $vCenter = null)
@@ -29,41 +30,25 @@ public function __construct($db, ?Url $url = null, ?VCenter $vCenter = null)
         parent::__construct($db, $url);
     }
 
-    protected function initialize()
+    protected function initialize(): void
     {
         $this->addAvailableColumns([
-            $this->createColumn('key', $this->translate('Key'), [
-                'group_name',
-                'name'
-            ])->setRenderer(function ($row) {
-                return sprintf(
-                    '%s.%s',
-                    $row->group_name,
-                    $row->name
-                );
-            }),
-            $this->createColumn('name', $this->translate('Name'), [
-                'group_name',
-                'name'
-            ])->setRenderer(function ($row) {
-                return sprintf(
-                    '%s.%s',
-                    $row->label,
-                    $row->summary
-                );
-            }),
+            $this->createColumn('key', $this->translate('Key'), ['group_name', 'name'])
+                ->setRenderer(fn($row) => sprintf('%s.%s', $row->group_name, $row->name)),
+
+            $this->createColumn('name', $this->translate('Name'), ['group_name', 'name'])
+                ->setRenderer(fn($row) => sprintf('%s.%s', $row->label, $row->summary)),
+
             $this->createColumn('unit_name', $this->translate('Unit')),
             $this->createColumn('stats_type', $this->translate('Stats')),
             $this->createColumn('rollup_type', $this->translate('Rollup')),
-            $this->createColumn('counter_key', $this->translate('ID')),
+            $this->createColumn('counter_key', $this->translate('ID'))
         ]);
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['c' => 'performance_counter']
-        );
+        $query = $this->db()->select()->from(['c' => 'performance_counter']);
         // ->order('group_name')->order('name')->order('unit_name');
 
         if ($this->vCenter !== null) {
diff --git a/library/Vspheredb/Web/Table/SimpleColumn.php b/library/Vspheredb/Web/Table/SimpleColumn.php
index 1f46ed6d..ba0f9046 100644
--- a/library/Vspheredb/Web/Table/SimpleColumn.php
+++ b/library/Vspheredb/Web/Table/SimpleColumn.php
@@ -4,7 +4,7 @@
 
 class SimpleColumn extends TableColumn
 {
-    public function __construct($alias, $title = null, $column = null)
+    public function __construct(string $alias, ?string $title = null, string|array|null $column = null)
     {
         $this->setAlias($alias);
         $this->setTitle($title ?: $alias);
diff --git a/library/Vspheredb/Web/Table/TableColumn.php b/library/Vspheredb/Web/Table/TableColumn.php
index d1fc181f..8e33e289 100644
--- a/library/Vspheredb/Web/Table/TableColumn.php
+++ b/library/Vspheredb/Web/Table/TableColumn.php
@@ -2,142 +2,144 @@
 
 namespace Icinga\Module\Vspheredb\Web\Table;
 
+use Closure;
 use ipl\Html\Html;
+use ipl\Html\HtmlDocument;
+use ipl\Html\ValidHtml;
 
 abstract class TableColumn
 {
-    /** @var string */
-    private $alias;
+    private ?string $alias = null;
 
-    /** @var string */
-    private $column;
+    private array|string|null $column = null;
 
-    /** @var string */
-    private $title;
+    private ?string $title = null;
 
-    /** @var callable */
-    private $renderer;
+    private ?Closure $renderer = null;
 
-    /** @var string|null */
-    private $sortExpression;
+    private array|string|null $sortExpression = null;
 
-    /** @var string */
-    private $defaultSortDirection = 'ASC';
+    private string $defaultSortDirection = 'ASC';
 
-    public function getRequiredDbColumns()
+    public function getRequiredDbColumns(): array
     {
         $column = $this->getColumn();
         if (is_array($column)) {
             return $column;
-        } else {
-            return [$this->getAlias() => $column];
         }
+
+        return [$this->getAlias() => $column];
     }
 
-    public function getMainColumnExpression()
+    public function getMainColumnExpression(): array|string|null
     {
         $column = $this->getColumn();
         if (is_array($column)) {
             return array_shift($column);
-        } else {
-            return $column;
         }
+
+        return $column;
     }
 
-    public function setRenderer($callback)
+    public function setRenderer(callable $callback): static
     {
-        $this->renderer = $callback;
+        $this->renderer = $callback(...);
 
         return $this;
     }
 
     /**
-     * @return string
+     * @return ?string
      */
-    public function getAlias()
+    public function getAlias(): ?string
     {
         return $this->alias;
     }
 
     /**
      * @param string $alias
+     *
      * @return $this
      */
-    public function setAlias($alias)
+    public function setAlias(string $alias): static
     {
         $this->alias = $alias;
+
         return $this;
     }
 
     /**
-     * @return string
+     * @return array|string|null
      */
-    public function getColumn()
+    public function getColumn(): array|string|null
     {
         return $this->column;
     }
 
     /**
-     * @param string $column
+     * @param array|string $column
+     *
      * @return TableColumn
      */
-    public function setColumn($column)
+    public function setColumn(array|string $column): static
     {
         $this->column = $column;
         return $this;
     }
 
     /**
-     * @return string
+     * @return ?string
      */
-    public function getTitle()
+    public function getTitle(): ?string
     {
         return $this->title;
     }
 
     /**
      * @param string $title
+     *
      * @return $this
      */
-    public function setTitle($title)
+    public function setTitle(string $title): static
     {
         $this->title = $title;
+
         return $this;
     }
 
-    public function renderRow($row)
+    /**
+     * @param $row
+     *
+     * @return ValidHtml|HtmlDocument|mixed
+     */
+    public function renderRow($row): mixed
     {
-        if ($this->renderer === null) {
-            return Html::wantHtml($row->{$this->getAlias()});
-        } else {
-            $func = $this->renderer;
-
-            return $func($row);
-        }
+        return $this->renderer === null ? Html::wantHtml($row->{$this->getAlias()}) : ($this->renderer)($row);
     }
 
     /**
-     * @return null|string
+     * @return array|string|null
      */
-    public function getSortExpression()
+    public function getSortExpression(): array|string|null
     {
         if (null === $this->sortExpression) {
             $column = $this->getColumn();
             if (is_array($column)) {
                 return current($column);
-            } else {
-                return $column;
             }
-        } else {
-            return $this->sortExpression;
+
+            return $column;
         }
+
+        return $this->sortExpression;
     }
 
     /**
-     * @param null|string|array $sortExpression
+     * @param array|string|null $sortExpression
+     *
      * @return $this
      */
-    public function setSortExpression($sortExpression)
+    public function setSortExpression(array|string|null $sortExpression): static
     {
         $this->sortExpression = $sortExpression;
 
@@ -147,18 +149,20 @@ public function setSortExpression($sortExpression)
     /**
      * @return string
      */
-    public function getDefaultSortDirection()
+    public function getDefaultSortDirection(): string
     {
         return $this->defaultSortDirection;
     }
 
     /**
      * @param string $defaultSortDirection
+     *
      * @return $this
      */
-    public function setDefaultSortDirection($defaultSortDirection)
+    public function setDefaultSortDirection(string $defaultSortDirection): static
     {
         $this->defaultSortDirection = $defaultSortDirection;
+
         return $this;
     }
 }
diff --git a/library/Vspheredb/Web/Table/TableWithParentFilter.php b/library/Vspheredb/Web/Table/TableWithParentFilter.php
index 2b80809b..dae3b226 100644
--- a/library/Vspheredb/Web/Table/TableWithParentFilter.php
+++ b/library/Vspheredb/Web/Table/TableWithParentFilter.php
@@ -4,5 +4,5 @@
 
 interface TableWithParentFilter
 {
-    public function filterParentUuids(array $uuids);
+    public function filterParentUuids(array $uuids): static;
 }
diff --git a/library/Vspheredb/Web/Table/TableWithVCenterFilter.php b/library/Vspheredb/Web/Table/TableWithVCenterFilter.php
index 65acbace..b752c87d 100644
--- a/library/Vspheredb/Web/Table/TableWithVCenterFilter.php
+++ b/library/Vspheredb/Web/Table/TableWithVCenterFilter.php
@@ -6,6 +6,7 @@
 
 interface TableWithVCenterFilter
 {
-    public function filterVCenter(VCenter $vCenter);
-    public function filterVCenterUuids(array $uuids);
+    public function filterVCenter(VCenter $vCenter): static;
+
+    public function filterVCenterUuids(array $uuids): static;
 }
diff --git a/library/Vspheredb/Web/Table/TopPerfTable.php b/library/Vspheredb/Web/Table/TopPerfTable.php
index ea293282..312fa04a 100644
--- a/library/Vspheredb/Web/Table/TopPerfTable.php
+++ b/library/Vspheredb/Web/Table/TopPerfTable.php
@@ -4,47 +4,45 @@
 
 use gipfl\IcingaWeb2\Link;
 use Icinga\Module\Vspheredb\Util;
+use ipl\Html\Attributes;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\Html\Table;
 
 class TopPerfTable extends Table
 {
     protected $defaultAttributes = [
         'class' => 'common-table table-row-selectable',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    public function __construct($title, $rows, $format, $link)
+    public function __construct(string $title, ?array $rows, ?string $format, string $link)
     {
         $this->getHeader()->add(Table::tr([
             Table::th($title),
-            Table::th('5x5min')->addAttributes(['class' => 'sparkline-header']),
-            Table::th('Last 5min')->addAttributes(['class' => 'last-5min-header'])
+            Table::th('5x5min')->addAttributes(Attributes::create(['class' => 'sparkline-header'])),
+            Table::th('Last 5min')->addAttributes(Attributes::create(['class' => 'last-5min-header']))
         ]));
         foreach ($rows as $row) {
             $this->getBody()->add(Table::row([
                 $this->$link($row),
                 $this->makeSparkLine($row),
-                $format ? $this->$format($row->value_last) : $row->value_last,
+                $format ? $this->$format($row->value_last) : $row->value_last
             ]));
         }
     }
 
-    protected function createVmLink($row)
+    protected function createVmLink(object $row): Link
     {
         $name = $row->object_name;
         if (property_exists($row, 'instance') && strlen($row->instance)) {
             $name .= ': ' . $row->instance;
         }
 
-        return Link::create(
-            $name,
-            'vspheredb/vm',
-            Util::uuidParams($row->object_uuid)
-        );
+        return Link::create($name, 'vspheredb/vm', Util::uuidParams($row->object_uuid));
     }
 
-    protected function createTopForParentLink($row)
+    protected function createTopForParentLink(object $row): Link
     {
         return Link::create(
             $row->object_name,
@@ -53,35 +51,33 @@ protected function createTopForParentLink($row)
         );
     }
 
-    protected function formatMicroSeconds($num)
+    protected function formatMicroSeconds(int $num): string
     {
         if ($num > 500) {
             return sprintf('%0.2Fms', $num / 1000);
-        } else {
-            return sprintf('%dµs', $num);
         }
+
+        return sprintf('%dµs', $num);
     }
 
-    protected function formatKiloBytesPerSecond($num)
+    protected function formatKiloBytesPerSecond(int $num): string
     {
         $num *= 8;
-        if ($num > 500000) {
-            return sprintf('%0.2F Gbit/s', $num / 1024 / 1024);
-        } elseif ($num > 500) {
-            return sprintf('%0.2F Mbit/s', $num / 1024);
-        } else {
-            return sprintf('%0.2F Kbit/s', $num);
-        }
+        return match (true) {
+            $num > 500000 => sprintf('%0.2F Gbit/s', $num / 1024 / 1024),
+            $num > 500    => sprintf('%0.2F Mbit/s', $num / 1024),
+            default       => sprintf('%0.2F Kbit/s', $num)
+        };
     }
 
-    protected function makeSparkLine($row)
+    protected function makeSparkLine($row): HtmlElement
     {
         $values = [
             $row->value_minus4,
             $row->value_minus3,
             $row->value_minus2,
             $row->value_minus1,
-            $row->value_last,
+            $row->value_last
         ];
 
         return Html::tag('span', [
diff --git a/library/Vspheredb/Web/Table/UuidLinkHelper.php b/library/Vspheredb/Web/Table/UuidLinkHelper.php
index 1110bb0c..9bb6717f 100644
--- a/library/Vspheredb/Web/Table/UuidLinkHelper.php
+++ b/library/Vspheredb/Web/Table/UuidLinkHelper.php
@@ -8,9 +8,9 @@
 
 trait UuidLinkHelper
 {
-    protected $requiredUuids = [];
+    protected array $requiredUuids = [];
 
-    protected $fetchedUuids;
+    protected ?array $fetchedUuids = null;
 
     /**
      * @param ?string $uuid
@@ -42,32 +42,26 @@ public function linkToUuid(?string $uuid): DeferredText
             );
         });
 
-        return $result->setEscaped(true);
+        return $result->setEscaped();
     }
 
-    protected function getUuidBaseUrl($uuid)
+    protected function getUuidBaseUrl($uuid): ?string
     {
-        $type = $this->getUuidProperty($uuid, 'object_type');
-
-        switch ($type) {
-            case 'HostSystem':
-                return 'vspheredb/host';
-            case 'VirtualMachine':
-                return 'vspheredb/vm';
-            case 'Datastore':
-                return 'vspheredb/datastore';
-            default:
-                return null;
-        }
+        return match ($this->getUuidProperty($uuid, 'object_type')) {
+            'HostSystem'     => 'vspheredb/host',
+            'VirtualMachine' => 'vspheredb/vm',
+            'Datastore'      => 'vspheredb/datastore',
+            default          => null
+        };
     }
 
     /**
      * @param ?string $uuid
-     * @param $property
+     * @param string $property
      *
      * @return string
      */
-    protected function getUuidProperty(?string $uuid, $property): string
+    protected function getUuidProperty(?string $uuid, string $property): string
     {
         if ($uuid === null) {
             return '[NULL]';
@@ -79,21 +73,22 @@ protected function getUuidProperty(?string $uuid, $property): string
 
         if (array_key_exists($uuid, $this->fetchedUuids)) {
             return $this->fetchedUuids[$uuid]->$property;
-        } else {
-            return '[UNKNOWN]' . $uuid;
         }
+
+        return '[UNKNOWN]' . $uuid;
     }
 
-    protected function fetchUuidObjectDetails()
+    protected function fetchUuidObjectDetails(): void
     {
-        if (method_exists($this, 'db')) {
-            /** @var \Zend_Db_Adapter_Abstract $db */
-            $db = $this->db();
-        } else {
+        if (! method_exists($this, 'db')) {
             $this->fetchedUuids = [];
 
             return;
         }
+
+        /** @var Zend_Db_Adapter_Abstract $db */
+        $db = $this->db();
+
         if (empty($this->requiredUuids)) {
             $this->fetchedUuids = [];
 
diff --git a/library/Vspheredb/Web/Table/VmDatastoresTable.php b/library/Vspheredb/Web/Table/VmDatastoresTable.php
index 7f563603..0e04199d 100644
--- a/library/Vspheredb/Web/Table/VmDatastoresTable.php
+++ b/library/Vspheredb/Web/Table/VmDatastoresTable.php
@@ -4,6 +4,7 @@
 
 use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\DbObject\Datastore;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
@@ -12,23 +13,20 @@
 use Icinga\Module\Vspheredb\Web\Widget\OverallStatusRenderer;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
 use Icinga\Util\Format;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class VmDatastoresTable extends ZfQueryBasedTable
 {
-    protected $searchColumns = [
-        'object_name',
-    ];
+    protected $searchColumns = ['object_name'];
 
     protected $parentIds;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    /** @var string */
-    protected $uuid;
+    protected ?string $uuid = null;
 
-    /** @var OverallStatusRenderer */
-    protected $renderStatus;
+    protected OverallStatusRenderer $renderStatus;
 
     public function __construct(VirtualMachine $vm)
     {
@@ -39,7 +37,7 @@ public function __construct(VirtualMachine $vm)
         $this->renderStatus = new OverallStatusRenderer();
     }
 
-    protected function setVm(VirtualMachine $vm)
+    protected function setVm(VirtualMachine $vm): static
     {
         $this->vm = $vm;
         $this->uuid = $vm->get('uuid');
@@ -47,72 +45,62 @@ protected function setVm(VirtualMachine $vm)
         return $this;
     }
 
-    public function getColumnsToBeRendered()
+    public function getColumnsToBeRendered(): array
     {
         return [
             $this->translate('Status'),
             $this->translate('Datastore'),
             $this->translate('Size'),
             $this->translate('Usage'),
-            $this->translate('On Datastore'),
+            $this->translate('On Datastore')
         ];
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $size = $row->committed + $row->uncommitted;
         $caption = Link::create(
             $row->object_name,
             'vspheredb/datastore',
             Util::uuidParams($row->uuid),
-            ['title' => sprintf(
-                $this->translate('Datastore: %s'),
-                $row->object_name
-            )]
+            ['title' => sprintf($this->translate('Datastore: %s'), $row->object_name)]
         );
 
         /** @var Db $connection */
         $connection = $this->connection();
         $datastore = Datastore::load($row->uuid, $connection);
-        $usage = new DatastoreUsage($datastore);
-        $usage->setBaseUrl('vspheredb/datastore');
-        $usage->setCapacity($size);
+        $usage = (new DatastoreUsage($datastore))
+            ->setBaseUrl('vspheredb/datastore')
+            ->setCapacity($size)
+            ->addDiskFromDbRow($row);
         $usage->getAttributes()->add('class', 'compact');
-        $usage->addDiskFromDbRow($row);
-        $dsUsage = new DatastoreUsage($datastore);
-        $dsUsage->setBaseUrl('vspheredb/datastore');
+        $dsUsage = (new DatastoreUsage($datastore))
+            ->setBaseUrl('vspheredb/datastore')
+            ->addDiskFromDbRow($row);
         $dsUsage->getAttributes()->add('class', 'compact');
-        $dsUsage->addDiskFromDbRow($row);
 
         $renderStatus = $this->renderStatus;
-        $tr = $this::tr([
+
+        return $this::tr([
             $this::td($renderStatus($row->overall_status)),
             $this::td($caption, ['class' => 'vm-datastore-caption']),
             $this::td(Format::bytes($size), ['class' => 'vm-datastore-size']),
             $this::td($usage, ['class' => 'vm-datastore-usage']),
-            $this::td($dsUsage, ['class' => 'vm-datastore-on-datastore']),
+            $this::td($dsUsage, ['class' => 'vm-datastore-on-datastore'])
         ]);
-
-        return $tr;
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            [
+        return $this->db()->select()
+            ->from(['o' => 'object'], [
                 'uuid'           => 'o.uuid',
                 'overall_status' => 'o.overall_status',
                 'object_name'    => 'o.object_name',
                 'committed'      => 'vdu.committed',
-                'uncommitted'    => 'vdu.uncommitted',
-            ]
-        )->join(
-            ['vdu' => 'vm_datastore_usage'],
-            'vdu.datastore_uuid = o.uuid',
-            []
-        )->where('vdu.vm_uuid = ?', $this->uuid)->order('object_name ASC');
-
-        return $query;
+                'uncommitted'    => 'vdu.uncommitted'
+            ])
+            ->join(['vdu' => 'vm_datastore_usage'], 'vdu.datastore_uuid = o.uuid', [])
+            ->where('vdu.vm_uuid = ?', $this->uuid)->order('object_name ASC');
     }
 }
diff --git a/library/Vspheredb/Web/Table/VmDiskUsageTable.php b/library/Vspheredb/Web/Table/VmDiskUsageTable.php
index 993a24d2..d834d5a7 100644
--- a/library/Vspheredb/Web/Table/VmDiskUsageTable.php
+++ b/library/Vspheredb/Web/Table/VmDiskUsageTable.php
@@ -4,32 +4,34 @@
 
 use gipfl\IcingaWeb2\Img;
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\Web\Widget\SimpleUsageBar;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
 use Icinga\Util\Format;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class VmDiskUsageTable extends ZfQueryBasedTable
 {
     protected $defaultAttributes = [
         'class' => ['vm-disk-usage-table', 'common-table', 'table-row-selectable'],
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    protected $totalSize = 0;
+    protected int $totalSize = 0;
 
-    protected $totalFree = 0;
+    protected int $totalFree = 0;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    /** @var string */
-    protected $uuid;
+    protected ?string $uuid = null;
 
-    private $root;
+    private object $root;
 
-    private $withHistory = false;
+    private bool $withHistory = false;
 
     public function __construct(VirtualMachine $vm)
     {
@@ -37,7 +39,7 @@ public function __construct(VirtualMachine $vm)
         $this->setVm($vm);
     }
 
-    protected function setVm(VirtualMachine $vm)
+    protected function setVm(VirtualMachine $vm): static
     {
         $this->vm = $vm;
         $this->uuid = $vm->get('uuid');
@@ -45,11 +47,12 @@ protected function setVm(VirtualMachine $vm)
         return $this;
     }
 
-    public function getColumnsToBeRendered()
+    public function getColumnsToBeRendered(): ?array
     {
         if (count($this) === 0) {
             $this->prepend($this->translate('No guest disk found. Please check guest utilities'));
             $this->prepend(new SubTitle($this->translate('Guest Disk Usage'), 'chart-pie'));
+
             return null;
         }
 
@@ -59,16 +62,18 @@ public function getColumnsToBeRendered()
             $this->translate('Disk'),
             $this->translate('Size'),
             $this->translate('Free space'),
-            $this->translate('Usage'),
+            $this->translate('Usage')
         ];
     }
 
     /**
      * @param $row
-     * @return \ipl\Html\HtmlElement
-     * @throws \Icinga\Exception\NotFoundError
+     *
+     * @return HtmlElement
+     *
+     * @throws NotFoundError
      */
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $caption = $row->disk_path;
 
@@ -76,13 +81,10 @@ public function renderRow($row)
             $this->root = $row;
         }
 
-        $free = Format::bytes($row->free_space)
-            . sprintf(' (%0.3f%%)', ($row->free_space / $row->capacity) * 100);
+        $free = Format::bytes($row->free_space) . sprintf(' (%0.3f%%)', ($row->free_space / $row->capacity) * 100);
 
         $tr = $this::tr([
-            $this::td($caption, [
-                'title' => $caption
-            ]),
+            $this::td($caption, ['title' => $caption]),
             $this::td(Format::bytes($row->capacity), ['class' => 'vm-disk-usage-capacity']),
             $this::td($free, ['class' => 'vm-disk-usage-free']),
             $this::td($this->makeDisk($row), ['class' => 'vm-disk-usage-usage'])
@@ -111,7 +113,7 @@ public function renderRow($row)
                     'width'    => 480,
                     'start'    => $start,
                     'end'      => $end,
-                    'template' => 'vm_disk',
+                    'template' => 'vm_disk'
                 ]),
                 [
                     'colspan' => 4,
@@ -123,7 +125,7 @@ public function renderRow($row)
         return $tr;
     }
 
-    protected function fetchRows()
+    protected function fetchRows(): void
     {
         parent::fetchRows();
         if (count($this) === 0) {
@@ -135,34 +137,34 @@ protected function fetchRows()
             $this::th(Html::tag('strong', null, $this->translate('Total'))),
             $this::th(Format::bytes($this->totalSize), ['class' => 'vm-disk-usage-capacity']),
             $this::th($free, ['class' => 'vm-disk-usage-free']),
-            $this::th($this->makeDisk((object) [
-                'disk_path' => $this->translate('Total'),
-                'capacity'  => $this->totalSize,
-                'free_space' => $this->totalFree
-            ]), ['class' => 'vm-disk-usage-usage'])
+            $this::th(
+                $this->makeDisk((object) [
+                    'disk_path'  => $this->translate('Total'),
+                    'capacity'   => $this->totalSize,
+                    'free_space' => $this->totalFree
+                ]),
+                ['class' => 'vm-disk-usage-usage']
+            )
         ]));
     }
 
-    public function generateFooter()
+    public function generateFooter(): HtmlElement
     {
         return Html::tag('tfoot');
     }
 
-    protected function makeDisk($disk)
+    protected function makeDisk(object $disk): SimpleUsageBar
     {
         $used = $disk->capacity - $disk->free_space;
 
         return new SimpleUsageBar($used, $disk->capacity, $disk->disk_path);
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        return $this->db()->select()->from(
-            'vm_disk_usage',
-            ['disk_path', 'capacity', 'free_space']
-        )->where(
-            'vm_uuid = ?',
-            $this->uuid
-        )->order('disk_path');
+        return $this->db()->select()
+            ->from('vm_disk_usage', ['disk_path', 'capacity', 'free_space'])
+            ->where('vm_uuid = ?', $this->uuid)
+            ->order('disk_path');
     }
 }
diff --git a/library/Vspheredb/Web/Table/VmDisksTable.php b/library/Vspheredb/Web/Table/VmDisksTable.php
index 834c4488..c84bac4f 100644
--- a/library/Vspheredb/Web/Table/VmDisksTable.php
+++ b/library/Vspheredb/Web/Table/VmDisksTable.php
@@ -3,34 +3,32 @@
 namespace Icinga\Module\Vspheredb\Web\Table;
 
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\PerformanceData\IcingaRrd\RrdImg;
 use Icinga\Module\Vspheredb\Web\Widget\OverallStatusRenderer;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
 use Icinga\Util\Format;
+use ipl\Html\FormattedString;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class VmDisksTable extends ZfQueryBasedTable
 {
-    protected $searchColumns = [
-        'object_name',
-    ];
+    protected $searchColumns = ['object_name'];
 
     protected $parentIds;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    /** @var string */
-    protected $uuid;
+    protected ?string $uuid = null;
 
-    /** @var string */
-    protected $moref;
+    protected ?string $moref = null;
 
-    /** @var OverallStatusRenderer */
-    protected $renderStatus;
+    protected OverallStatusRenderer $renderStatus;
 
-    protected $withPerfImages = false;
+    protected bool $withPerfImages = false;
 
     public function __construct(VirtualMachine $vm)
     {
@@ -40,7 +38,7 @@ public function __construct(VirtualMachine $vm)
         $this->setVm($vm);
     }
 
-    protected function setVm(VirtualMachine $vm)
+    protected function setVm(VirtualMachine $vm): static
     {
         $this->vm = $vm;
         $this->uuid = $vm->get('uuid');
@@ -49,7 +47,7 @@ protected function setVm(VirtualMachine $vm)
         return $this;
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $device = sprintf(
             '%s%d:%d',
@@ -68,18 +66,16 @@ public function renderRow($row)
                     Html::tag('br'),
                     $device,
                     Html::tag('br'),
-                    Format::bytes($row->capacity),
+                    Format::bytes($row->capacity)
                 ], ['class' => 'vm-disks-with-perf-image']),
                 $this->prepareImgColumn($device)
             ]);
-        } else {
-            return $this->row([
-                $this->formatSimple($row, $device)
-            ]);
         }
+
+        return $this->row([$this->formatSimple($row, $device)]);
     }
 
-    protected function formatSimple($row, $device)
+    protected function formatSimple(object $row, string $device): FormattedString
     {
         return Html::sprintf(
             '%s (%s): %s',
@@ -89,35 +85,37 @@ protected function formatSimple($row, $device)
         );
     }
 
-    protected function prepareImgColumn($device)
+    protected function prepareImgColumn($device): ?HtmlElement
     {
         if ($this->withPerfImages) {
             return $this::td([
                 RrdImg::vmDiskSeeks($this->moref, $device),
                 RrdImg::vmDiskReadWrites($this->moref, $device),
-                RrdImg::vmDiskTotalLatency($this->moref, $device),
+                RrdImg::vmDiskTotalLatency($this->moref, $device)
             ]);
-        } else {
-            return null;
         }
+
+        return null;
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $uuid = $this->vm->get('uuid');
-        $query = $this->db()->select()->from(['vmd' => 'vm_disk'], [
-            'controller_label'    => 'vmhc.label',
-            'hardware_label'      => 'vmhw.label',
-            'hardware_key'        => 'vmhw.hardware_key',
-            'hardware_bus_number' => 'vmhc.bus_number',
-            'hardware_unit_nmber' => 'vmhw.unit_number',
-            'capacity'            => 'vmd.capacity',
-        ])
-        ->join(['vmhw' => 'vm_hardware'], 'vmd.vm_uuid = vmhw.vm_uuid AND vmd.hardware_key = vmhw.hardware_key', [])
-        ->join(['vmhc' => 'vm_hardware'], 'vmhw.vm_uuid = vmhc.vm_uuid AND vmhw.controller_key = vmhc.hardware_key', [])
-        ->where('vmd.vm_uuid = ?', $uuid)
-        ->order('hardware_label');
-
-        return $query;
+        return $this->db()->select()
+            ->from(['vmd' => 'vm_disk'], [
+                'controller_label'    => 'vmhc.label',
+                'hardware_label'      => 'vmhw.label',
+                'hardware_key'        => 'vmhw.hardware_key',
+                'hardware_bus_number' => 'vmhc.bus_number',
+                'hardware_unit_nmber' => 'vmhw.unit_number',
+                'capacity'            => 'vmd.capacity'
+            ])
+            ->join(['vmhw' => 'vm_hardware'], 'vmd.vm_uuid = vmhw.vm_uuid AND vmd.hardware_key = vmhw.hardware_key', [])
+            ->join(
+                ['vmhc' => 'vm_hardware'],
+                'vmhw.vm_uuid = vmhc.vm_uuid AND vmhw.controller_key = vmhc.hardware_key',
+                []
+            )
+            ->where('vmd.vm_uuid = ?', $this->vm->get('uuid'))
+            ->order('hardware_label');
     }
 }
diff --git a/library/Vspheredb/Web/Table/VmNetworkAdapterTable.php b/library/Vspheredb/Web/Table/VmNetworkAdapterTable.php
index c72cb674..095ccab0 100644
--- a/library/Vspheredb/Web/Table/VmNetworkAdapterTable.php
+++ b/library/Vspheredb/Web/Table/VmNetworkAdapterTable.php
@@ -2,33 +2,32 @@
 
 namespace Icinga\Module\Vspheredb\Web\Table;
 
-use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\PerformanceData\IcingaRrd\RrdImg;
-use Icinga\Module\Vspheredb\Web\Widget\GrafanaVmPanel;
 use Icinga\Module\Vspheredb\Web\Widget\MacAddress;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
+use ipl\Html\FormattedString;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
+use stdClass;
+use Zend_Db_Select;
 
 class VmNetworkAdapterTable extends ZfQueryBasedTable
 {
     protected $defaultAttributes = [
         'class' => 'common-table',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    /** @var string */
-    protected $moref;
+    protected ?string $moref;
 
-    protected $withPerfImages = false;
-    /**
-     * @var array
-     */
-    protected $ipAddresses;
+    protected bool $withPerfImages = false;
+
+    protected stdClass $ipAddresses;
 
     public function __construct(VirtualMachine $vm)
     {
@@ -39,45 +38,38 @@ public function __construct(VirtualMachine $vm)
         parent::__construct($vm->getConnection());
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         // $this->add($this::row([
         //     new GrafanaVmPanel($this->vm->object(), [1, 3], $row->label, 'All')
         // ]));
         if ($this->withPerfImages) {
-            return $this::row([
-                $this->formatMultiLine($row),
-                $this->prepareRowImages($row),
-            ]);
-        } else {
-            return $this::row([$this->formatSimple($row)]);
+            return $this::row([$this->formatMultiLine($row), $this->prepareRowImages($row)]);
         }
+
+        return $this::row([$this->formatSimple($row)]);
     }
 
-    protected function linkToPortGroup($row)
+    protected function linkToPortGroup($row): string|FormattedString
     {
         if ($row->port_key === null) {
             return ''; // TODO: explain (no portgroup -> ESXi?)
         } elseif ($row->portgroup_uuid === null) {
-            return \sprintf($this->translate('Port %s'), $row->port_key);
-        } else {
-            return Html::sprintf(
-                'Port %s on %s',
-                $row->port_key,
-                $row->portgroup_name
-                /* // TODO:
-                // Link::create(
-                //     $row->portgroup_name,
-                //     'vspheredb/portgroup',
-                //     ['uuid' => Util::niceUuid($row->portgroup_uuid)],
-                //     ['data-base-target' => '_next']
-                // )
-                */
-            );
+            return sprintf($this->translate('Port %s'), $row->port_key);
         }
+
+        return Html::sprintf('Port %s on %s', $row->port_key, $row->portgroup_name);
+        /* // TODO:
+        // Link::create(
+        //     $row->portgroup_name,
+        //     'vspheredb/portgroup',
+        //     ['uuid' => Util::niceUuid($row->portgroup_uuid)],
+        //     ['data-base-target' => '_next']
+        // )
+        */
     }
 
-    protected function formatSimple($row)
+    protected function formatSimple($row): FormattedString
     {
         $ipInfo = $this->ipAddresses->{$row->hardware_key} ?? null;
         if ($ipInfo) {
@@ -93,17 +85,11 @@ protected function formatSimple($row)
             $aIpInfo = [];
             foreach ($ipInfo->addresses as $address) {
                 // Explicit check for isset, as WP had a workaround skipping the property
-                if (! isset($address->state) || $address->state === null) {
-                    $aIpInfo[] = sprintf('%s/%s', $address->address, $address->prefixLength);
-                } else {
-                    $aIpInfo[] = sprintf('%s/%s (%s)', $address->address, $address->prefixLength, $address->state);
-                }
-            }
-            if (empty($aIpInfo)) {
-                $aIpInfo = '';
-            } else {
-                $aIpInfo = implode(', ', $aIpInfo);
+                $aIpInfo = ! isset($address->state)
+                    ? sprintf('%s/%s', $address->address, $address->prefixLength)
+                    : sprintf('%s/%s (%s)', $address->address, $address->prefixLength, $address->state);
             }
+            $aIpInfo = empty($aIpInfo) ? '' : implode(', ', $aIpInfo);
         } else {
             $mainIpInfo = '';
             $aIpInfo = '';
@@ -121,7 +107,7 @@ protected function formatSimple($row)
         );
     }
 
-    protected function formatMultiLine($row)
+    protected function formatMultiLine($row): array
     {
         return [
             Html::tag('strong', $row->label),
@@ -133,37 +119,28 @@ protected function formatMultiLine($row)
         ];
     }
 
-    protected function prepareRowImages($row)
+    protected function prepareRowImages($row): array
     {
         return [
             RrdImg::vmIfTraffic($this->moref, $row->hardware_key),
-            RrdImg::vmIfPackets($this->moref, $row->hardware_key),
+            RrdImg::vmIfPackets($this->moref, $row->hardware_key)
         ];
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['vna' => 'vm_network_adapter'],
-            [
+        return $this->db()->select()
+            ->from(['vna' => 'vm_network_adapter'], [
                 'vh.label',
                 'vna.hardware_key',
                 'vna.port_key',
                 'vna.mac_address',
                 'vna.address_type',
                 'vna.portgroup_uuid',
-                'portgroup_name' => 'pgo.object_name',
-            ]
-        )->join(
-            ['vh' => 'vm_hardware'],
-            'vh.vm_uuid = vna.vm_uuid AND vh.hardware_key = vna.hardware_key',
-            []
-        )->joinLeft(
-            ['pgo' => 'object'],
-            'pgo.uuid = vna.portgroup_uuid',
-            []
-        )->where('vna.vm_uuid = ?', $this->vm->get('uuid'))->order('vh.label ASC');
-
-        return $query;
+                'portgroup_name' => 'pgo.object_name'
+            ])
+            ->join(['vh' => 'vm_hardware'], 'vh.vm_uuid = vna.vm_uuid AND vh.hardware_key = vna.hardware_key', [])
+            ->joinLeft(['pgo' => 'object'], 'pgo.uuid = vna.portgroup_uuid', [])
+            ->where('vna.vm_uuid = ?', $this->vm->get('uuid'))->order('vh.label ASC');
     }
 }
diff --git a/library/Vspheredb/Web/Table/VmSnapshotTable.php b/library/Vspheredb/Web/Table/VmSnapshotTable.php
index 614c511e..3e08e109 100644
--- a/library/Vspheredb/Web/Table/VmSnapshotTable.php
+++ b/library/Vspheredb/Web/Table/VmSnapshotTable.php
@@ -3,20 +3,22 @@
 namespace Icinga\Module\Vspheredb\Web\Table;
 
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Date\DateFormatter;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\Web\Widget\SubTitle;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class VmSnapshotTable extends ZfQueryBasedTable
 {
     protected $defaultAttributes = [
         'class' => ['common-table', 'day-time-table'],
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
     public function __construct(VirtualMachine $vm)
     {
@@ -24,25 +26,23 @@ public function __construct(VirtualMachine $vm)
         $this->setVm($vm);
     }
 
-    protected function setVm(VirtualMachine $vm)
+    protected function setVm(VirtualMachine $vm): static
     {
         $this->vm = $vm;
 
         return $this;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         parent::assemble();
         if (count($this) === 0) {
-            $this->prepend(
-                Html::tag('p', null, $this->translate('No snapshots have been created for this VM'))
-            );
+            $this->prepend(Html::tag('p', null, $this->translate('No snapshots have been created for this VM')));
         }
         $this->prepend(new SubTitle($this->translate('Snapshots'), 'history'));
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $this->renderDayIfNew($row->ts_create / 1000);
 
@@ -54,16 +54,11 @@ public function renderRow($row)
         ]);
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            'vm_snapshot'
-        )->order('ts_create DESC');
-
-        if ($this->vm) {
-            $query->where('vm_uuid = ?', $this->vm->get('uuid'));
-        }
-
-        return $query;
+        return $this->db()->select()
+            ->from('vm_snapshot')
+            ->where('vm_uuid = ?', $this->vm->get('uuid'))
+            ->order('ts_create DESC');
     }
 }
diff --git a/library/Vspheredb/Web/Table/VmsOnDatastoreTable.php b/library/Vspheredb/Web/Table/VmsOnDatastoreTable.php
index c82be07b..1d51623e 100644
--- a/library/Vspheredb/Web/Table/VmsOnDatastoreTable.php
+++ b/library/Vspheredb/Web/Table/VmsOnDatastoreTable.php
@@ -5,38 +5,34 @@
 use gipfl\IcingaWeb2\Icon;
 use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Date\DateFormatter;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
 use Icinga\Module\Vspheredb\DbObject\Datastore;
 use Icinga\Module\Vspheredb\Util;
 use Icinga\Module\Vspheredb\Web\Widget\DatastoreUsage;
 use Icinga\Util\Format;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class VmsOnDatastoreTable extends ZfQueryBasedTable
 {
-    protected $searchColumns = [
-        'object_name',
-    ];
+    protected $searchColumns = ['object_name'];
 
-    /** @var Datastore */
-    protected $datastore;
+    protected ?Datastore $datastore = null;
 
-    /** @var string */
-    protected $uuid;
+    protected ?string $uuid = null;
 
-    /** @var int */
-    protected $capacity;
+    protected ?int $capacity = null;
 
-    /** @var int */
-    protected $uncommitted;
+    protected ?int $uncommitted = null;
 
-    public static function create(Datastore $datastore)
+    public static function create(Datastore $datastore): VmsOnDatastoreTable
     {
-        $tbl = new static($datastore->getConnection());
-        return $tbl->setDatastore($datastore);
+        return (new static($datastore->getConnection()))->setDatastore($datastore);
     }
 
-    protected function setDatastore(Datastore $datastore)
+    protected function setDatastore(Datastore $datastore): static
     {
         $this->datastore   = $datastore;
         $this->uuid        = $datastore->get('uuid');
@@ -46,17 +42,17 @@ protected function setDatastore(Datastore $datastore)
         return $this;
     }
 
-    public function getColumnsToBeRendered()
+    public function getColumnsToBeRendered(): array
     {
         return [
             $this->translate('Virtual Machine'),
             $this->translate('Size'),
             $this->translate('Usage'),
-            $this->translate('On Datastore'),
+            $this->translate('On Datastore')
         ];
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
         $row->object_name = Anonymizer::anonymizeString($row->object_name);
         $size = $row->committed + $row->uncommitted;
@@ -64,19 +60,16 @@ public function renderRow($row)
             $row->object_name,
             'vspheredb/vm',
             Util::uuidParams($row->uuid),
-            ['title' => sprintf(
-                $this->translate('Virtual Machine: %s'),
-                $row->object_name
-            )]
+            ['title' => sprintf($this->translate('Virtual Machine: %s'), $row->object_name)]
         );
 
-        $usage = new DatastoreUsage($this->datastore);
-        $usage->setCapacity($size);
+        $usage = (new DatastoreUsage($this->datastore))
+            ->setCapacity($size)
+            ->addDiskFromDbRow($row);
         $usage->getAttributes()->add('class', 'compact');
-        $usage->addDiskFromDbRow($row);
-        $dsUsage = new DatastoreUsage($this->datastore);
+        $dsUsage = (new DatastoreUsage($this->datastore))
+            ->addDiskFromDbRow($row);
         $dsUsage->getAttributes()->add('class', 'compact');
-        $dsUsage->addDiskFromDbRow($row);
 
         $tr = $this::tr([
             $this::td($caption, ['class' => 'vm-on-datastore-caption']),
@@ -100,23 +93,17 @@ public function renderRow($row)
         return $tr;
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
-        $query = $this->db()->select()->from(
-            ['o' => 'object'],
-            [
+        return $this->db()->select()
+            ->from(['o' => 'object'], [
                 'uuid'        => 'o.uuid',
                 'object_name' => 'o.object_name',
                 'committed'   => 'vdu.committed',
                 'uncommitted' => 'vdu.uncommitted',
-                'ts_updated'  => 'vdu.ts_updated',
-            ]
-        )->join(
-            ['vdu' => 'vm_datastore_usage'],
-            'vdu.vm_uuid = o.uuid',
-            []
-        )->where('vdu.datastore_uuid = ?', $this->uuid)->order('object_name ASC');
-
-        return $query;
+                'ts_updated'  => 'vdu.ts_updated'
+            ])
+            ->join(['vdu' => 'vm_datastore_usage'], 'vdu.vm_uuid = o.uuid', [])
+            ->where('vdu.datastore_uuid = ?', $this->uuid)->order('object_name ASC');
     }
 }
diff --git a/library/Vspheredb/Web/Table/VmsWithDuplicateProperty.php b/library/Vspheredb/Web/Table/VmsWithDuplicateProperty.php
index 180241f9..bb783154 100644
--- a/library/Vspheredb/Web/Table/VmsWithDuplicateProperty.php
+++ b/library/Vspheredb/Web/Table/VmsWithDuplicateProperty.php
@@ -4,44 +4,38 @@
 
 use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Table\ZfQueryBasedTable;
+use gipfl\ZfDb\Select;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\Util;
+use ipl\Html\HtmlElement;
+use Zend_Db_Select;
 
 class VmsWithDuplicateProperty extends ZfQueryBasedTable
 {
     protected $defaultAttributes = [
         'class' => ['common-table', 'table-row-selectable'],
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
-    protected $searchColumns = [
-        'object_name',
-    ];
+    protected $searchColumns = ['object_name'];
 
-    protected $property;
+    protected ?string $property = null;
 
-    protected $propertyTitle;
+    protected ?string $propertyTitle = null;
 
-    protected $lastValue;
+    protected ?string $lastValue = null;
 
-    public static function create(Db $db, $property, $title)
+    public static function create(Db $db, string $property, string $title): static
     {
-        $table = new static($db);
-        $table->property = $property;
-        $table->propertyTitle = $title;
-
-        return $table;
+        return (new static($db))->setProperty($property, $title);
     }
 
-    public function getColumnsToBeRendered()
+    public function getColumnsToBeRendered(): array
     {
-        return [
-            $this->propertyTitle,
-            $this->translate('Name'),
-        ];
+        return [$this->propertyTitle, $this->translate('Name')];
     }
 
-    public function getColor()
+    public function getColor(): string
     {
         if (count($this) > 0) {
             return 'yellow';
@@ -50,7 +44,7 @@ public function getColor()
         return 'green';
     }
 
-    public function setProperty($name, $title)
+    public function setProperty(string $name, string $title): static
     {
         $this->property = $name;
         $this->propertyTitle = $title;
@@ -58,26 +52,16 @@ public function setProperty($name, $title)
         return $this;
     }
 
-    public function renderRow($row)
+    public function renderRow($row): HtmlElement
     {
-        $caption = Link::create(
-            $row->object_name,
-            'vspheredb/vm',
-            Util::uuidParams($row->uuid)
-        );
+        $caption = Link::create($row->object_name, 'vspheredb/vm', Util::uuidParams($row->uuid));
 
         $value = $row->{$this->property};
 
         if ($value === $this->lastValue) {
-            $tr = $this::row([
-                '',
-                $caption,
-            ]);
+            $tr = $this::row(['', $caption]);
         } else {
-            $tr = $this::row([
-                $value,
-                $caption,
-            ]);
+            $tr = $this::row([$value, $caption]);
             $this->lastValue = $value;
         }
         $tr->getAttributes()->add('class', [$row->runtime_power_state, $row->overall_status]);
@@ -85,34 +69,28 @@ public function renderRow($row)
         return $tr;
     }
 
-    public function prepareQuery()
+    public function prepareQuery(): Select|Zend_Db_Select
     {
         $db = $this->db();
 
         $property = $this->property;
         $this->searchColumns[] = $property;
-        $duplicateQuery = $db->select()->from('virtual_machine', $property)
+        $duplicateQuery = $db->select()
+            ->from('virtual_machine', $property)
             ->where("$property IS NOT NULL")
             ->group($property)
             ->having('(COUNT(*) > 1)');
 
-        return $db->select()->from(
-            ['vm' => 'virtual_machine'],
-            [
+        return $db->select()
+            ->from(['vm' => 'virtual_machine'], [
                 'o.uuid',
                 'vm.guest_host_name',
                 "vm.$property",
                 'vm.runtime_power_state',
-                'o.overall_status',
-            ]
-        )->join(
-            ['o' => 'object'],
-            'o.uuid = vm.uuid',
-            ['o.object_name']
-        )->join(
-            ['dup' => $duplicateQuery],
-            "vm.$property = dup.$property",
-            []
-        )->order($property)->order('object_name');
+                'o.overall_status'
+            ])
+            ->join(['o' => 'object'], 'o.uuid = vm.uuid', ['o.object_name'])
+            ->join(['dup' => $duplicateQuery], "vm.$property = dup.$property", [])
+            ->order($property)->order('object_name');
     }
 }
diff --git a/library/Vspheredb/Web/Table/VsphereApiConnectionTable.php b/library/Vspheredb/Web/Table/VsphereApiConnectionTable.php
index 8c14799a..ce755db8 100644
--- a/library/Vspheredb/Web/Table/VsphereApiConnectionTable.php
+++ b/library/Vspheredb/Web/Table/VsphereApiConnectionTable.php
@@ -4,12 +4,12 @@
 
 class VsphereApiConnectionTable extends ArrayTable
 {
-    public function getColumnsToBeRendered()
+    public function getColumnsToBeRendered(): array
     {
         return [
             $this->translate('VCenter'),
             $this->translate('Server'),
-            $this->translate('State'),
+            $this->translate('State')
         ];
     }
 }
diff --git a/library/Vspheredb/Web/Tabs/ConfigTabs.php b/library/Vspheredb/Web/Tabs/ConfigTabs.php
index 6ba1d6de..8d773bbe 100644
--- a/library/Vspheredb/Web/Tabs/ConfigTabs.php
+++ b/library/Vspheredb/Web/Tabs/ConfigTabs.php
@@ -2,17 +2,16 @@
 
 namespace Icinga\Module\Vspheredb\Web\Tabs;
 
-use ipl\I18n\Translation;
-use gipfl\IcingaWeb2\Widget\Tabs;
 use Exception;
+use gipfl\IcingaWeb2\Widget\Tabs;
 use Icinga\Module\Vspheredb\Db;
+use ipl\I18n\Translation;
 
 class ConfigTabs extends Tabs
 {
     use Translation;
 
-    /** @var Db|null  */
-    protected $connection;
+    protected ?Db $connection;
 
     public function __construct(?Db $connection = null)
     {
@@ -21,14 +20,14 @@ public function __construct(?Db $connection = null)
         $this->assemble();
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         if ($this->connection) {
             $migrations = Db::migrationsForDb($this->connection);
         } else {
             try {
                 $migrations = Db::migrationsForDb(Db::newConfiguredInstance());
-            } catch (Exception $e) {
+            } catch (Exception) {
                 $migrations = null;
             }
         }
@@ -36,23 +35,23 @@ protected function assemble()
         if ($migrations && $migrations->hasSchema()) {
             $this->add('servers', [
                 'label' => $this->translate('Servers'),
-                'url' => 'vspheredb/configuration/servers',
+                'url'   => 'vspheredb/configuration/servers'
             ]);
             $this->add('perfdata', [
                 'label' => $this->translate('Performance Data'),
-                'url'   => 'vspheredb/perfdata/consumers',
+                'url'   => 'vspheredb/perfdata/consumers'
             ]);
 
             // Disable Tab unless #160 is ready
             $this->add('monitoring', [
                 'label' => $this->translate('Monitoring'),
-                'url' => 'vspheredb/configuration/monitoring',
+                'url'   => 'vspheredb/configuration/monitoring'
             ]);
         }
 
         $this->add('database', [
             'label' => $this->translate('Database'),
-            'url'   => 'vspheredb/configuration/database',
+            'url'   => 'vspheredb/configuration/database'
         ]);
     }
 }
diff --git a/library/Vspheredb/Web/Tabs/MainTabs.php b/library/Vspheredb/Web/Tabs/MainTabs.php
index 7b80bf76..23d3ca64 100644
--- a/library/Vspheredb/Web/Tabs/MainTabs.php
+++ b/library/Vspheredb/Web/Tabs/MainTabs.php
@@ -2,21 +2,19 @@
 
 namespace Icinga\Module\Vspheredb\Web\Tabs;
 
-use ipl\I18n\Translation;
-use gipfl\IcingaWeb2\Widget\Tabs;
 use Exception;
+use gipfl\IcingaWeb2\Widget\Tabs;
 use Icinga\Authentication\Auth;
 use Icinga\Module\Vspheredb\Db;
+use ipl\I18n\Translation;
 
 class MainTabs extends Tabs
 {
     use Translation;
 
-    /** @var Db|null  */
-    protected $connection;
+    protected ?Db $connection;
 
-    /** @var Auth */
-    protected $auth;
+    protected Auth $auth;
 
     public function __construct(Auth $auth, ?Db $connection = null)
     {
@@ -26,14 +24,14 @@ public function __construct(Auth $auth, ?Db $connection = null)
         $this->assemble();
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         if ($this->connection) {
             $connection = $this->connection;
         } else {
             try {
                 $connection = Db::newConfiguredInstance();
-            } catch (Exception $e) {
+            } catch (Exception) {
                 $connection = null;
             }
         }
@@ -44,8 +42,8 @@ protected function assemble()
 
             if ($migrations->hasSchema()) {
                 $this->add('vcenters', [
-                    'label'     => $this->translate('vCenters'),
-                    'url'       => 'vspheredb/vcenters',
+                    'label' => $this->translate('vCenters'),
+                    'url'   => 'vspheredb/vcenters'
                 ]);
             }
         } else {
@@ -55,7 +53,7 @@ protected function assemble()
         if ($isAdmin && $migrations && $migrations->hasSchema()) {
             $this->add('daemon', [
                 'label' => $this->translate('Daemon'),
-                'url' => 'vspheredb/daemon',
+                'url'   => 'vspheredb/daemon'
             ]);
         }
     }
diff --git a/library/Vspheredb/Web/Tabs/VCenterTabs.php b/library/Vspheredb/Web/Tabs/VCenterTabs.php
index 1382c1e8..23e37713 100644
--- a/library/Vspheredb/Web/Tabs/VCenterTabs.php
+++ b/library/Vspheredb/Web/Tabs/VCenterTabs.php
@@ -3,6 +3,7 @@
 namespace Icinga\Module\Vspheredb\Web\Tabs;
 
 use gipfl\IcingaWeb2\Widget\Tabs;
+use gipfl\Translation\TranslationHelper;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use ipl\I18n\Translation;
 use Ramsey\Uuid\Uuid;
@@ -11,8 +12,7 @@ class VCenterTabs extends Tabs
 {
     use Translation;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     public function __construct(VCenter $vCenter)
     {
@@ -21,21 +21,21 @@ public function __construct(VCenter $vCenter)
         $this->assemble();
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $hexUuid = Uuid::fromBytes($this->vCenter->getUuid())->toString();
         $this->add('vcenter', [
-            'label' => $this->translate('vCenter'),
-            'url'   => 'vspheredb/vcenter',
-            'urlParams' => ['vcenter' => $hexUuid],
+            'label'     => $this->translate('vCenter'),
+            'url'       => 'vspheredb/vcenter',
+            'urlParams' => ['vcenter' => $hexUuid]
         ])->add('clusters', [
-            'label' => $this->translate('Clusters'),
-            'url'   => 'vspheredb/resources/clusters',
-            'urlParams' => ['vcenter' => $hexUuid],
+            'label'     => $this->translate('Clusters'),
+            'url'       => 'vspheredb/resources/clusters',
+            'urlParams' => ['vcenter' => $hexUuid]
         ])->add('perfcounters', [
-            'label' => $this->translate('Counters'),
-            'url'   => 'vspheredb/perfdata/counters',
-            'urlParams' => ['vcenter' => $hexUuid],
+            'label'     => $this->translate('Counters'),
+            'url'       => 'vspheredb/perfdata/counters',
+            'urlParams' => ['vcenter' => $hexUuid]
         ]);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/AdditionalTableActions.php b/library/Vspheredb/Web/Widget/AdditionalTableActions.php
index 5785d06f..790a84b1 100644
--- a/library/Vspheredb/Web/Widget/AdditionalTableActions.php
+++ b/library/Vspheredb/Web/Widget/AdditionalTableActions.php
@@ -2,27 +2,25 @@
 
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
-use ipl\Html\Html;
-use ipl\Html\HtmlDocument;
 use gipfl\IcingaWeb2\Icon;
 use gipfl\IcingaWeb2\Link;
-use ipl\I18n\Translation;
 use gipfl\IcingaWeb2\Url;
 use Icinga\Authentication\Auth;
 use Icinga\Module\Vspheredb\Web\Table\BaseTable;
+use ipl\Html\Html;
+use ipl\Html\HtmlDocument;
+use ipl\Html\HtmlElement;
+use ipl\I18n\Translation;
 
 class AdditionalTableActions
 {
     use Translation;
 
-    /** @var Auth */
-    protected $auth;
+    protected Auth $auth;
 
-    /** @var Url */
-    protected $url;
+    protected Url $url;
 
-    /** @var BaseTable */
-    protected $table;
+    protected BaseTable $table;
 
     public function __construct(BaseTable $table, Auth $auth, Url $url)
     {
@@ -31,7 +29,7 @@ public function __construct(BaseTable $table, Auth $auth, Url $url)
         $this->table = $table;
     }
 
-    public function appendTo(HtmlDocument $parent)
+    public function appendTo(HtmlDocument $parent): static
     {
         $links = [];
         if ($this->hasPermission('vspheredb/export') && $this->urlAllowsExport($this->url)) {
@@ -75,28 +73,20 @@ protected function urlAllowsExport(Url $url): bool
         return in_array($url->getPath(), [
             'vspheredb/vms',
             'vspheredb/hosts',
-            'vspheredb/datastores',
+            'vspheredb/datastores'
         ]);
     }
 
-    protected function createShowSqlToggle()
+    protected function createShowSqlToggle(): Link
     {
         if ($this->url->getParam('format') === 'sql') {
-            $link = Link::create(
-                $this->translate('Hide SQL'),
-                $this->url->without('format')
-            );
-        } else {
-            $link = Link::create(
-                $this->translate('Show SQL'),
-                $this->url->with('format', 'sql')
-            );
+            return Link::create($this->translate('Hide SQL'), $this->url->without('format'));
         }
 
-        return $link;
+        return Link::create($this->translate('Show SQL'), $this->url->with('format', 'sql'));
     }
 
-    protected function toggleColumnsOptions()
+    protected function toggleColumnsOptions(): array
     {
         $links = [];
         $table = $this->table;
@@ -125,9 +115,7 @@ protected function toggleColumnsOptions()
             if (in_array($alias, $enabled)) {
                 $links[] = Link::create(
                     $title,
-                    $url->with('columns', implode(',', array_diff($enabled, [
-                        $alias
-                    ]))),
+                    $url->with('columns', implode(',', array_diff($enabled, [$alias]))),
                     null,
                     ['class' => 'icon-ok']
                 );
@@ -135,9 +123,7 @@ protected function toggleColumnsOptions()
                 $disabled[] = $alias;
                 $links[] = Link::create(
                     $title,
-                    $url->with('columns', implode(',', array_merge($enabled, [
-                        $alias
-                    ]))),
+                    $url->with('columns', implode(',', array_merge($enabled, [$alias]))),
                     null,
                     ['class' => 'icon-plus']
                 );
@@ -158,9 +144,9 @@ protected function toggleColumnsOptions()
         return $links;
     }
 
-    protected function moreOptions($links)
+    protected function moreOptions(array $links): HtmlElement
     {
-        $options = $this->ul([
+        return $this->ul([
             /*$this->li([
                 Link::create('Columns', '#', null, ['class' => 'icon-th-list']),
                 $this->linkList($this->toggleColumnsOptions())
@@ -168,13 +154,11 @@ protected function moreOptions($links)
             $this->li([
                 Link::create(Icon::create('down-open'), '#'),
                 $this->linkList($links)
-            ]),
+            ])
         ], ['class' => 'nav']);
-
-        return $options;
     }
 
-    protected function linkList($links)
+    protected function linkList(array $links): HtmlElement
     {
         $ul = Html::tag('ul');
 
@@ -185,22 +169,22 @@ protected function linkList($links)
         return $ul;
     }
 
-    protected function ulLi($content)
+    protected function ulLi($content): HtmlElement
     {
         return $this->ul($this->li($content));
     }
 
-    protected function ul($content, $attributes = null)
+    protected function ul(mixed $content, ?array $attributes = null): HtmlElement
     {
         return Html::tag('ul', $attributes, $content);
     }
 
-    protected function li($content)
+    protected function li(mixed $content): HtmlElement
     {
         return Html::tag('li', null, $content);
     }
 
-    protected function hasPermission($permission)
+    protected function hasPermission($permission): bool
     {
         return $this->auth->hasPermission($permission);
     }
diff --git a/library/Vspheredb/Web/Widget/Addon/IbmSpectrumProtectBackupRunDetails.php b/library/Vspheredb/Web/Widget/Addon/IbmSpectrumProtectBackupRunDetails.php
index 67b7dfee..3b82e60c 100644
--- a/library/Vspheredb/Web/Widget/Addon/IbmSpectrumProtectBackupRunDetails.php
+++ b/library/Vspheredb/Web/Widget/Addon/IbmSpectrumProtectBackupRunDetails.php
@@ -14,6 +14,7 @@ class IbmSpectrumProtectBackupRunDetails extends NameValueTable
 
     /**
      * IbmSpectrumProtectBackupRunDetails constructor.
+     *
      * @param IbmSpectrumProtect $details
      */
     public function __construct(IbmSpectrumProtect $details)
@@ -21,18 +22,18 @@ public function __construct(IbmSpectrumProtect $details)
         $attributes = $details->requireParsedAttributes();
 
         $optional = [
-            $this->translate('Schedule')      => $attributes['Schedule'],
-            $this->translate('Application Protection') => $attributes['Application Protection'],
+            $this->translate('Schedule')               => $attributes['Schedule'],
+            $this->translate('Application Protection') => $attributes['Application Protection']
         ];
 
         $this->addNameValuePairs([
-            $this->translate('Status') => $attributes['Status'],
+            $this->translate('Status')           => $attributes['Status'],
             $this->translate('Last Run Time')    => DateFormatter::formatDateTime($attributes['Last Run Time']),
             $this->translate('Data Transmitted') => Format::bytes($attributes['Data Transmitted']),
-            $this->translate('Duration')      => DateFormatter::formatDuration($attributes['Duration']),
-            $this->translate('Type')          => $attributes['Type'],
-            $this->translate('Data Mover')    => $attributes['Data Mover'],
-            $this->translate('Snapshot Type') => $attributes['Snapshot Type'],
+            $this->translate('Duration')         => DateFormatter::formatDuration($attributes['Duration']),
+            $this->translate('Type')             => $attributes['Type'],
+            $this->translate('Data Mover')       => $attributes['Data Mover'],
+            $this->translate('Snapshot Type')    => $attributes['Snapshot Type']
         ]);
 
         foreach ($optional as $name => $value) {
diff --git a/library/Vspheredb/Web/Widget/Addon/NetBackupRunDetails.php b/library/Vspheredb/Web/Widget/Addon/NetBackupRunDetails.php
index ce8779f9..de67587b 100644
--- a/library/Vspheredb/Web/Widget/Addon/NetBackupRunDetails.php
+++ b/library/Vspheredb/Web/Widget/Addon/NetBackupRunDetails.php
@@ -28,6 +28,7 @@ public function __construct(NetBackup $details)
                 $this->translate('Excluded'),
                 $this->translate('This VM has been excluded from Backup')
             );
+
             return;
         }
         if (isset($attributes['Job name'])) {
@@ -56,17 +57,15 @@ public function __construct(NetBackup $details)
         }
     }
 
-    protected function renderBackupHost($name)
+    protected function renderBackupHost(string $name): Link|string
     {
         try {
             // TODO: this is ugly.
             $lookup = new CheckRelatedLookup(Db::newConfiguredInstance());
-            $vm = $lookup->findOneBy('VirtualMachine', [
-                'guest_host_name' => $name
-            ]);
+            $vm = $lookup->findOneBy('VirtualMachine', ['guest_host_name' => $name]);
 
             return Link::create($name, 'vspheredb/vm', Util::uuidParams($vm->get('uuid')));
-        } catch (NotFoundError $e) {
+        } catch (NotFoundError) {
             return $name;
         }
     }
diff --git a/library/Vspheredb/Web/Widget/Addon/VRangerBackupRunDetails.php b/library/Vspheredb/Web/Widget/Addon/VRangerBackupRunDetails.php
index 3c525663..a570c495 100644
--- a/library/Vspheredb/Web/Widget/Addon/VRangerBackupRunDetails.php
+++ b/library/Vspheredb/Web/Widget/Addon/VRangerBackupRunDetails.php
@@ -22,7 +22,7 @@ public function __construct(VRangerBackup $details)
             $this->translate('Result')        => $attributes['Result'],
             $this->translate('Last Run Time') => DateFormatter::formatDateTime($attributes['Time']),
             $this->translate('Type')          => $attributes['Type'],
-            $this->translate('Repository')    => $attributes['Repository'],
+            $this->translate('Repository')    => $attributes['Repository']
         ]);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/Addon/VeeamBackupRunDetails.php b/library/Vspheredb/Web/Widget/Addon/VeeamBackupRunDetails.php
index a0bdf099..1541dd00 100644
--- a/library/Vspheredb/Web/Widget/Addon/VeeamBackupRunDetails.php
+++ b/library/Vspheredb/Web/Widget/Addon/VeeamBackupRunDetails.php
@@ -3,6 +3,7 @@
 namespace Icinga\Module\Vspheredb\Web\Widget\Addon;
 
 use gipfl\IcingaWeb2\Widget\NameValueTable;
+use gipfl\Translation\TranslationHelper;
 use Icinga\Date\DateFormatter;
 use Icinga\Module\Vspheredb\Addon\VeeamBackup;
 use ipl\I18n\Translation;
@@ -13,6 +14,7 @@ class VeeamBackupRunDetails extends NameValueTable
 
     /**
      * VeeamBackupRunDetails constructor.
+     *
      * @param VeeamBackup $details
      */
     public function __construct(VeeamBackup $details)
@@ -23,7 +25,7 @@ public function __construct(VeeamBackup $details)
             $this->translate('Job name')      => $attributes['Job name'],
             $this->translate('Last Run Time') => DateFormatter::formatDateTime($attributes['Time']),
             $this->translate('Backup host')   => $attributes['Backup host'],
-            $this->translate('Backup folder') => $attributes['Backup folder'],
+            $this->translate('Backup folder') => $attributes['Backup folder']
         ]);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/AlarmHeatmap.php b/library/Vspheredb/Web/Widget/AlarmHeatmap.php
index 207d6f16..a46d8dc3 100644
--- a/library/Vspheredb/Web/Widget/AlarmHeatmap.php
+++ b/library/Vspheredb/Web/Widget/AlarmHeatmap.php
@@ -3,14 +3,14 @@
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
 use Icinga\Module\Vspheredb\Db;
+use Zend_Db_Adapter_Abstract;
 use Zend_Db_Select as ZfSelect;
 
 class AlarmHeatmap
 {
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
 
-    protected $query;
+    protected ?ZfSelect $query = null;
 
     public function __construct(Db $connection)
     {
@@ -25,19 +25,18 @@ public function getEvents(): array
     protected function prepareQuery(): ZfSelect
     {
         $maxDays = 400;
-        return $this->db->select()->from('alarm_history', [
-            // TODO: / 86400 + offset
-            'day' => 'DATE(FROM_UNIXTIME(ts_event_ms / 1000))',
-            'cnt' => 'COUNT(*)'
-        ])->where('ts_event_ms > ?', time() * 1000 - 86400 * $maxDays * 1000)->group('day');
+        return $this->db->select()
+            ->from('alarm_history', [
+                // TODO: / 86400 + offset
+                'day' => 'DATE(FROM_UNIXTIME(ts_event_ms / 1000))',
+                'cnt' => 'COUNT(*)'
+            ])
+            ->where('ts_event_ms > ?', time() * 1000 - 86400 * $maxDays * 1000)
+            ->group('day');
     }
 
     protected function getQuery(): ZfSelect
     {
-        if ($this->query === null) {
-            $this->query = $this->prepareQuery();
-        }
-
-        return $this->query;
+        return $this->query ??= $this->prepareQuery();
     }
 }
diff --git a/library/Vspheredb/Web/Widget/BiosInfo.php b/library/Vspheredb/Web/Widget/BiosInfo.php
index 6a621219..a8f2b4bd 100644
--- a/library/Vspheredb/Web/Widget/BiosInfo.php
+++ b/library/Vspheredb/Web/Widget/BiosInfo.php
@@ -7,19 +7,18 @@
 
 class BiosInfo extends HtmlDocument
 {
-    /** @var HostSystem */
-    protected $host;
+    protected HostSystem $host;
 
     public function __construct(HostSystem $host)
     {
         $this->host = $host;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $host = $this->host;
         $version = $host->get('bios_version');
-        if ($releaseDate = $host->get('bios_release_date')) {
+        if ($host->get('bios_release_date')) {
             $releaseDate = date('Y-m-d', strtotime($host->get('bios_release_date')));
             $this->add(sprintf('%s (%s)', $version, $releaseDate));
         }
diff --git a/library/Vspheredb/Web/Widget/CalendarForEvents.php b/library/Vspheredb/Web/Widget/CalendarForEvents.php
index 1e0996ed..114f2bd2 100644
--- a/library/Vspheredb/Web/Widget/CalendarForEvents.php
+++ b/library/Vspheredb/Web/Widget/CalendarForEvents.php
@@ -12,36 +12,30 @@ class CalendarForEvents extends HtmlDocument
 {
     use Translation;
 
-    /** @var VMotionHeatmap|AlarmHeatmap */
-    protected $calendars;
+    protected VMotionHeatmap|AlarmHeatmap $calendars;
 
-    /** @var Url */
-    protected $baseUrl;
+    protected Url $baseUrl;
 
     /** @var int[] [r, g, b] */
-    protected $colors;
+    protected array $colors;
 
-    public function __construct($calendars, Url $baseUrl, array $colors)
+    public function __construct(VMotionHeatmap|AlarmHeatmap $calendars, Url $baseUrl, array $colors)
     {
         $this->calendars = $calendars;
         $this->baseUrl = $baseUrl;
         $this->colors = $colors;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $events = $this->calendars->getEvents();
         if (empty($events)) {
+            $maxPerDay = 0;
             $this->add(Hint::warning($this->translate('No events found')));
-            $maxPerDay = $total = 0;
         } else {
             $maxPerDay = max($events);
             $total = array_sum($events);
-            $this->add(Hint::ok(
-                $this->translate('%s events, max %s per day'),
-                $total,
-                $maxPerDay
-            ));
+            $this->add(Hint::ok($this->translate('%s events, max %s per day'), $total, $maxPerDay));
         }
 
         $eventsPerMonth = [];
@@ -49,9 +43,7 @@ protected function assemble()
             $month = substr($day, 0, 7);
             $eventsPerMonth[$month][$day] = $count;
         }
-        $div = Html::tag('div', [
-            'class' => 'event-heatmap-calendars',
-        ]);
+        $div = Html::tag('div', ['class' => 'event-heatmap-calendars']);
 
         $months = $this->prepareMonthList();
         $colors = $this->colors;
diff --git a/library/Vspheredb/Web/Widget/CalendarMonthSummary.php b/library/Vspheredb/Web/Widget/CalendarMonthSummary.php
index d7560de2..d094d9f4 100644
--- a/library/Vspheredb/Web/Widget/CalendarMonthSummary.php
+++ b/library/Vspheredb/Web/Widget/CalendarMonthSummary.php
@@ -6,6 +6,7 @@
 use gipfl\Format\LocalTimeFormat;
 use gipfl\IcingaWeb2\Link;
 use gipfl\IcingaWeb2\Url;
+use ipl\Html\Attributes;
 use ipl\Html\HtmlElement;
 use ipl\Html\Table;
 use ipl\I18n\Translation;
@@ -17,38 +18,38 @@ class CalendarMonthSummary extends Table
 
     protected $defaultAttributes = [
         'data-base-target' => '_next',
-        'class'            => 'calendar',
+        'class'            => 'calendar'
     ];
 
-    protected $today;
+    protected ?string $today = null;
 
-    protected $year;
+    protected int $year;
 
-    protected $month;
+    protected int $month;
 
-    protected $strMonth;
+    protected string $strMonth;
 
-    protected $strToday;
+    protected string $strToday;
 
-    protected $days = [];
+    protected array $days = [];
 
-    protected $calendar;
+    protected Calendar $calendar;
 
-    protected $showWeekNumbers = true;
+    protected bool $showWeekNumbers = true;
 
-    protected $showOtherMonth = false;
+    protected bool $showOtherMonth = false;
 
-    protected $showGrayFuture = true;
+    protected bool $showGrayFuture = true;
 
-    protected $title;
+    protected ?string $title = null;
 
-    protected $color = '255, 128, 0';
+    protected string $color = '255, 128, 0';
 
-    protected $forcedMax;
+    protected ?int $forcedMax = null;
 
-    protected $timeFormat;
+    protected LocalTimeFormat $timeFormat;
 
-    public function __construct($year, $month)
+    public function __construct(int $year, int $month)
     {
         $this->calendar = new Calendar();
         $this->year = $year;
@@ -58,24 +59,20 @@ public function __construct($year, $month)
         $this->timeFormat = new LocalTimeFormat();
     }
 
-    public function setRgb($red, $green, $blue)
+    public function setRgb(int $red, int $green, int $blue): static
     {
         $this->color = sprintf('%d, %d, %d', $red, $green, $blue);
 
         return $this;
     }
 
-    public function addEvents($events, Url $baseUrl)
+    public function addEvents(array $events, Url $baseUrl): static
     {
         if (empty($events)) {
             return $this;
         }
 
-        if ($this->forcedMax === null) {
-            $max = max($events);
-        } else {
-            $max = $this->forcedMax;
-        }
+        $max = $this->forcedMax ?? max($events);
 
         foreach ($events as $day => $count) {
             if (! $this->hasDay($day)) {
@@ -87,14 +84,14 @@ public function addEvents($events, Url $baseUrl)
             $alpha = $count / $max;
 
             if ($alpha > 0.4) {
-                $link->addAttributes(['class' => 'color-white']);
+                $link->addAttributes(Attributes::create(['class' => 'color-white']));
             }
 
             $style = (new StyleWithNonce())
                 ->setModule('vspheredb')
                 ->addFor($link, ['background-color' => sprintf('rgba(%s, %.2F)', $this->color, $alpha)]);
 
-            $link->addAttributes(['title' => sprintf('%d events', $count)]);
+            $link->addAttributes(Attributes::create(['title' => sprintf('%d events', $count)]));
 
             $this->getDay($day)->setContent([$link, $style]);
         }
@@ -102,45 +99,38 @@ public function addEvents($events, Url $baseUrl)
         return $this;
     }
 
-    public function markNow($now = null)
+    public function markNow(?int $now = null): static
     {
-        if ($now === null) {
-            $now = time();
-        }
-        $this->today = date('Y-m-d', $now);
+        $this->today = date('Y-m-d', $now ?? time());
 
         return $this;
     }
 
-    public function setTitle($title)
+    public function setTitle(string $title): static
     {
         $this->title = $title;
 
         return $this;
     }
 
-    protected function getTitle()
+    protected function getTitle(): string
     {
-        if ($this->title === null) {
-            $this->title = $this->getMonthName() . ' ' . $this->year;
-        }
-
-        return $this->title;
+        return $this->title ??= $this->getMonthName() . ' ' . $this->year;
     }
 
-    public function forceMax($max)
+    public function forceMax(int $max): static
     {
         $this->forcedMax = $max;
 
         return $this;
     }
 
-    protected function getMonthAsTimestamp()
+    protected function getMonthAsTimestamp(): int
     {
         return strtotime($this->strMonth . '-01');
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->setCaption($this->getTitle());
         $this->getHeader()->add($this->createWeekdayHeader());
@@ -194,40 +184,37 @@ protected function createDay(string $day): HtmlElement
         $this->days[$day] = $td;
 
         if ($otherMonth) {
-            $td->addAttributes(['class' => 'other-month']);
+            $td->addAttributes(Attributes::create(['class' => 'other-month']));
         } elseif ($this->showGrayFuture && $day > $this->strToday) {
-            $td->addAttributes(['class' => 'future-day']);
+            $td->addAttributes(Attributes::create(['class' => 'future-day']));
         }
 
         // TODO: today VS strToday?!
         if ($day === $this->today) {
-            $td->addAttributes(['class' => 'today']);
+            $td->addAttributes(Attributes::create(['class' => 'today']));
         }
 
         return $td;
     }
 
 
-    protected function weekRow($cw)
+    protected function weekRow($cw): HtmlElement
     {
         $row = Table::tr();
 
         if ($this->showWeekNumbers) {
-            $row->add(Table::th(sprintf('%02d', $cw), [
-                'title' => sprintf($this->translate('Calendar Week %d'), $cw)
-            ]));
+            $row->add(Table::th(sprintf('%02d', $cw), ['title' => sprintf($this->translate('Calendar Week %d'), $cw)]));
         }
 
         return $row;
     }
 
-    protected function getMonthName()
+    protected function getMonthName(): string
     {
         return $this->timeFormat->getMonthName($this->getMonthAsTimestamp());
-        return date('F', $this->getMonthAsTimestamp());
     }
 
-    protected function createWeekdayHeader()
+    protected function createWeekdayHeader(): HtmlElement
     {
         $cols = $this->calendar->listShortWeekDayNames();
         if ($this->showWeekNumbers) {
diff --git a/library/Vspheredb/Web/Widget/CheckPluginHelper.php b/library/Vspheredb/Web/Widget/CheckPluginHelper.php
index 117bdbff..30627151 100644
--- a/library/Vspheredb/Web/Widget/CheckPluginHelper.php
+++ b/library/Vspheredb/Web/Widget/CheckPluginHelper.php
@@ -11,11 +11,11 @@ class CheckPluginHelper
     public static function colorizeOutput(string $output): HtmlString
     {
         $pattern = '/\[(OK|WARNING|CRITICAL|UNKNOWN)]\s/';
-        $safeString = (new Text($output))->render();
-        $safeString = preg_replace_callback($pattern, function ($match) {
-            $state = strtolower($match[1]);
-            return Html::tag('span', ['class' => ['check-result', "state-$state"]], $match[1]) . ' ';
-        }, $safeString);
+        $safeString = preg_replace_callback($pattern, fn($match) => Html::tag(
+            'span',
+            ['class' => ['check-result', 'state-' . strtolower($match[1])]],
+            $match[1]
+        ) . ' ', (new Text($output))->render());
         return new HtmlString($safeString);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/CompactInOutSparkline.php b/library/Vspheredb/Web/Widget/CompactInOutSparkline.php
index c52cf9ed..4b8a6b5e 100644
--- a/library/Vspheredb/Web/Widget/CompactInOutSparkline.php
+++ b/library/Vspheredb/Web/Widget/CompactInOutSparkline.php
@@ -2,8 +2,10 @@
 
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
+use ipl\Html\Attributes;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 
 class CompactInOutSparkline extends BaseHtmlElement
 {
@@ -11,33 +13,34 @@ class CompactInOutSparkline extends BaseHtmlElement
 
     protected $defaultAttributes = ['class' => 'sparks'];
 
-    public function __construct($in, $out)
+    public function __construct(array|string|null $in, array|string|null $out)
     {
         if ($in !== null) {
             $this->add(
                 $this->makeSparkLine($in)
-                    ->addAttributes(['class' => 'in'])
+                    ->addAttributes(Attributes::create(['class' => 'in']))
             );
         }
 
         if ($out !== null && $out !== '0,0,0,0,0') {
             $this->add(
                 $this->makeSparkLine($this->negateString($out))
-                    ->addAttributes(['class' => 'out'])
+                    ->addAttributes(Attributes::create(['class' => 'out']))
             );
         }
     }
 
-    protected function negateString($valueString)
+    protected function negateString(string $valueString): string
     {
         return '-' . implode(',-', explode(',', $valueString));
     }
 
-    protected function makeSparkLine($values)
+    protected function makeSparkLine($values): ?HtmlElement
     {
         if ($values === null) {
             return null;
         }
+
         return Html::tag('span', [
             'class'            => 'sparkline',
             'sparkType'        => 'bar',
diff --git a/library/Vspheredb/Web/Widget/ComputeClusterHeader.php b/library/Vspheredb/Web/Widget/ComputeClusterHeader.php
index d30f2477..40649a59 100644
--- a/library/Vspheredb/Web/Widget/ComputeClusterHeader.php
+++ b/library/Vspheredb/Web/Widget/ComputeClusterHeader.php
@@ -2,14 +2,14 @@
 
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\DbObject\ComputeCluster;
 use ipl\Html\Html;
 use ipl\Html\HtmlDocument;
 
 class ComputeClusterHeader extends HtmlDocument
 {
-    /** @var ComputeCluster */
-    protected $computeCluster;
+    protected ComputeCluster $computeCluster;
 
     public function __construct(ComputeCluster $computeCluster)
     {
@@ -17,35 +17,20 @@ public function __construct(ComputeCluster $computeCluster)
     }
 
     /**
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws NotFoundError
      */
-    protected function assemble()
+    protected function assemble(): void
     {
         $computeCluster = $this->computeCluster;
         $object = $computeCluster->object();
         $overallStatusRenderer = new OverallStatusRenderer();
-        $icons = [
-            $overallStatusRenderer($object->get('overall_status')),
-        ];
+        $icons = [$overallStatusRenderer($object->get('overall_status'))];
 
         $stats = $computeCluster->calculateStats();
 
-        $cpu = new CpuAbsoluteUsage(
-            $stats->overall_cpu_usage,
-            $stats->hardware_cpu_cores
-        );
-        $mem = new MemoryUsage(
-            $stats->overall_memory_usage_mb,
-            $stats->hardware_memory_size_mb
-        );
-        $title = Html::tag('h1', [
-            $computeCluster->get('object_name'),
-            $icons
-        ]);
-        $this->add([
-            $cpu,
-            $title,
-            $mem
-        ]);
+        $cpu = new CpuAbsoluteUsage((int) $stats->overall_cpu_usage, $stats->hardware_cpu_cores);
+        $mem = new MemoryUsage($stats->overall_memory_usage_mb, $stats->hardware_memory_size_mb);
+        $title = Html::tag('h1', [$computeCluster->get('object_name'), $icons]);
+        $this->add([$cpu, $title, $mem]);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/Config/ProposeMigrations.php b/library/Vspheredb/Web/Widget/Config/ProposeMigrations.php
index afd60af2..fc61b502 100644
--- a/library/Vspheredb/Web/Widget/Config/ProposeMigrations.php
+++ b/library/Vspheredb/Web/Widget/Config/ProposeMigrations.php
@@ -8,6 +8,7 @@
 use Icinga\Authentication\Auth;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\Web\Form\ApplyMigrationsForm;
+use ipl\Html\Contract\Form;
 use ipl\Html\HtmlDocument;
 use ipl\I18n\Translation;
 use Psr\Http\Message\ServerRequestInterface;
@@ -27,20 +28,17 @@ class ProposeMigrations extends HtmlDocument
 {
     use Translation;
 
-    /** @var Db */
-    protected $db;
+    protected Db $db;
 
-    /** @var ServerRequestInterface */
-    protected $request;
+    protected ServerRequestInterface $request;
 
-    /** @var Auth */
-    protected $auth;
+    protected Auth $auth;
 
-    protected $requiredPermission = 'vspheredb/admin';
+    protected string $requiredPermission = 'vspheredb/admin';
 
-    protected $appliedMigrations = false;
+    protected bool $appliedMigrations = false;
 
-    protected $failed = false;
+    protected bool $failed = false;
 
     public function __construct(Db $db, Auth $auth, ServerRequestInterface $request)
     {
@@ -54,9 +52,10 @@ public function __construct(Db $db, Auth $auth, ServerRequestInterface $request)
      *
      * @return bool
      */
-    public function hasAppliedMigrations()
+    public function hasAppliedMigrations(): bool
     {
         $this->ensureAssembled();
+
         return $this->appliedMigrations;
     }
 
@@ -65,13 +64,14 @@ public function hasAppliedMigrations()
      *
      * @return bool
      */
-    public function hasFailed()
+    public function hasFailed(): bool
     {
         $this->ensureAssembled();
+
         return $this->failed;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         try {
             if ($this->auth->hasPermission($this->requiredPermission)) {
@@ -84,15 +84,14 @@ protected function assemble()
         }
     }
 
-    protected function showEventualProblems(Db $db)
+    protected function showEventualProblems(Db $db): void
     {
         $migrations = Db::migrationsForDb($db);
 
         if ($migrations->hasSchema()) {
             if ($migrations->hasPendingMigrations()) {
                 $this->add(Hint::warning($this->translate(
-                    'There are pending Database Schema Migrations. Please ask'
-                    . ' an Administrator to apply them now!'
+                    'There are pending Database Schema Migrations. Please ask an Administrator to apply them now!'
                 )));
             }
         } else {
@@ -103,15 +102,14 @@ protected function showEventualProblems(Db $db)
         }
     }
 
-    protected function showMigrations(Db $db)
+    protected function showMigrations(Db $db): void
     {
         $migrations = Db::migrationsForDb($db);
 
         if ($migrations->hasSchema()) {
             if ($migrations->hasPendingMigrations()) {
                 $this->add(Hint::warning($this->translate(
-                    'There are pending Database Schema Migrations. Please apply'
-                    . ' them now!'
+                    'There are pending Database Schema Migrations. Please apply them now!'
                 )));
                 $this->addForm($migrations);
             }
@@ -137,11 +135,11 @@ protected function showMigrations(Db $db)
         }
     }
 
-    protected function addForm(Migrations $migrations)
+    protected function addForm(Migrations $migrations): void
     {
         $this->add(
             (new ApplyMigrationsForm($migrations))
-                ->on(ApplyMigrationsForm::ON_SUCCESS, function () {
+                ->on(Form::ON_SUBMIT, function () {
                     $this->appliedMigrations = true;
                 })
                 ->handleRequest($this->request)
diff --git a/library/Vspheredb/Web/Widget/CpuAbsoluteUsage.php b/library/Vspheredb/Web/Widget/CpuAbsoluteUsage.php
index 046b1527..029e189d 100644
--- a/library/Vspheredb/Web/Widget/CpuAbsoluteUsage.php
+++ b/library/Vspheredb/Web/Widget/CpuAbsoluteUsage.php
@@ -3,6 +3,7 @@
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
 use Icinga\Module\Vspheredb\Format;
+use ipl\Html\Attributes;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
 use ipl\I18n\Translation;
@@ -13,19 +14,12 @@ class CpuAbsoluteUsage extends BaseHtmlElement
 
     protected $tag = 'div';
 
-    protected $defaultAttributes = [
-        'class' => 'cpu'
-    ];
+    protected $defaultAttributes = ['class' => 'cpu'];
 
-    public function __construct($mhz, $cores = null, $perCore = 2000)
+    public function __construct(int $mhz, ?int $cores = null, int $perCore = 2000)
     {
         $class = null;
         if ($cores !== null) {
-            if (false) {
-                $this->add(Html::tag('span', [
-                    'class' => 'cpu-count'
-                ], sprintf($this->translate('%d CPUs'), $cores)));
-            }
             $usedPerCore = $mhz / $cores;
             if ($usedPerCore / $perCore > 0.7) {
                 $class = 'critical';
@@ -35,16 +29,12 @@ public function __construct($mhz, $cores = null, $perCore = 2000)
         }
 
         if ($class !== null) {
-            $this->addAttributes(['class' => $class]);
+            $this->addAttributes(Attributes::create(['class' => $class]));
         }
         [$value, $unit] = Format::mhzWithSeparateUnit($mhz);
         $this->add([
-            Html::tag('span', [
-                'class' => 'cpu-consumption'
-            ], $value),
-            Html::tag('span', [
-                'class' => 'cpu-unit'
-            ], $unit),
+            Html::tag('span', ['class' => 'cpu-consumption'], $value),
+            Html::tag('span', ['class' => 'cpu-unit'], $unit)
         ])->setSeparator("\n");
     }
 }
diff --git a/library/Vspheredb/Web/Widget/CpuUsage.php b/library/Vspheredb/Web/Widget/CpuUsage.php
index 8e223a40..d446ba56 100644
--- a/library/Vspheredb/Web/Widget/CpuUsage.php
+++ b/library/Vspheredb/Web/Widget/CpuUsage.php
@@ -6,5 +6,9 @@
 
 class CpuUsage extends UsageBar
 {
-    protected $formatter = [Format::class, 'mhz'];
+    public function __construct(int|float|null $used, int|float|null $capacity)
+    {
+        parent::__construct($used, $capacity);
+        $this->formatter = Format::mhz(...);
+    }
 }
diff --git a/library/Vspheredb/Web/Widget/CustomValueDetails.php b/library/Vspheredb/Web/Widget/CustomValueDetails.php
index c861963d..5261758d 100644
--- a/library/Vspheredb/Web/Widget/CustomValueDetails.php
+++ b/library/Vspheredb/Web/Widget/CustomValueDetails.php
@@ -5,34 +5,26 @@
 use ipl\I18n\Translation;
 use gipfl\Web\Table\NameValueTable;
 use Icinga\Module\Vspheredb\Addon\IbmSpectrumProtect;
-use Icinga\Module\Vspheredb\Addon\SimpleBackupTool;
 use Icinga\Module\Vspheredb\Addon\NetBackup;
+use Icinga\Module\Vspheredb\Addon\SimpleBackupTool;
 use Icinga\Module\Vspheredb\Addon\VRangerBackup;
-use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
 use Icinga\Module\Vspheredb\DbObject\CustomValues;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
-use InvalidArgumentException;
 use ipl\Html\HtmlDocument;
 
 class CustomValueDetails extends HtmlDocument
 {
     use Translation;
 
-    /** @var HostSystem|VirtualMachine */
-    protected $object;
+    protected HostSystem|VirtualMachine $object;
 
-    public function __construct(BaseDbObject $object)
+    public function __construct(HostSystem|VirtualMachine $object)
     {
-        if (! $object instanceof HostSystem && ! $object instanceof VirtualMachine) {
-            throw new InvalidArgumentException(
-                'HostSystem or VirtualMachine expected, got ' . \get_class($object)
-            );
-        }
         $this->object = $object;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $object = $this->object;
         $this->prepend(new SubTitle($this->translate('Custom Values'), 'th-list'));
@@ -45,7 +37,7 @@ protected function assemble()
                 'Application'       => 'WebSphere Application Server',
                 'Installation Date' => '2020-01-02',
                 'Cost Center'       => '48145',
-                'Department'        => 'Web Shop',
+                'Department'        => 'Web Shop'
             ]);
         }
         if ($values->isEmpty()) {
@@ -56,15 +48,9 @@ protected function assemble()
         }
     }
 
-    protected function stripBackupToolCustomValues(CustomValues $values)
+    protected function stripBackupToolCustomValues(CustomValues $values): void
     {
-        $tools = [
-            new IbmSpectrumProtect(),
-            new NetBackup(),
-            new VRangerBackup(),
-        ];
-
-        foreach ($tools as $tool) {
+        foreach ([new IbmSpectrumProtect(), new NetBackup(), new VRangerBackup()] as $tool) {
             if ($tool instanceof SimpleBackupTool) {
                 $tool->stripCustomValues($values);
             }
diff --git a/library/Vspheredb/Web/Widget/DatastoreUsage.php b/library/Vspheredb/Web/Widget/DatastoreUsage.php
index a0bfcdd7..3315af8a 100644
--- a/library/Vspheredb/Web/Widget/DatastoreUsage.php
+++ b/library/Vspheredb/Web/Widget/DatastoreUsage.php
@@ -7,9 +7,11 @@
 use Icinga\Module\Vspheredb\DbObject\Datastore;
 use Icinga\Module\Vspheredb\Util;
 use Icinga\Util\Format;
+use ipl\Html\Attributes;
 use ipl\Html\BaseHtmlElement;
 use ipl\I18n\Translation;
 use ipl\Web\Compat\StyleWithNonce;
+use Zend_Db_Adapter_Abstract;
 
 class DatastoreUsage extends BaseHtmlElement
 {
@@ -22,61 +24,52 @@ class DatastoreUsage extends BaseHtmlElement
         'data-base-target' => '_next'
     ];
 
-    /** @var Datastore */
-    protected $datastore;
+    protected Datastore $datastore;
 
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected ?Zend_Db_Adapter_Abstract $db;
 
-    /** @var string */
-    protected $uuid;
+    protected ?string $uuid = null;
 
-    /** @var int */
-    protected $capacity;
+    protected int $capacity;
 
-    /** @var int */
-    protected $uncommitted;
+    protected int $uncommitted;
 
-    protected $gotPercent = 0;
+    protected float $gotPercent = 0;
 
-    protected $baseUrl = 'vspheredb/vm';
+    protected string $baseUrl = 'vspheredb/vm';
 
-    /** @var Link[] Array key is the VirtualMachine id */
-    protected $diskLinks;
+    /** @var ?Link[] Array key is the VirtualMachine id */
+    protected ?array $diskLinks = null;
 
     public function __construct(Datastore $datastore)
     {
-        $this->datastore   = $datastore;
-        $this->uuid        = $datastore->get('uuid');
-        $this->capacity    = (int) $datastore->get('capacity');
+        $this->datastore = $datastore;
+        $this->uuid = $datastore->get('uuid');
+        $this->capacity = (int) $datastore->get('capacity');
         $this->uncommitted = (int) $datastore->get('uncommitted');
         $this->db = $datastore->getDb();
     }
 
-    public function setCapacity($capacity)
+    public function setCapacity(int $capacity): static
     {
         $this->capacity = $capacity;
+
         return $this;
     }
 
-    public function setBaseUrl($url)
+    public function setBaseUrl(string $url): static
     {
         $this->baseUrl = $url;
 
         return $this;
     }
 
-    public function loadAllVmDisks()
+    public function loadAllVmDisks(): static
     {
         $query = $this->db->select()
-            ->from(
-                ['vdu' => 'vm_datastore_usage'],
-                ['o.uuid', 'o.object_name', 'vdu.committed', 'vdu.uncommitted']
-            )->join(
-                ['o' => 'object'],
-                'o.uuid = vdu.vm_uuid',
-                []
-            )->where('vdu.datastore_uuid = ?', $this->datastore->get('uuid'))
+            ->from(['vdu' => 'vm_datastore_usage'], ['o.uuid', 'o.object_name', 'vdu.committed', 'vdu.uncommitted'])
+            ->join(['o' => 'object'], 'o.uuid = vdu.vm_uuid', [])
+            ->where('vdu.datastore_uuid = ?', $this->datastore->get('uuid'))
             // ->order('o.object_name');
             ->order('vdu.committed DESC');
 
@@ -117,7 +110,7 @@ public function loadAllVmDisks()
         return $this;
     }
 
-    public function addDiskFromDbRow($row)
+    public function addDiskFromDbRow(object $row): static
     {
         $info = $this->makeDisk($row);
         if ($info !== null) {
@@ -127,20 +120,19 @@ public function addDiskFromDbRow($row)
         return $this;
     }
 
-    public function addFreeDatastoreSpace()
+    public function addFreeDatastoreSpace(): static
     {
         if ($this->capacity === 0) {
             return $this;
         }
-        $title = sprintf('Free space');
+        $title = 'Free space';
         $free = $this->datastore->get('free_space');
         if ($this->uncommitted < $free) {
             $class = 'free';
         } elseif ($this->uncommitted > 2 * $this->capacity) {
-            $title = sprintf('Committed space');
+            $title = 'Committed space';
             $class = 'free overcommitted-twice';
         } else {
-            $title = sprintf('Free space');
             $class = 'free overcommitted';
         }
 
@@ -154,25 +146,19 @@ public function addFreeDatastoreSpace()
                 ['class' => 'unknown']
             );
         }
-        $this->addVmDisk(
-            $title,
-            $percent,
-            null,
-            ['class' => $class]
-        );
 
-        return $this;
+        return $this->addVmDisk($title, $percent, null, ['class' => $class]);
     }
 
     /**
-     * @param $title
-     * @param $percent
+     * @param string $title
+     * @param float $percent
      * @param ?string $vmUuid
      * @param array $attributes
      *
      * @return $this
      */
-    public function addVmDisk($title, $percent, ?string $vmUuid = null, array $attributes = []): static
+    public function addVmDisk(string $title, float $percent, ?string $vmUuid = null, array $attributes = []): static
     {
         if ($vmUuid) {
             $url = $this->baseUrl;
@@ -195,7 +181,7 @@ public function addVmDisk($title, $percent, ?string $vmUuid = null, array $attri
             ->setModule('vspheredb')
             ->addFor($link, ['width' => sprintf('%.3F%%; ', $percent)]);
 
-        $link->addAttributes($attributes);
+        $link->addAttributes(Attributes::create($attributes));
 
         if ($vmUuid) {
             $alpha = (20 + (crc32(sha1($vmUuid . $this->uuid)) % 60)) / 100;
@@ -203,12 +189,11 @@ public function addVmDisk($title, $percent, ?string $vmUuid = null, array $attri
             $style->addFor($link, ['background-color' => $color]);
             $this->diskLinks[$vmUuid] = $link;
         }
-        $this->add([$link, $style]);
 
-        return $this;
+        return $this->add([$link, $style]);
     }
 
-    protected function makeDisk($dbRow)
+    protected function makeDisk(object $dbRow): ?object
     {
         $size = $dbRow->committed + $dbRow->uncommitted;
         if ($size === 0) {
@@ -216,17 +201,15 @@ protected function makeDisk($dbRow)
         }
 
         $share = (object) [
-            'vm_uuid' => $dbRow->uuid,
-            'name'  => $dbRow->object_name,
-            'size'  => $size,
-            'used'  => $dbRow->committed,
+            'vm_uuid'             => $dbRow->uuid,
+            'name'                => $dbRow->object_name,
+            'size'                => $size,
+            'used'                => $dbRow->committed,
             'used_percent'        => ($dbRow->committed / $size) * 100,
             'datastore_percent'   => ($dbRow->committed / $this->capacity) * 100,
             'uncommitted'         => $dbRow->uncommitted,
-            'uncommitted_percent' => $this->uncommitted > 0
-                ? ($dbRow->uncommitted / $this->uncommitted) * 100
-                : 0,
-            'extra-class' => null,
+            'uncommitted_percent' => $this->uncommitted > 0 ? ($dbRow->uncommitted / $this->uncommitted) * 100 : 0,
+            'extra-class'         => null
         ];
         $share->title = sprintf(
             '%s (%.2f%% of %s) used by %s',
@@ -239,7 +222,7 @@ protected function makeDisk($dbRow)
         return $share;
     }
 
-    protected function bytes($bytes)
+    protected function bytes(int $bytes): string
     {
         return Format::bytes($bytes, Format::STANDARD_IEC);
     }
diff --git a/library/Vspheredb/Web/Widget/DelayedPerfdataRenderer.php b/library/Vspheredb/Web/Widget/DelayedPerfdataRenderer.php
index 3541366a..f72b2300 100644
--- a/library/Vspheredb/Web/Widget/DelayedPerfdataRenderer.php
+++ b/library/Vspheredb/Web/Widget/DelayedPerfdataRenderer.php
@@ -2,40 +2,39 @@
 
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
-use ipl\Html\DeferredText;
 use Icinga\Module\Vspheredb\Web\Table\SimpleColumn;
-use Icinga\Module\Vspheredb\Web\Table\TableColumn;
+use ipl\Html\DeferredText;
+use Zend_Db_Adapter_Abstract;
 
 class DelayedPerfdataRenderer
 {
-    protected $requiredVms = [];
+    protected array $requiredVms = [];
 
-    protected $perf;
+    protected ?array $perf = null;
 
-    protected $counters = [
+    protected array $counters = [
         526 => 'net.bytesRx',
         527 => 'net.bytesRx',
         171 => 'virtualDisk.numberReadAveraged',
-        172 => 'virtualDisk.numberWriteAveraged',
+        172 => 'virtualDisk.numberWriteAveraged'
     ];
 
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
 
-    public function __construct(\Zend_Db_Adapter_Abstract $db)
+    public function __construct(Zend_Db_Adapter_Abstract $db)
     {
         $this->db = $db;
     }
 
-    public function requireVm($uuid)
+    public function requireVm(string $uuid): void
     {
         $this->requiredVms[] = $uuid;
     }
 
     /**
-     * @return TableColumn
+     * @return SimpleColumn
      */
-    public function getDiskColumn()
+    public function getDiskColumn(): SimpleColumn
     {
         return (new SimpleColumn('disk_io_perf', '5x5min Disk I/O', 'o.uuid'))
             ->setRenderer(function ($row) {
@@ -46,9 +45,9 @@ public function getDiskColumn()
     }
 
     /**
-     * @return TableColumn
+     * @return SimpleColumn
      */
-    public function getNetColumn()
+    public function getNetColumn(): SimpleColumn
     {
         return (new SimpleColumn('network_io_perf', 'Network I/O (perf)', 'o.uuid'))
             ->setRenderer(function ($row) {
@@ -59,9 +58,9 @@ public function getNetColumn()
     }
 
     /**
-     * @return TableColumn
+     * @return SimpleColumn
      */
-    public function getCurrentNetColumn()
+    public function getCurrentNetColumn(): SimpleColumn
     {
         return (new SimpleColumn('network_io', 'Network I/O', 'o.uuid'))
             ->setRenderer(function ($row) {
@@ -72,9 +71,9 @@ public function getCurrentNetColumn()
     }
 
     /**
-     * @return TableColumn
+     * @return SimpleColumn
      */
-    public function getCurrentDiskColumn()
+    public function getCurrentDiskColumn(): SimpleColumn
     {
         return (new SimpleColumn('disk_io', 'Disk I/O', 'o.uuid'))
             ->setRenderer(function ($row) {
@@ -84,25 +83,23 @@ public function getCurrentDiskColumn()
             });
     }
 
-    protected function formatMicroSeconds($num)
+    protected function formatMicroSeconds(int $num): string
     {
         if ($num > 500) {
             return sprintf('%0.2Fms', $num / 1000);
-        } else {
-            return sprintf('%dµs', $num);
         }
+
+        return sprintf('%dµs', $num);
     }
 
-    protected function formatKiloBytesPerSecond($num)
+    protected function formatKiloBytesPerSecond(int $num): string
     {
         $num *= 8;
-        if ($num > 500000) {
-            return sprintf('%0.2F Gbit/s', $num / 1024 / 1024);
-        } elseif ($num > 500) {
-            return sprintf('%0.2F Mbit/s', $num / 1024);
-        } else {
-            return sprintf('%0.2F Kbit/s', $num);
-        }
+        return match (true) {
+            $num > 500000 => sprintf('%0.2F Gbit/s', $num / 1024 / 1024),
+            $num > 500    => sprintf('%0.2F Mbit/s', $num / 1024),
+            default       => sprintf('%0.2F Kbit/s', $num)
+        };
     }
 
     /**
@@ -118,16 +115,9 @@ protected function createKbInOut(string $uuid, string $instance, int $c1, int $c
         return DeferredText::create(function () use ($uuid, $instance, $c1, $c2) {
             $in = explode(',', $this->getVmValues($uuid, $instance, $c1));
             $out = explode(',', $this->getVmValues($uuid, $instance, $c2));
-            if ($in[0] === '') {
-                $in = '-';
-            } else {
-                $in = $this->formatKiloBytesPerSecond(array_pop($in));
-            }
-            if ($out[0] === '') {
-                $out = '-';
-            } else {
-                $out = $this->formatKiloBytesPerSecond(array_pop($out));
-            }
+
+            $in = $in[0] === '' ? '-' : $this->formatKiloBytesPerSecond(array_pop($in));
+            $out = $out[0] === '' ? '-' : $this->formatKiloBytesPerSecond(array_pop($out));
 
             return sprintf('%s / %s', $in, $out);
         })->setEscaped();
@@ -160,9 +150,7 @@ protected function createPerfInOut(string $uuid, string $instance, int $c1, int
      */
     protected function getVmValues(string $name, string $instance, int $counter): ?array
     {
-        if ($this->perf === null) {
-            $this->perf = $this->fetchPerf();
-        }
+        $this->perf ??= $this->fetchPerf();
 
         if (
             array_key_exists($name, $this->perf)
@@ -170,12 +158,12 @@ protected function getVmValues(string $name, string $instance, int $counter): ?a
             && array_key_exists($counter, $this->perf[$name][$instance])
         ) {
             return $this->perf[$name][$instance][$counter];
-        } else {
-            return null;
         }
+
+        return null;
     }
 
-    protected function fetchPerf()
+    protected function fetchPerf(): array
     {
         $db = $this->db;
 
@@ -184,16 +172,18 @@ protected function fetchPerf()
                 "COALESCE(value_minus3, '0')",
                 "COALESCE(value_minus2, '0')",
                 "COALESCE(value_minus1, '0')",
-                'value_last',
+                'value_last'
             ]) . ')';
 
-        $query = $db->select()->from('counter_300x5', [
-            'name' => 'object_uuid',
-            'instance',
-            'counter_key',
-            'value' => $values,
-            'value_last'
-        ])->where('object_uuid IN (?)', $this->requiredVms)
+        $query = $db->select()
+            ->from('counter_300x5', [
+                'name'  => 'object_uuid',
+                'instance',
+                'counter_key',
+                'value' => $values,
+                'value_last'
+            ])
+            ->where('object_uuid IN (?)', $this->requiredVms)
             ->where('instance IN (?)', ['', 'scsi0:0'])
             ->where('counter_key IN (?)', array_keys($this->counters));
 
diff --git a/library/Vspheredb/Web/Widget/Documentation.php b/library/Vspheredb/Web/Widget/Documentation.php
index 47bdee96..2c61cb5a 100644
--- a/library/Vspheredb/Web/Widget/Documentation.php
+++ b/library/Vspheredb/Web/Widget/Documentation.php
@@ -20,10 +20,11 @@ class Documentation
 
     protected const PUBLIC_URL_MAP = [
         'vspheredb' => 'icinga-vsphere-integration',
-        'director'  => 'icinga-director',
+        'director'  => 'icinga-director'
     ];
 
     protected ApplicationBootstrap $app;
+
     protected Auth $auth;
 
     // true links to GitHub, false to icinga.com
@@ -36,40 +37,36 @@ public function __construct(ApplicationBootstrap $app, Auth $auth)
     }
 
     /**
-     * @param $label
+     * @param string $label
      * @param string $module
-     * @param $chapter
-     * @param $title
+     * @param string $chapter
+     * @param ?string $title
      *
      * @return Link|HtmlElement
      */
-    public static function link($label, string $module, $chapter, $title = null): Link|HtmlElement
+    public static function link(string $label, string $module, string $chapter, ?string $title = null): Link|HtmlElement
     {
-        $doc = new static(Icinga::app(), Auth::getInstance());
-
-        return $doc->getModuleLink($label, $module, $chapter, $title);
+        return (new static(Icinga::app(), Auth::getInstance()))->getModuleLink($label, $module, $chapter, $title);
     }
 
     /**
-     * @param $label
+     * @param string $label
      * @param string $module
-     * @param $chapter
-     * @param $title
+     * @param string $chapter
+     * @param ?string $title
      *
      * @return Link|HtmlElement
      */
-    public function getModuleLink($label, string $module, $chapter, $title = null): Link|HtmlElement
-    {
+    public function getModuleLink(
+        string $label,
+        string $module,
+        string $chapter,
+        ?string $title = null
+    ): Link|HtmlElement {
         if ($title !== null) {
-            $title = sprintf(
-                $this->translate('Click to read our documentation: %s'),
-                $title
-            );
+            $title = sprintf($this->translate('Click to read our documentation: %s'), $title);
         }
-        $baseParams = [
-            'class' => 'icon-book',
-            'title' => $title,
-        ];
+        $baseParams = ['class' => 'icon-book', 'title' => $title];
         if ($this->hasAccessToDocumentationModule()) {
             return Link::create(
                 $label,
@@ -79,22 +76,19 @@ public function getModuleLink($label, string $module, $chapter, $title = null):
             );
         }
 
-        $baseParams = [
-            'target' => '_blank',
-            'rel'    => 'noreferrer',
-        ];
+        $baseParams = ['target' => '_blank', 'rel' => 'noreferrer'];
         if ($this->linkToGitHub || ! isset(self::PUBLIC_URL_MAP[$module])) {
-            return Html::tag('a', [
-                    'href' => $this->githubDocumentationUrl($module, $chapter),
-                ] + $baseParams, $label);
+            return Html::tag('a', ['href' => $this->githubDocumentationUrl($module, $chapter)] + $baseParams, $label);
         }
 
-        return Html::tag('a', [
-                'href' => $this->icingaDocumentationUrl(self::PUBLIC_URL_MAP[$module], $chapter),
-            ] + $baseParams, $label);
+        return Html::tag(
+            'a',
+            ['href' => $this->icingaDocumentationUrl(self::PUBLIC_URL_MAP[$module], $chapter)] + $baseParams,
+            $label
+        );
     }
 
-    protected function getModuleDocumentationUrl($moduleName, $chapter): string
+    protected function getModuleDocumentationUrl(string $moduleName, string $chapter): string
     {
         return sprintf(
             'doc/module/%s/chapter/%s',
@@ -103,7 +97,7 @@ protected function getModuleDocumentationUrl($moduleName, $chapter): string
         );
     }
 
-    protected function githubDocumentationUrl($module, $chapter): string
+    protected function githubDocumentationUrl(string $module, string $chapter): string
     {
         return sprintf(
             "https://github.com/Icinga/icingaweb2-module-%s/blob/master/doc/%s.md",
@@ -112,7 +106,7 @@ protected function githubDocumentationUrl($module, $chapter): string
         );
     }
 
-    protected function icingaDocumentationUrl($module, $chapter): string
+    protected function icingaDocumentationUrl(string $module, string $chapter): string
     {
         return sprintf(
             'https://icinga.com/docs/%s/latest/doc/%s/',
@@ -123,7 +117,6 @@ protected function icingaDocumentationUrl($module, $chapter): string
 
     protected function hasAccessToDocumentationModule(): bool
     {
-        return $this->app->getModuleManager()->hasLoaded('doc')
-            && $this->auth->hasPermission('module/doc');
+        return $this->app->getModuleManager()->hasLoaded('doc') && $this->auth->hasPermission('module/doc');
     }
 }
diff --git a/library/Vspheredb/Web/Widget/GrafanaVmPanel.php b/library/Vspheredb/Web/Widget/GrafanaVmPanel.php
index df3342a3..1198ca2e 100644
--- a/library/Vspheredb/Web/Widget/GrafanaVmPanel.php
+++ b/library/Vspheredb/Web/Widget/GrafanaVmPanel.php
@@ -13,17 +13,14 @@
  */
 class GrafanaVmPanel extends HtmlDocument
 {
-    /** @var ManagedObject */
-    protected $object;
+    protected ManagedObject $object;
 
-    /** @var int */
-    protected $panels;
+    /** @var int[] */
+    protected array $panels;
 
-    /** @var string|null */
-    protected $interface;
+    protected ?string $interface;
 
-    /** @var string|null */
-    protected $disk;
+    protected ?string $disk;
 
     /**
      * @param ManagedObject $object
@@ -31,7 +28,7 @@ class GrafanaVmPanel extends HtmlDocument
      * @param ?string $interface
      * @param ?string $disk
      */
-    public function __construct(ManagedObject $object, array $panels, $interface = 'All', $disk = 'All')
+    public function __construct(ManagedObject $object, array $panels, ?string $interface = 'All', ?string $disk = 'All')
     {
         $this->object = $object;
         $this->panels = $panels;
@@ -39,7 +36,7 @@ public function __construct(ManagedObject $object, array $panels, $interface = '
         $this->disk = $disk;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $width = floor(100 / count($this->panels));
         foreach ($this->panels as $id) {
@@ -47,21 +44,18 @@ protected function assemble()
                 'src' => $this->panelUrl($id),
                 'width' => $width . '%',
                 'height' => 200,
-                'frameborder' => 0,
+                'frameborder' => 0
             ]));
         }
     }
 
-    protected function panelUrl($panelId)
+    protected function panelUrl(int $panelId): string
     {
         // &from=1636834148559&to=1636838149732
         $orgId = 1;
         $dsName = 'vSphereDB';
         $dashboard = 'Icinga-vSphereDB-VirtualMachineDetails';
-        $url = sprintf(
-            'https://grafana.example.com:3000/d-solo/%s/virtual-machine-details',
-            $dashboard
-        );
+        $url = sprintf('https://grafana.example.com:3000/d-solo/%s/virtual-machine-details', $dashboard);
 
         $params = [
             'orgId' => $orgId,
@@ -72,7 +66,7 @@ protected function panelUrl($panelId)
             'theme' => 'light',
             'panelId' => $panelId,
             'from' => 1636834044566,
-            'to'   => 1636843374647,
+            'to'   => 1636843374647
         ];
 
         return $url . '?' . build_query($params);
diff --git a/library/Vspheredb/Web/Widget/GuestToolsStatusRenderer.php b/library/Vspheredb/Web/Widget/GuestToolsStatusRenderer.php
index 4e9ca26a..455679de 100644
--- a/library/Vspheredb/Web/Widget/GuestToolsStatusRenderer.php
+++ b/library/Vspheredb/Web/Widget/GuestToolsStatusRenderer.php
@@ -10,38 +10,33 @@ class GuestToolsStatusRenderer extends Html
 {
     use Translation;
 
-    public function __invoke($state)
+    public function __invoke($state): Icon
     {
         if (is_object($state)) {
             $state = $state->guest_tools_status;
         }
-        switch ($state) {
-            case 'toolsNotInstalled':
-                return Icon::create('block', [
-                    'class' => 'red',
-                    'title' => $this->translate('Guest Tools are NOT installed'),
-                ]);
-            case 'toolsNotRunning':
-                return Icon::create('warning-empty', [
-                    'class' => 'red',
-                    'title' => $this->translate('Guest Tools are NOT running'),
-                ]);
-            case 'toolsOld':
-                return Icon::create('thumbs-down', [
-                    'class' => 'yellow',
-                    'title' => $this->translate('Guest Tools are outdated'),
-                ]);
-            case 'toolsOk':
-                return Icon::create('ok', [
-                    'class' => 'green',
-                    'title' => $this->translate('Guest Tools are up to date and running'),
-                ]);
-            case null:
-            default:
-                return Icon::create('help', [
-                    'class' => 'gray',
-                    'title' => $this->translate('Guest Tools status is now known'),
-                ]);
-        }
+
+        return match ($state) {
+            'toolsNotInstalled' => Icon::create('block', [
+                'class' => 'red',
+                'title' => $this->translate('Guest Tools are NOT installed')
+            ]),
+            'toolsNotRunning'   => Icon::create('warning-empty', [
+                'class' => 'red',
+                'title' => $this->translate('Guest Tools are NOT running')
+            ]),
+            'toolsOld'          => Icon::create('thumbs-down', [
+                'class' => 'yellow',
+                'title' => $this->translate('Guest Tools are outdated')
+            ]),
+            'toolsOk'           => Icon::create('ok', [
+                'class' => 'green',
+                'title' => $this->translate('Guest Tools are up to date and running')
+            ]),
+            default             => Icon::create('help', [
+                'class' => 'gray',
+                'title' => $this->translate('Guest Tools status is now known')
+            ])
+        };
     }
 }
diff --git a/library/Vspheredb/Web/Widget/HostHeader.php b/library/Vspheredb/Web/Widget/HostHeader.php
index d1f728c8..827286b3 100644
--- a/library/Vspheredb/Web/Widget/HostHeader.php
+++ b/library/Vspheredb/Web/Widget/HostHeader.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
 use Icinga\Module\Vspheredb\DbObject\HostQuickStats;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
@@ -11,20 +12,15 @@
 
 class HostHeader extends BaseHtmlElement
 {
-    /** @var HostSystem */
-    protected $host;
+    protected HostSystem $host;
 
-    /** @var HtmlDocument */
-    protected $icons;
+    protected ?HtmlDocument $icons = null;
 
     protected $tag = 'div';
 
-    protected $defaultAttributes = [
-        'class' => 'host-header'
-    ];
+    protected $defaultAttributes = ['class' => 'host-header'];
 
-    /** @var HostQuickStats */
-    protected $quickStats;
+    protected HostQuickStats $quickStats;
 
     public function __construct(HostSystem $host, HostQuickStats $quickStats)
     {
@@ -32,24 +28,20 @@ public function __construct(HostSystem $host, HostQuickStats $quickStats)
         $this->quickStats = $quickStats;
     }
 
-    public function getIcons()
+    public function getIcons(): HtmlDocument
     {
-        if ($this->icons === null) {
-            $powerStateRenderer = new PowerStateRenderer();
-            $overallStatusRenderer = new OverallStatusRenderer();
-            $this->icons = (new HtmlDocument())->add([
-                $overallStatusRenderer($this->host->object()->get('overall_status')),
-                $powerStateRenderer($this->host->get('runtime_power_state')),
-            ]);
-        }
+        $this->icons ??= (new HtmlDocument())->add([
+            (new OverallStatusRenderer())($this->host->object()->get('overall_status')),
+            (new PowerStateRenderer())($this->host->get('runtime_power_state'))
+        ]);
 
         return $this->icons;
     }
 
     /**
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws NotFoundError
      */
-    protected function assemble()
+    protected function assemble(): void
     {
         $host = $this->host;
         $host->object()->set('object_name', Anonymizer::anonymizeString($host->object()->get('object_name')));
@@ -62,14 +54,7 @@ protected function assemble()
             $this->quickStats->get('overall_memory_usage_mb'),
             $host->get('hardware_memory_size_mb')
         );
-        $title = Html::tag('h1', [
-            $host->object()->get('object_name'),
-            $this->getIcons()
-        ]);
-        $this->add([
-            $cpu,
-            $title,
-            $mem
-        ]);
+        $title = Html::tag('h1', [$host->object()->get('object_name'), $this->getIcons()]);
+        $this->add([$cpu, $title, $mem]);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/HostMonitoringInfo.php b/library/Vspheredb/Web/Widget/HostMonitoringInfo.php
index 905b9299..5e048240 100644
--- a/library/Vspheredb/Web/Widget/HostMonitoringInfo.php
+++ b/library/Vspheredb/Web/Widget/HostMonitoringInfo.php
@@ -8,7 +8,6 @@
 use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
-use ipl\Html\Html;
 use ipl\Html\HtmlDocument;
 use ipl\I18n\Translation;
 
@@ -16,14 +15,11 @@ class HostMonitoringInfo extends HtmlDocument
 {
     use Translation;
 
-    /** @var HostSystem */
-    protected $host;
+    protected HostSystem $host;
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
-    /** @var mixed */
-    protected $info;
+    protected false|array|null $info = null;
 
     /**
      * HostVirtualizationInfoTable constructor.
@@ -36,7 +32,7 @@ public function __construct(HostSystem $host)
         $this->vCenter = VCenter::load($host->get('vcenter_uuid'), $host->getConnection());
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         if ($info = $this->getInfo()) {
             $this->prepend(new SubTitle($this->translate('Monitoring'), 'binoculars'));
@@ -44,28 +40,24 @@ protected function assemble()
         }
     }
 
-    public function hasInfo()
+    public function hasInfo(): bool
     {
         return $this->getInfo() !== false;
     }
 
-    protected function getInfo()
+    protected function getInfo(): false|array
     {
-        if ($this->info === null) {
-            $this->info = $this->prepareInfo();
-        }
+        $this->info ??= $this->prepareInfo();
 
         return $this->info;
     }
 
     /**
-     * @return array|false
+     * @return false|array
      */
-    protected function prepareInfo()
+    protected function prepareInfo(): false|array
     {
-        $host = $this->host;
-        $name = $host->get('host_name');
-        $statusRenderer = new IcingaHostStatusRenderer();
+        $name = $this->host->get('host_name');
 
         try {
             // $monitoring = MonitoringConnection::eventuallyLoadForVCenter($this->vCenter);
@@ -74,7 +66,7 @@ protected function prepareInfo()
                 $monitoringState = $monitoring->getHostState($name);
                 return [
                     // TODO: is_acknowledged, is_in_downtime
-                    $statusRenderer($monitoringState->current_state),
+                    (new IcingaHostStatusRenderer())($monitoringState->current_state),
                     ' ',
                     $monitoringState->output,
                     ' ',
@@ -85,16 +77,11 @@ protected function prepareInfo()
                         ['class' => 'icon-right-small']
                     )
                 ];
-            } else {
-                return false;
             }
+
+            return false;
         } catch (Exception $e) {
-            return [
-                Hint::error(
-                    $this->translate('Unable to check monitoring state: %s'),
-                    $e->getMessage()
-                )
-            ];
+            return [Hint::error($this->translate('Unable to check monitoring state: %s'), $e->getMessage())];
         }
     }
 }
diff --git a/library/Vspheredb/Web/Widget/IcingaHostStatusRenderer.php b/library/Vspheredb/Web/Widget/IcingaHostStatusRenderer.php
index 5a80a670..70da38b5 100644
--- a/library/Vspheredb/Web/Widget/IcingaHostStatusRenderer.php
+++ b/library/Vspheredb/Web/Widget/IcingaHostStatusRenderer.php
@@ -10,7 +10,7 @@ class IcingaHostStatusRenderer extends Html
 {
     use Translation;
 
-    public function __invoke($state)
+    public function __invoke($state): Icon
     {
         if (is_object($state)) {
             $state = $state->overall_status;
@@ -18,7 +18,7 @@ public function __invoke($state)
 
         return Icon::create('eye', [
             'title' => $this->getStatusDescription($state),
-            'class' => [ 'state', $state ]
+            'class' => ['state', $state]
         ]);
     }
 
@@ -29,13 +29,11 @@ public function __invoke($state)
      */
     protected function getStatusDescription(string $status): string
     {
-        $descriptions = [
-            'UP'   => $this->translate('This system is up'),
+        return match ($status) {
+            'UP'          => $this->translate('This system is up'),
             'DOWN'        => $this->translate('This system is down'),
             'UNREACHABLE' => $this->translate('Unreachable - another device might be responsible for this outage'),
-            'PENDING'     => $this->translate('Pending - this host has never been checked'),
-        ];
-
-        return $descriptions[$status];
+            'PENDING'     => $this->translate('Pending - this host has never been checked')
+        };
     }
 }
diff --git a/library/Vspheredb/Web/Widget/Link/Html5UiLink.php b/library/Vspheredb/Web/Widget/Link/Html5UiLink.php
index 874aa7af..53857776 100644
--- a/library/Vspheredb/Web/Widget/Link/Html5UiLink.php
+++ b/library/Vspheredb/Web/Widget/Link/Html5UiLink.php
@@ -19,30 +19,32 @@ class Html5UiLink extends BaseHtmlElement
     use Translation;
 
     public const QUERYSTRING = '/ui/#?extensionId=%s&objectId=%s&navigator=%s';
+
     public const QUERYSTRING_LEGACY = [
         HostSystem::class     => '/ui/#/host/%s',
-        VirtualMachine::class => '/ui/#/host/vms/%s',
+        VirtualMachine::class => '/ui/#/host/vms/%s'
     ];
+
     public const OBJECT_TYPES = [
         HostSystem::class     => 'HostSystem',
-        VirtualMachine::class => 'VirtualMachine',
+        VirtualMachine::class => 'VirtualMachine'
     ];
 
     // left-hand tree view:
     public const NAVIGATOR = [
         HostSystem::class     => 'vsphere.core.viTree.hostsAndClustersView',
-        VirtualMachine::class => 'vsphere.core.viTree.vmsAndTemplatesView',
+        VirtualMachine::class => 'vsphere.core.viTree.vmsAndTemplatesView'
     ];
+
     public const EXTENSION = [
         // Choose main detail view:
         //  $extension = 'vsphere.core.vm.monitor'; // Shows 'Monitor' Tab
         // $extension = 'vsphere.core.inventory.serverObjectViewsExtension';
         HostSystem::class     => 'vsphere.core.host.summary',
-        VirtualMachine::class => 'vsphere.core.vm.summary',
+        VirtualMachine::class => 'vsphere.core.vm.summary'
     ];
 
-    /** @var BaseDbObject */
-    protected $object;
+    protected ?BaseDbObject $object = null;
 
     public $tag = 'a';
 
@@ -55,34 +57,28 @@ public function __construct(VCenter $vCenter, BaseDbObject $object, $label)
         $this->setAttribute('target', '_blank'); // To keep the session
     }
 
-    protected static function prepareUrl(VCenter $vCenter, BaseDbObject $object)
+    protected static function prepareUrl(VCenter $vCenter, BaseDbObject $object): string
     {
-        $url = self::prepareBaseUrl($vCenter);
-        if (self::isLegacy($vCenter)) {
-            $url .= self::linkLegacy($object);
-        } else {
-            $url .= self::linkHtml5Ui($object, $vCenter);
-        }
-
-        return $url;
+        return self::prepareBaseUrl($vCenter)
+            . (self::isLegacy($vCenter) ? self::linkLegacy($object) : self::linkHtml5Ui($object, $vCenter));
     }
 
-    protected static function prepareBaseUrl(VCenter $vCenter)
+    protected static function prepareBaseUrl(VCenter $vCenter): string
     {
         return 'https://' . $vCenter->getFirstServer(false)->get('host');
     }
 
-    protected static function isLegacy(VCenter $vCenter)
+    protected static function isLegacy(VCenter $vCenter): bool
     {
         return version_compare($vCenter->get('version'), '6.7.0', '<');
     }
 
-    protected static function linkLegacy(BaseDbObject $object)
+    protected static function linkLegacy(BaseDbObject $object): string
     {
         return sprintf(self::pick(self::QUERYSTRING_LEGACY, $object), rawurlencode($object->object()->get('moref')));
     }
 
-    protected static function linkHtml5Ui(BaseDbObject $object, VCenter $vCenter)
+    protected static function linkHtml5Ui(BaseDbObject $object, VCenter $vCenter): string
     {
         return sprintf(
             self::QUERYSTRING,
@@ -92,7 +88,7 @@ protected static function linkHtml5Ui(BaseDbObject $object, VCenter $vCenter)
         );
     }
 
-    protected static function prepareV7ObjectId(VCenter $vCenter, BaseDbObject $object)
+    protected static function prepareV7ObjectId(VCenter $vCenter, BaseDbObject $object): string
     {
         return sprintf(
             'urn:vmomi:%s:%s:%s',
@@ -102,12 +98,12 @@ protected static function prepareV7ObjectId(VCenter $vCenter, BaseDbObject $obje
         );
     }
 
-    protected static function moref(BaseDbObject $object)
+    protected static function moref(BaseDbObject $object): ?string
     {
         return $object->object()->get('moref');
     }
 
-    protected static function pick(array $list, BaseDbObject $object)
+    protected static function pick(array $list, BaseDbObject $object): mixed
     {
         $class = get_class($object);
         if (isset($list[$class])) {
@@ -117,10 +113,7 @@ protected static function pick(array $list, BaseDbObject $object)
         throw new RuntimeException("Unable to generate HTML5 UI link for $class");
     }
 
-    /**
-     * @throws \Icinga\Exception\NotFoundError
-     */
-    protected function assemble()
+    protected function assemble(): void
     {
     }
 }
diff --git a/library/Vspheredb/Web/Widget/Link/KnowledgeBaseLink.php b/library/Vspheredb/Web/Widget/Link/KnowledgeBaseLink.php
index a1b0d0e2..eb696abf 100644
--- a/library/Vspheredb/Web/Widget/Link/KnowledgeBaseLink.php
+++ b/library/Vspheredb/Web/Widget/Link/KnowledgeBaseLink.php
@@ -13,19 +13,14 @@ class KnowledgeBaseLink extends BaseHtmlElement
 
     protected $defaultAttributes = [
         'target' => '_blank',
-        'class'  => 'vmware_kb_link',
+        'class'  => 'vmware_kb_link'
     ];
 
-    public function __construct($id, $title = null, $label = null)
+    public function __construct(int $id, ?string $title = null, ?string $label = null)
     {
         $this->id = $id;
-        if ($label === null) {
-            $this->setContent("KB $id");
-        } else {
-            $this->setContent($label);
-        }
-
+        $this->setContent($label ?? "KB $id");
         $this->setAttribute('title', $title);
-        $this->setAttribute('href', 'https://kb.vmware.com/s/article/' . \rawurlencode($id));
+        $this->setAttribute('href', 'https://kb.vmware.com/s/article/' . rawurlencode($id));
     }
 }
diff --git a/library/Vspheredb/Web/Widget/Link/MobLink.php b/library/Vspheredb/Web/Widget/Link/MobLink.php
index 27f21c05..99cbc11c 100644
--- a/library/Vspheredb/Web/Widget/Link/MobLink.php
+++ b/library/Vspheredb/Web/Widget/Link/MobLink.php
@@ -7,6 +7,7 @@
 use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
 use Icinga\Module\Vspheredb\DbObject\VCenter;
 use Icinga\Module\Vspheredb\DbObject\VCenterServer;
+use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
 use ipl\Html\HtmlDocument;
 use ipl\I18n\Translation;
@@ -18,43 +19,34 @@ class MobLink extends HtmlDocument
 {
     use Translation;
 
-    protected $vCenter;
+    protected VCenter $vCenter;
 
-    protected $label;
+    protected string $label;
 
-    protected $moRef;
+    protected ?string $moRef = null;
 
-    public function __construct(VCenter $vCenter, ?BaseDbObject $object = null, $label = null)
+    public function __construct(VCenter $vCenter, ?BaseDbObject $object = null, ?string $label = null)
     {
         $this->vCenter = $vCenter;
         if ($object) {
             $this->moRef = $object->object()->get('moref');
         }
-        if ($label === null) {
-            if ($this->moRef) {
-                $this->label = $this->moRef;
-            } else {
-                $this->label = 'MOB';
-            }
-        } else {
-            $this->label = $label;
-        }
+
+        $this->label = $label ?? ($this->moRef ?: 'MOB');
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         try {
             $server = $this->vCenter->getFirstServer(false);
-            if ($this->moRef) {
-                $this->add($this->createObjectLink($server, $this->moRef, $this->label));
-            } else {
-                $this->add($this->createBaseLink($server, $this->label));
-            }
-        } catch (NotFoundError $e) {
+            $this->add(
+                $this->moRef
+                    ? $this->createObjectLink($server, $this->moRef, $this->label)
+                    : $this->createBaseLink($server, $this->label)
+            );
+        } catch (NotFoundError) {
             $this->add([
-                Icon::create('warning-empty', [
-                    'class' => 'red'
-                ]),
+                Icon::create('warning-empty', ['class' => 'red']),
                 ' ',
                 $this->translate('No related vServer has been configured')
             ]);
@@ -65,39 +57,32 @@ protected function assemble()
      * @param VCenterServer $server
      * @param string $moRef
      * @param string $label
-     * @return \ipl\Html\BaseHtmlElement
+     *
+     * @return BaseHtmlElement
      */
-    protected function createObjectLink(VCenterServer $server, $moRef, $label)
+    protected function createObjectLink(VCenterServer $server, string $moRef, string $label): BaseHtmlElement
     {
         return Html::tag('a', [
-            'href' => sprintf(
-                'https://%s/mob/?moid=%s',
-                $server->get('host'),
-                rawurlencode($moRef)
-            ),
+            'href'   => sprintf('https://%s/mob/?moid=%s', $server->get('host'), rawurlencode($moRef)),
             'target' => '_blank',
-            'title' => sprintf(
-                $this->translate('Show "%s" in the Managed Object Browser (MOB)'),
-                $moRef
-            ),
-            'class' => 'icon-eye',
+            'title'  => sprintf($this->translate('Show "%s" in the Managed Object Browser (MOB)'), $moRef),
+            'class'  => 'icon-eye'
         ], $label);
     }
 
     /**
      * @param VCenterServer $server
      * @param string $label
-     * @return \ipl\Html\BaseHtmlElement
+     *
+     * @return BaseHtmlElement
      */
-    protected function createBaseLink(VCenterServer $server, $label)
+    protected function createBaseLink(VCenterServer $server, $label): BaseHtmlElement
     {
         return Html::tag('a', [
-            'href' => sprintf('https://%s/mob/', $server->get('host')),
+            'href'   => sprintf('https://%s/mob/', $server->get('host')),
             'target' => '_blank',
-            'title' => sprintf(
-                $this->translate('Open the Managed Object Browser (MOB)')
-            ),
-            'class' => 'icon-eye',
+            'title'  => sprintf($this->translate('Open the Managed Object Browser (MOB)')),
+            'class'  => 'icon-eye'
         ], $label);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/Link/VmrcLink.php b/library/Vspheredb/Web/Widget/Link/VmrcLink.php
index 1faf3aca..c62aa239 100644
--- a/library/Vspheredb/Web/Widget/Link/VmrcLink.php
+++ b/library/Vspheredb/Web/Widget/Link/VmrcLink.php
@@ -14,43 +14,32 @@ class VmrcLink extends HtmlDocument
 {
     use Translation;
 
-    protected $vCenter;
+    protected VCenter $vCenter;
 
-    protected $label;
+    protected ?string $label;
 
-    protected $moRef;
+    protected ?string $moRef;
 
-    public function __construct(VCenter $vCenter, VirtualMachine $vm, $label = null)
+    public function __construct(VCenter $vCenter, VirtualMachine $vm, ?string $label = null)
     {
         $this->vCenter = $vCenter;
-        if ($label === null) {
-            $this->label = $vm->object()->get('object_name');
-        } else {
-            $this->label = $label;
-        }
-
+        $this->label = $label ?? $vm->object()->get('object_name');
         $this->moRef = $vm->object()->get('moref');
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         try {
             $server = $this->vCenter->getFirstServer(false);
             $this->add(Html::tag('a', [
-                'href' => sprintf(
-                    'vmrc://%s/?moid=%s',
-                    $server->get('host'),
-                    \rawurlencode($this->moRef)
-                ),
+                'href'   => sprintf('vmrc://%s/?moid=%s', $server->get('host'), rawurlencode($this->moRef)),
                 'target' => '_self',
-                'title' => $this->translate('Open VMware Remote Console (VMRC)'),
-                'class' => 'icon-host',
+                'title'  => $this->translate('Open VMware Remote Console (VMRC)'),
+                'class'  => 'icon-host'
             ], $this->label));
-        } catch (NotFoundError $e) {
+        } catch (NotFoundError) {
             $this->add([
-                Icon::create('warning-empty', [
-                    'class' => 'red'
-                ]),
+                Icon::create('warning-empty', ['class' => 'red']),
                 ' ',
                 $this->translate('No related vServer has been configured')
             ]);
diff --git a/library/Vspheredb/Web/Widget/MemoryUsage.php b/library/Vspheredb/Web/Widget/MemoryUsage.php
index 7d11bcee..bdeb61bc 100644
--- a/library/Vspheredb/Web/Widget/MemoryUsage.php
+++ b/library/Vspheredb/Web/Widget/MemoryUsage.php
@@ -7,38 +7,36 @@
 
 class MemoryUsage extends UsageBar
 {
-    /** @var int */
-    protected $usedHost;
+    protected int|float|null $usedHost;
 
-    protected $colors = [
+    protected array $colors = [
         'used' => 'rgba(0, 149, 191, 0.75)',
-        'host' => 'rgba(160, 200, 211, 0.75)',
+        'host' => 'rgba(160, 200, 211, 0.75)'
     ];
 
-    protected $formatter = [Format::class, 'mBytes'];
-
-    public function __construct($usedMb, $capacityMb, $usedHostMb = null)
+    public function __construct(int|float|null $usedMb, int|float|null $capacityMb, int|float|null $usedHostMb = null)
     {
         parent::__construct($usedMb, $capacityMb);
         $this->usedHost = $usedHostMb;
+        $this->formatter = Format::mBytes(...);
     }
 
-    protected function getLabelUsed()
+    protected function getLabelUsed(): string
     {
         if ($this->usedHost === null) {
             return parent::getLabelUsed();
-        } else {
-            return sprintf(
-                '%s: %s (%s: %s)',
-                $this->translate('Active'),
-                $this->format($this->used),
-                $this->translate('Host'),
-                $this->format($this->usedHost)
-            );
         }
+
+        return sprintf(
+            '%s: %s (%s: %s)',
+            $this->translate('Active'),
+            $this->format($this->used),
+            $this->translate('Host'),
+            $this->format($this->usedHost)
+        );
     }
 
-    protected function assembleBar(BaseHtmlElement $bar)
+    protected function assembleBar(BaseHtmlElement $bar): void
     {
         parent::assembleBar($bar);
         if ($this->usedHost !== null && $this->capacity !== null) {
diff --git a/library/Vspheredb/Web/Widget/OverallStatusRenderer.php b/library/Vspheredb/Web/Widget/OverallStatusRenderer.php
index 49ff4cdb..3e227fa1 100644
--- a/library/Vspheredb/Web/Widget/OverallStatusRenderer.php
+++ b/library/Vspheredb/Web/Widget/OverallStatusRenderer.php
@@ -13,11 +13,7 @@ class OverallStatusRenderer extends Html
     public function __invoke($state)
     {
         if (is_object($state)) {
-            if (isset($state->runtime_power_state)) {
-                $powerState = $state->runtime_power_state;
-            } else {
-                $powerState = null;
-            }
+            $powerState = $state->runtime_power_state ?? null;
             $state = $state->overall_status;
         } else {
             $powerState = null;
@@ -26,13 +22,11 @@ public function __invoke($state)
         if ($powerState === null || $powerState === 'poweredOn') {
             return Icon::create($state === 'green' ? 'ok' : 'warning-empty', [
                 'title' => $this->getStatusDescription($state),
-                'class' => [ 'state', $state ]
+                'class' => ['state', $state]
             ]);
-        } else {
-            $powerInfo = new PowerStateRenderer();
-
-            return $powerInfo($powerState);
         }
+
+        return (new PowerStateRenderer())($powerState);
     }
 
     /**
@@ -42,13 +36,11 @@ public function __invoke($state)
      */
     protected function getStatusDescription(string $status): string
     {
-        $descriptions = [
+        return match ($status) {
             'gray'   => $this->translate('Gray - status is unknown'),
             'green'  => $this->translate('Green - everything is fine'),
             'yellow' => $this->translate('Yellow - there are warnings'),
-            'red'    => $this->translate('Red - there is a problem'),
-        ];
-
-        return $descriptions[$status];
+            'red'    => $this->translate('Red - there is a problem')
+        };
     }
 }
diff --git a/library/Vspheredb/Web/Widget/PowerStateRenderer.php b/library/Vspheredb/Web/Widget/PowerStateRenderer.php
index 0220be8e..71eef67c 100644
--- a/library/Vspheredb/Web/Widget/PowerStateRenderer.php
+++ b/library/Vspheredb/Web/Widget/PowerStateRenderer.php
@@ -15,9 +15,10 @@ public function __invoke($state)
         if (is_object($state)) {
             $state = $state->runtime_power_state;
         }
+
         return Icon::create('off', [
             'title' => $this->getPowerStateDescription($state),
-            'class' => [ 'state', $state ]
+            'class' => ['state', $state]
         ]);
     }
 
@@ -28,18 +29,20 @@ public function __invoke($state)
      */
     public function getPowerStateDescription(string $state): string
     {
-        $descriptions = [
+        $result = match ($state) {
             'poweredOn'  => $this->translate('Powered on'),
             'poweredOff' => $this->translate('Powered off'),
             'suspended'  => $this->translate('Suspended'),
             'standby'    => $this->translate('Standby'),
             'unknown'    => $this->translate('Power state is unknown (disconnected?)'),
-        ];
+            default      => null
+        };
 
-        if (! array_key_exists($state, $descriptions)) {
+        if ($result === null) {
             var_dump($state);
             return 'nono';
         }
-        return $descriptions[$state];
+
+        return $result;
     }
 }
diff --git a/library/Vspheredb/Web/Widget/Renderer/GuestToolsVersionRenderer.php b/library/Vspheredb/Web/Widget/Renderer/GuestToolsVersionRenderer.php
index 2dc5f553..e7dd0617 100644
--- a/library/Vspheredb/Web/Widget/Renderer/GuestToolsVersionRenderer.php
+++ b/library/Vspheredb/Web/Widget/Renderer/GuestToolsVersionRenderer.php
@@ -6,17 +6,17 @@ class GuestToolsVersionRenderer
 {
     public function __invoke($version)
     {
-        if (\is_object($version)) {
+        if (is_object($version)) {
             $version = $version->guest_tools_version;
         }
         if ($version === null || $version === '0') {
             return '-';
         }
         if (
-            \preg_match('/^([89])(\d{1})(\d{2})$/', $version, $m)
-            || \preg_match('/^(1\d)(\d{1})(\d{2})$/', $version, $m)
+            preg_match('/^([89])(\d{1})(\d{2})$/', $version, $m)
+            || preg_match('/^(1\d)(\d{1})(\d{2})$/', $version, $m)
         ) {
-            $version = \sprintf('%d.%d.%d', $m[1], $m[2], $m[3]);
+            $version = sprintf('%d.%d.%d', $m[1], $m[2], $m[3]);
         }
 
         return $version;
diff --git a/library/Vspheredb/Web/Widget/Renderer/PathToObjectRenderer.php b/library/Vspheredb/Web/Widget/Renderer/PathToObjectRenderer.php
index 1ab91d4c..b96a15a2 100644
--- a/library/Vspheredb/Web/Widget/Renderer/PathToObjectRenderer.php
+++ b/library/Vspheredb/Web/Widget/Renderer/PathToObjectRenderer.php
@@ -4,6 +4,7 @@
 
 use gipfl\IcingaWeb2\Link;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
+use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
 use Icinga\Module\Vspheredb\DbObject\Datastore;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
@@ -12,35 +13,32 @@
 use Icinga\Module\Vspheredb\Util;
 use InvalidArgumentException;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 
 class PathToObjectRenderer
 {
-    protected $classLinkMap = [
+    protected array $classLinkMap = [
         VirtualMachine::class => 'vspheredb/vms',
         HostSystem::class     => 'vspheredb/hosts',
-        Datastore::class      => 'vspheredb/datastores',
+        Datastore::class      => 'vspheredb/datastores'
     ];
 
-    public static function render(BaseDbObject $object)
+    public static function render(BaseDbObject $object): HtmlElement
     {
-        $instance = new static();
-
-        return $instance($object);
+        return (new static())($object);
     }
 
-    public function __invoke(BaseDbObject $object)
+    public function __invoke(BaseDbObject $object): HtmlElement
     {
         $uuid = $object->get('uuid');
-        /** @var \Icinga\Module\Vspheredb\Db $connection */
+        /** @var Db $connection */
         $connection = $object->getConnection();
         $lookup =  new PathLookup($connection->getDbAdapter());
-        $class = \get_class($object);
+        $class = get_class($object);
         if (isset($this->classLinkMap[$class])) {
             $baseUrl = $this->classLinkMap[$class];
         } else {
-            throw new InvalidArgumentException(
-                "PathToObjectRenderer doesn't support $class"
-            );
+            throw new InvalidArgumentException("PathToObjectRenderer doesn't support $class");
         }
         $path = Html::tag('span', ['class' => 'dc-path']);
         $parts = [];
@@ -55,8 +53,7 @@ public function __invoke(BaseDbObject $object)
                 ['data-base-target' => '_main']
             );
         }
-        $path->add($parts);
 
-        return $path;
+        return $path->add($parts);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/ResourceUsage.php b/library/Vspheredb/Web/Widget/ResourceUsage.php
index 1ed9cc63..acc1471a 100644
--- a/library/Vspheredb/Web/Widget/ResourceUsage.php
+++ b/library/Vspheredb/Web/Widget/ResourceUsage.php
@@ -3,18 +3,25 @@
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
 use gipfl\Json\JsonSerialization;
+use ReturnTypeWillChange;
 
 class ResourceUsage implements JsonSerialization
 {
-    public $usedMhz;
-    public $totalMhz;
-    public $usedMb;
-    public $totalMb;
-    public $dsCapacity;
-    public $dsFreeSpace;
-    public $dsUncommitted;
-
-    public static function fromSerialization($any)
+    public ?int $usedMhz = null;
+
+    public ?int $totalMhz = null;
+
+    public ?int $usedMb = null;
+
+    public ?int $totalMb = null;
+
+    public ?int $dsCapacity = null;
+
+    public ?int $dsFreeSpace = null;
+
+    public ?int $dsUncommitted = null;
+
+    public static function fromSerialization($any): static
     {
         $self = new static();
         $self->usedMhz       = $any->used_mhz;
@@ -28,8 +35,8 @@ public static function fromSerialization($any)
         return $self;
     }
 
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): array
     {
         return [
             'used_mhz'        => $this->usedMhz,
@@ -38,7 +45,7 @@ public function jsonSerialize()
             'total_mb'        => $this->totalMb,
             'ds_capacity'     => $this->dsCapacity,
             'ds_free_space'   => $this->dsFreeSpace,
-            'ds_uncommitted'  => $this->dsUncommitted,
+            'ds_uncommitted'  => $this->dsUncommitted
         ];
     }
 }
diff --git a/library/Vspheredb/Web/Widget/ResourceUsageLoader.php b/library/Vspheredb/Web/Widget/ResourceUsageLoader.php
index 511dce1c..2a5cff60 100644
--- a/library/Vspheredb/Web/Widget/ResourceUsageLoader.php
+++ b/library/Vspheredb/Web/Widget/ResourceUsageLoader.php
@@ -5,62 +5,59 @@
 use gipfl\ZfDb\Adapter\Adapter;
 use Icinga\Module\Vspheredb\PathLookup;
 use Ramsey\Uuid\UuidInterface;
+use Zend_Db_Adapter_Abstract;
 
 class ResourceUsageLoader
 {
-    /** @var UuidInterface */
-    protected $vCenterUuid;
+    protected ?UuidInterface $vCenterUuid = null;
 
-    /** @var Adapter|\Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected Adapter|Zend_Db_Adapter_Abstract $db;
 
-    /** @var array */
-    protected $parentUuids;
+    protected ?array $parentUuids = null;
 
     /**
-     * @param Adapter|\Zend_Db_Adapter_Abstract $db
+     * @param Adapter|Zend_Db_Adapter_Abstract $db
      */
-    public function __construct($db)
+    public function __construct(Adapter|Zend_Db_Adapter_Abstract $db)
     {
         $this->db = $db;
     }
 
     /**
-     * @param UuidInterface|null $vCenterUuid
+     * @param ?UuidInterface $vCenterUuid
      * @return $this
      */
-    public function filterVCenterUuid(?UuidInterface $vCenterUuid = null)
+    public function filterVCenterUuid(?UuidInterface $vCenterUuid = null): static
     {
         $this->vCenterUuid = $vCenterUuid;
 
         return $this;
     }
 
-    public function filterByParentUuid($uuid)
+    public function filterByParentUuid(string $uuid): static
     {
-        $lookup = new PathLookup($this->db);
-        $this->parentUuids = $lookup->listFoldersBelongingTo($uuid);
+        $this->parentUuids = (new PathLookup($this->db))->listFoldersBelongingTo($uuid);
 
         return $this;
     }
 
-    public function fetch()
+    public function fetch(): ResourceUsage
     {
         $db = $this->db;
-        $query = $db->select()->from(['h' => 'host_system'], [
-            'used_mhz'  => 'SUM(hqs.overall_cpu_usage)',
-            'total_mhz' => 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)',
-            'used_mb'   => 'SUM(hqs.overall_memory_usage_mb)',
-            'total_mb'  => 'SUM(h.hardware_memory_size_mb)',
-        ])->join([
-            'hqs' => 'host_quick_stats'
-        ], 'h.uuid = hqs.uuid', []);
+        $query = $db->select()
+            ->from(['h' => 'host_system'], [
+                'used_mhz'  => 'SUM(hqs.overall_cpu_usage)',
+                'total_mhz' => 'SUM(h.hardware_cpu_cores * h.hardware_cpu_mhz)',
+                'used_mb'   => 'SUM(hqs.overall_memory_usage_mb)',
+                'total_mb'  => 'SUM(h.hardware_memory_size_mb)'
+            ])
+            ->join(['hqs' => 'host_quick_stats'], 'h.uuid = hqs.uuid', []);
         $compute = $db->fetchRow($this->applyFilters($query, 'h'));
 
         $query = $db->select()->from(['ds' => 'datastore'], [
             'ds_capacity'    => 'SUM(ds.capacity)',
             'ds_free_space'  => 'SUM(ds.free_space)',
-            'ds_uncommitted' => 'SUM(ds.uncommitted)',
+            'ds_uncommitted' => 'SUM(ds.uncommitted)'
         ]);
         $storage = $db->fetchRow($this->applyFilters($query, 'ds'));
 
diff --git a/library/Vspheredb/Web/Widget/ServiceTagRenderer.php b/library/Vspheredb/Web/Widget/ServiceTagRenderer.php
index 6b644aaa..fbc4f96c 100644
--- a/library/Vspheredb/Web/Widget/ServiceTagRenderer.php
+++ b/library/Vspheredb/Web/Widget/ServiceTagRenderer.php
@@ -5,50 +5,48 @@
 use gipfl\IcingaWeb2\Icon;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\I18n\Translation;
 
 class ServiceTagRenderer extends Html
 {
     use Translation;
 
-    public function __invoke($host)
+    public function __invoke($host): HtmlElement|string|null
     {
-        if (! $host instanceof  HostSystem) {
+        if (! $host instanceof HostSystem) {
             $host = HostSystem::create([
                 'service_tag'    => $host->service_tag,
-                'sysinfo_vendor' => $host->sysinfo_vendor,
+                'sysinfo_vendor' => $host->sysinfo_vendor
             ]);
         }
 
         return $this->getFormattedServiceTag($host);
     }
 
-    protected function getFormattedServiceTag(HostSystem $host)
+    protected function getFormattedServiceTag(HostSystem $host): HtmlElement|string|null
     {
         if ($host->get('sysinfo_vendor') === 'Dell Inc.') {
             return $this->linkToDellSupport($host->get('service_tag'));
-        } else {
-            return $host->get('service_tag');
         }
+
+        return $host->get('service_tag');
     }
 
-    protected function linkToDellSupport($serviceTag)
+    protected function linkToDellSupport(?string $serviceTag): ?HtmlElement
     {
         if ($serviceTag === null) {
             return null;
         }
-        $urlPattern = 'http://www.dell.com/support/home/product-support/servicetag/%s/drivers';
-
-        $url = sprintf(
-            $urlPattern,
-            strtolower($serviceTag)
-        );
 
         return Html::tag('a', [
-                'href'   => $url,
-                'target' => '_blank',
-                'title'  => $this->translate('Dell Support Page'),
-                'rel'    => 'noreferrer'
+            'href'   => sprintf(
+                'http://www.dell.com/support/home/product-support/servicetag/%s/drivers',
+                strtolower($serviceTag)
+            ),
+            'target' => '_blank',
+            'title'  => $this->translate('Dell Support Page'),
+            'rel'    => 'noreferrer'
         ], [Icon::create('forward'), $serviceTag]);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/SimpleUsageBar.php b/library/Vspheredb/Web/Widget/SimpleUsageBar.php
index eb6e46ce..ab6b3e40 100644
--- a/library/Vspheredb/Web/Widget/SimpleUsageBar.php
+++ b/library/Vspheredb/Web/Widget/SimpleUsageBar.php
@@ -15,23 +15,20 @@ class SimpleUsageBar extends BaseHtmlElement
         'data-base-target' => '_next'
     ];
 
-    /** @var int */
-    protected $used;
+    protected int $used;
 
-    /** @var int */
-    protected $total;
+    protected int $total;
 
-    /** @var string */
-    protected $title;
+    protected string $title;
 
-    public function __construct($used, $total, $title)
+    public function __construct(int $used, int $total, string $title)
     {
         $this->used = $used;
         $this->total = $total;
         $this->title = $title;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $usedPercent = $this->used / $this->total;
 
diff --git a/library/Vspheredb/Web/Widget/SubTitle.php b/library/Vspheredb/Web/Widget/SubTitle.php
index 397cec39..9e78f650 100644
--- a/library/Vspheredb/Web/Widget/SubTitle.php
+++ b/library/Vspheredb/Web/Widget/SubTitle.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
+use ipl\Html\Attributes;
 use ipl\Html\BaseHtmlElement;
 
 class SubTitle extends BaseHtmlElement
@@ -10,14 +11,15 @@ class SubTitle extends BaseHtmlElement
 
     /**
      * SubTitle constructor.
+     *
      * @param string $title
-     * @param string|null $icon
+     * @param ?string $icon
      */
-    public function __construct($title, $icon = null)
+    public function __construct(string $title, ?string $icon = null)
     {
         $this->setContent($title);
         if ($icon !== null) {
-            $this->addAttributes(['class' => "icon-$icon"]);
+            $this->addAttributes(Attributes::create(['class' => "icon-$icon"]));
         }
     }
 }
diff --git a/library/Vspheredb/Web/Widget/Summaries.php b/library/Vspheredb/Web/Widget/Summaries.php
index 31e8a2a5..0a6e0920 100644
--- a/library/Vspheredb/Web/Widget/Summaries.php
+++ b/library/Vspheredb/Web/Widget/Summaries.php
@@ -4,13 +4,14 @@
 
 use gipfl\IcingaWeb2\Icon;
 use gipfl\IcingaWeb2\Link;
-use ipl\I18n\Translation;
 use gipfl\IcingaWeb2\Url;
 use Icinga\Module\Vspheredb\Db;
 use Icinga\Module\Vspheredb\Web\Table\Objects\ObjectsTable;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
+use ipl\I18n\Translation;
 use RuntimeException;
+use Zend_Db_Adapter_Abstract;
 use Zend_Db_Select as ZfSelect;
 use Zend_Db_Select_Exception;
 
@@ -20,22 +21,17 @@ class Summaries extends BaseHtmlElement
 
     protected $tag = 'div';
 
-    protected $defaultAttributes = [
-        'class' => 'object-summaries',
-    ];
+    protected $defaultAttributes = ['class' => 'object-summaries'];
 
-    /** @var \Zend_Db_Select */
-    protected $query;
+    protected ?ZfSelect $query = null;
 
-    protected $stats;
+    protected ?object $stats = null;
 
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
 
-    /** @var Url */
-    protected $baseUrl;
+    protected Url $baseUrl;
 
-    protected $wantsPowerState = false;
+    protected bool $wantsPowerState = false;
 
     /**
      * Summaries constructor.
@@ -56,9 +52,10 @@ public function __construct(ObjectsTable $table, Db $db, Url $baseUrl)
 
     /**
      * @param ObjectsTable $table
-     * @throws \Zend_Db_Select_Exception
+     *
+     * @throws Zend_Db_Select_Exception
      */
-    protected function setTable(ObjectsTable $table)
+    protected function setTable(ObjectsTable $table): void
     {
         $this->setQueryFromTable($table);
         $this->addColumn('o.overall_status', ['gray', 'green', 'yellow', 'red']);
@@ -72,7 +69,7 @@ protected function setTable(ObjectsTable $table)
                 'poweredOff',
                 'unknown',
                 'standby',
-                'suspended',
+                'suspended'
             ]);
 
             $this->wantsPowerState = true;
@@ -81,7 +78,7 @@ protected function setTable(ObjectsTable $table)
         $this->applyUrlFilters($table);
     }
 
-    protected function applyUrlFilters(ObjectsTable $table)
+    protected function applyUrlFilters(ObjectsTable $table): void
     {
         foreach ($this->baseUrl->getParams()->toArray() as $param) {
             if ($table->hasColumn($param[0])) {
@@ -102,9 +99,10 @@ protected function applyUrlFilters(ObjectsTable $table)
 
     /**
      * @param ObjectsTable $table
-     * @throws \Zend_Db_Select_Exception
+     *
+     * @throws Zend_Db_Select_Exception
      */
-    protected function setQueryFromTable(ObjectsTable $table)
+    protected function setQueryFromTable(ObjectsTable $table): void
     {
         $query = clone($table->getQuery());
         $query->reset(ZfSelect::LIMIT_COUNT);
@@ -114,9 +112,7 @@ protected function setQueryFromTable(ObjectsTable $table)
 
         // This works, but is not as general-purpose as it should be
         if (count($query->getPart(ZfSelect::GROUP)) > 0) {
-            $query = $query->getAdapter()->select()->from([
-                'o' => $query->columns('o.overall_status')
-            ], []);
+            $query = $query->getAdapter()->select()->from(['o' => $query->columns('o.overall_status')], []);
         }
 
         $this->query = $query;
@@ -125,9 +121,10 @@ protected function setQueryFromTable(ObjectsTable $table)
     /**
      * @param $column
      * @param $variants
-     * @throws \Zend_Db_Select_Exception
+     *
+     * @throws Zend_Db_Select_Exception
      */
-    protected function addColumn($column, $variants)
+    protected function addColumn($column, $variants): void
     {
         $columns = [];
         foreach ($variants as $value) {
@@ -136,26 +133,22 @@ protected function addColumn($column, $variants)
         $this->query->columns($columns);
     }
 
-    protected function makeColumnAlias($column)
+    protected function makeColumnAlias($column): string
     {
         return 'cnt_' . strtolower(preg_replace('/^.+?\./', '', $column));
     }
 
-    protected function countFiltered($column, $value)
+    protected function countFiltered($column, $value): string
     {
         return "SUM(CASE WHEN $column = '$value' THEN 1 ELSE 0 END)";
     }
 
     protected function stats()
     {
-        if ($this->stats === null) {
-            $this->stats = $this->db->fetchRow($this->query);
-        }
-
-        return $this->stats;
+        return $this->stats ??= $this->db->fetchRow($this->query);
     }
 
-    public function addPowerState()
+    public function addPowerState(): static
     {
         return $this;
     }
@@ -168,8 +161,7 @@ public function addPowerState()
      */
     protected function createSummaryLink(string $value, string $property): ?Link
     {
-        $stats = $this->stats();
-        $count = (int) $stats->{"cnt_$value"};
+        $count = (int) $this->stats()->{"cnt_$value"};
 
         if ($count === 0) {
             return null;
@@ -205,16 +197,11 @@ protected function addSummaryLinks(string $column, array $variants): void
         $this->add($span);
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->setSeparator(' ');
         $this->add([Icon::create('ok'), $this->translate('Status') . ': ']);
-        $this->addSummaryLinks('overall_status', [
-            'red',
-            'yellow',
-            'gray',
-            'green'
-        ]);
+        $this->addSummaryLinks('overall_status', ['red', 'yellow', 'gray', 'green']);
         if ($this->wantsPowerState) {
             $this->add([Icon::create('off'), $this->translate('Power') . ': ']);
             $this->addSummaryLinks('runtime_power_state', [
diff --git a/library/Vspheredb/Web/Widget/TaggingDetails.php b/library/Vspheredb/Web/Widget/TaggingDetails.php
index ae04e6e5..336a615b 100644
--- a/library/Vspheredb/Web/Widget/TaggingDetails.php
+++ b/library/Vspheredb/Web/Widget/TaggingDetails.php
@@ -4,13 +4,11 @@
 
 use gipfl\Json\JsonString;
 use gipfl\Web\Table\NameValueTable;
-use Icinga\Module\Vspheredb\DbObject\BaseDbObject;
 use Icinga\Module\Vspheredb\DbObject\HostSystem;
 use Icinga\Module\Vspheredb\DbObject\TaggingCategory;
 use Icinga\Module\Vspheredb\DbObject\TaggingObjectTag;
 use Icinga\Module\Vspheredb\DbObject\TaggingTag;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
-use InvalidArgumentException;
 use ipl\Html\Html;
 use ipl\Html\HtmlDocument;
 use ipl\I18n\Translation;
@@ -20,29 +18,21 @@ class TaggingDetails extends HtmlDocument
 {
     use Translation;
 
-    /** @var HostSystem|VirtualMachine */
-    protected $object;
+    protected HostSystem|VirtualMachine $object;
 
-    /**
-     * @var TaggingTag[]
-     */
-    protected $tags;
-    /**
-     * @var TaggingCategory[]
-     */
-    protected $categories;
+    /** @var TaggingTag[] */
+    protected array $tags;
 
-    public function __construct(BaseDbObject $object)
+    /** @var TaggingCategory[] */
+    protected array $categories;
+
+    public function __construct(HostSystem|VirtualMachine $object)
     {
-        if (! $object instanceof HostSystem && ! $object instanceof VirtualMachine) {
-            throw new InvalidArgumentException(
-                'HostSystem or VirtualMachine expected, got ' . \get_class($object)
-            );
-        }
         $this->object = $object;
         $connection = $object->getConnection();
         $db = $connection->getDbAdapter();
-        $where = $db->select()->from(['tt' => TaggingTag::TABLE], 'tt.*')
+        $where = $db->select()
+            ->from(['tt' => TaggingTag::TABLE], 'tt.*')
             ->join(['tot' => TaggingObjectTag::TABLE], 'tot.tag_uuid = tt.uuid', [])
             ->where('tot.object_uuid = ?', $object->get('uuid'))
             ->order('tt.name');
@@ -58,7 +48,7 @@ public function __construct(BaseDbObject $object)
         // $this->setDemoTags();
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $this->prepend(new SubTitle($this->translate('Tags'), 'tags'));
         $internal = JsonString::decode($this->object->object()->get('tags'));
@@ -67,17 +57,14 @@ protected function assemble()
 
         if (empty($this->tags) && empty($internal)) {
             $this->add($this->translate('No tags been defined'));
+
             return;
         }
         $table = NameValueTable::create();
         $this->add($table);
 
         foreach ($this->categories as $category) {
-            if ($category->cardinalityIsSingle()) {
-                $parent = new HtmlDocument();
-            } else {
-                $parent = Html::tag('ul');
-            }
+            $parent = $category->cardinalityIsSingle() ? new HtmlDocument() : Html::tag('ul');
             foreach ($this->tags as $tag) {
                 if ($tag->get('category_uuid') === $category->get('uuid')) {
                     $tagName = $tag->get('name');
@@ -85,11 +72,7 @@ protected function assemble()
                     if ($description !== null && $description !== '') {
                         $tagName = Html::tag('span', ['class' => 'hover-hint', 'title' => $description], $tagName);
                     }
-                    if ($category->cardinalityIsSingle()) {
-                        $parent->add($tagName);
-                    } else {
-                        $parent->add(Html::tag('li', $tagName));
-                    }
+                    $parent->add($category->cardinalityIsSingle() ? $tagName : Html::tag('li', $tagName));
                 }
             }
             $table->addNameValueRow($category->get('name'), $parent);
@@ -105,13 +88,14 @@ protected function assemble()
                 }
                 // Other example, for DistributedVirtualPortgroup: has "SYSTEM/DVS.UPLINKPG" for dvUplink Portgroup
             }
-            $table->addNameValueRow([
-                Html::tag('i', $this->translate('Internal')),
-            ], Html::tag('ul', Html::wrapEach($internal, 'li')));
+            $table->addNameValueRow(
+                [Html::tag('i', $this->translate('Internal'))],
+                Html::tag('ul', Html::wrapEach($internal, 'li'))
+            );
         }
     }
 
-    protected function setDemoTags()
+    protected function setDemoTags(): void
     {
         $uuidCat1 = Uuid::fromString('a09657cb-0c0f-4c32-93de-f98a1a3e5229')->getBytes();
         $uuidCat2 = Uuid::fromString('b2272134-f552-44b4-b1c9-56fdb8d9b80b')->getBytes();
@@ -119,28 +103,28 @@ protected function setDemoTags()
             TaggingTag::create([
                 'category_uuid' => $uuidCat1,
                 'name' => 'Prod',
-                'description' => 'Our production environment',
+                'description' => 'Our production environment'
             ]),
             TaggingTag::create([
                 'category_uuid' => $uuidCat2,
-                'name' => 'Another Corp.',
+                'name' => 'Another Corp.'
             ]),
             TaggingTag::create([
                 'category_uuid' => $uuidCat2,
-                'name' => 'Contoso Inc',
-            ]),
+                'name' => 'Contoso Inc'
+            ])
         ];
         $this->categories = [
             $uuidCat1 => TaggingCategory::create([
                 'uuid' => $uuidCat1,
                 'name' => 'Environment',
-                'cardinality' => 'SINGLE',
+                'cardinality' => 'SINGLE'
             ]),
             $uuidCat2 => TaggingCategory::create([
                 'uuid' => $uuidCat2,
                 'name' => 'Customer',
-                'cardinality' => 'MULTIPLE',
-            ]),
+                'cardinality' => 'MULTIPLE'
+            ])
         ];
     }
 }
diff --git a/library/Vspheredb/Web/Widget/ToggleFlagList.php b/library/Vspheredb/Web/Widget/ToggleFlagList.php
index b183edb4..c2a50e03 100644
--- a/library/Vspheredb/Web/Widget/ToggleFlagList.php
+++ b/library/Vspheredb/Web/Widget/ToggleFlagList.php
@@ -6,6 +6,7 @@
 use gipfl\IcingaWeb2\Url;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\I18n\Translation;
 use Zend_Db_Select as DbSelect;
 
@@ -15,29 +16,25 @@ abstract class ToggleFlagList extends BaseHtmlElement
 
     protected $tag = 'li';
 
-    /** @var Url */
-    private $url;
+    private Url $url;
 
-    /** @var string */
-    private $param;
+    private string $param;
 
-    /** @var DbSelect|null */
-    private $originalQuery;
+    private ?DbSelect $originalQuery = null;
 
-    /** @var DbSelect|null */
-    private $query;
+    private ?DbSelect $query = null;
 
-    protected $iconMain = 'angle-double-down';
+    protected string $iconMain = 'angle-double-down';
 
-    protected $iconModified = 'flapping';
+    protected string $iconModified = 'flapping';
 
-    public function __construct(Url $url, $param)
+    public function __construct(Url $url, string $param)
     {
         $this->url = $url;
         $this->param = $param;
     }
 
-    public function applyToQuery(DbSelect $query)
+    public function applyToQuery(DbSelect $query): static
     {
         $this->originalQuery = $query;
         $this->query = clone $query;
@@ -45,16 +42,16 @@ public function applyToQuery(DbSelect $query)
         return $this;
     }
 
-    abstract protected function getListLabel();
+    abstract protected function getListLabel(): string;
 
-    abstract protected function getOptions();
+    abstract protected function getOptions(): array;
 
-    protected function getDefaultSelection()
+    protected function getDefaultSelection(): array
     {
-        return \array_keys($this->getOptions());
+        return array_keys($this->getOptions());
     }
 
-    protected function setEnabled($enabled, $all)
+    protected function setEnabled(array $enabled, array $all): void
     {
         if ($all === $enabled) {
             // No need to extend the query with useless overhead
@@ -65,24 +62,18 @@ protected function setEnabled($enabled, $all)
             if (empty($enabled)) {
                 $this->originalQuery->where('1 = 0');
             } else {
-                $this->originalQuery->where(
-                    $this->param . ' IN (?)',
-                    $enabled
-                );
+                $this->originalQuery->where($this->param . ' IN (?)', $enabled);
             }
         }
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $link = Link::create($this->getListLabel(), '#', null, ['class' => 'icon-' . $this->iconMain]);
-        $this->add([
-            $link,
-            $this->createLinkList($this->toggleColumnsOptions($link))
-        ]);
+        $this->add([$link, $this->createLinkList($this->toggleColumnsOptions($link))]);
     }
 
-    protected function toggleColumnsOptions(Link $mainLink)
+    protected function toggleColumnsOptions(Link $mainLink): array
     {
         $default = $this->getDefaultSelection();
         $links = [];
@@ -93,10 +84,7 @@ protected function toggleColumnsOptions(Link $mainLink)
         if ($enabled === null) {
             $enabled = $default;
         } else {
-            $mainLink->getAttributes()->set(
-                'class',
-                'modified icon-' . $this->iconModified
-            );
+            $mainLink->getAttributes()->set('class', 'modified icon-' . $this->iconModified);
             $links[] = $this->geturlReset();
             $enabled = $this->splitUrlOptions($enabled);
         }
@@ -105,23 +93,23 @@ protected function toggleColumnsOptions(Link $mainLink)
         $disabled = [];
         foreach ($this->getOptions() as $option => $label) {
             $all[] = $option;
-            if (\in_array($option, $enabled)) {
-                $urlOptions = \array_diff($enabled, [$option]);
+            if (in_array($option, $enabled)) {
+                $urlOptions = array_diff($enabled, [$option]);
                 $icon = 'check';
                 $title = $this->translate('Click to hide');
             } else {
                 $disabled[] = $option;
-                $urlOptions = \array_merge($enabled, [$option]);
+                $urlOptions = array_merge($enabled, [$option]);
                 $icon = 'plus';
                 $title = $this->translate('Click to show');
             }
             $links[] = Link::create($label, $this->getUrlWithOptions($urlOptions), null, [
                 'class' => "icon-$icon",
-                'title' => $title,
+                'title' => $title
             ]);
         }
         if (! empty($disabled) && $all !== $default) {
-            \array_unshift($links, Link::create(
+            array_unshift($links, Link::create(
                 $this->translate('All'),
                 $url->with($param, $this->joinUrlOptions($all)),
                 null,
@@ -138,7 +126,7 @@ protected function toggleColumnsOptions(Link $mainLink)
         return $links;
     }
 
-    protected function geturlReset()
+    protected function geturlReset(): Link
     {
         return Link::create(
             $this->translate('Reset'),
@@ -148,22 +136,22 @@ protected function geturlReset()
         );
     }
 
-    protected function getUrlWithOptions($options)
+    protected function getUrlWithOptions($options): Url
     {
         return $this->url->with($this->param, $this->joinUrlOptions($options));
     }
 
-    protected function joinUrlOptions($value)
+    protected function joinUrlOptions($value): string
     {
-        return \implode(',', $value);
+        return implode(',', $value);
     }
 
-    protected function splitUrlOptions($value)
+    protected function splitUrlOptions($value): array
     {
-        return \preg_split('/,/', $value, -1, PREG_SPLIT_NO_EMPTY);
+        return preg_split('/,/', $value, -1, PREG_SPLIT_NO_EMPTY);
     }
 
-    protected function createLinkList($links)
+    protected function createLinkList($links): HtmlElement
     {
         $ul = Html::tag('ul');
 
diff --git a/library/Vspheredb/Web/Widget/ToggleTableColumns.php b/library/Vspheredb/Web/Widget/ToggleTableColumns.php
index 6a50ab68..0b350b0b 100644
--- a/library/Vspheredb/Web/Widget/ToggleTableColumns.php
+++ b/library/Vspheredb/Web/Widget/ToggleTableColumns.php
@@ -7,12 +7,11 @@
 
 class ToggleTableColumns extends ToggleFlagList
 {
-    /** @var BaseTable */
-    protected $table;
+    protected BaseTable $table;
 
-    protected $iconMain = 'th-list';
+    protected string $iconMain = 'th-list';
 
-    protected $iconModified = 'th-list';
+    protected string $iconModified = 'th-list';
 
     public function __construct(BaseTable $table, Url $url)
     {
@@ -20,23 +19,23 @@ public function __construct(BaseTable $table, Url $url)
         $this->table = $table;
     }
 
-    protected function getListLabel()
+    protected function getListLabel(): string
     {
         return '';
         // return $this->translate('Columns');
     }
 
-    protected function getDefaultSelection()
+    protected function getDefaultSelection(): array
     {
         return $this->table->getChosenColumnNames();
     }
 
-    protected function setEnabled($enabled, $all)
+    protected function setEnabled(array $enabled, array $all): void
     {
         $this->table->chooseColumns($enabled);
     }
 
-    protected function getOptions()
+    protected function getOptions(): array
     {
         $options = [];
         foreach ($this->table->getAvailableColumns() as $column) {
diff --git a/library/Vspheredb/Web/Widget/UsageBar.php b/library/Vspheredb/Web/Widget/UsageBar.php
index 86bc2b61..eb08e439 100644
--- a/library/Vspheredb/Web/Widget/UsageBar.php
+++ b/library/Vspheredb/Web/Widget/UsageBar.php
@@ -2,6 +2,7 @@
 
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
+use Closure;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
 use ipl\I18n\Translation;
@@ -13,67 +14,53 @@ class UsageBar extends BaseHtmlElement
 
     protected $tag = 'div';
 
-    protected $defaultAttributes = [
-        'class' => 'resource-usage',
-    ];
+    protected $defaultAttributes = ['class' => 'resource-usage'];
 
-    protected $colors = [
-        'used' => 'rgba(0, 149, 191, 0.75)',
-    ];
+    protected array $colors = ['used' => 'rgba(0, 149, 191, 0.75)'];
 
-    /** @var int */
-    protected $used;
+    protected int|float|null $used;
 
-    /** @var int */
-    protected $capacity;
+    protected int|float|null $capacity;
 
-    protected $formatter;
+    protected ?Closure $formatter = null;
 
-    protected $showLabels = true;
+    protected bool $showLabels = true;
 
-    public function __construct($used, $capacity)
+    public function __construct(int|float|null $used, int|float|null $capacity)
     {
         $this->used = $used;
         $this->capacity = $capacity;
     }
 
     /**
-     * @param $percent
-     * @param $title
+     * @param float|int $percent
+     * @param string $title
      * @param string $color
      *
      * @return array
      */
-    protected function makeSegment($percent, $title, string $color = 'used'): array
+    protected function makeSegment(float|int $percent, string $title, string $color = 'used'): array
     {
-        if (isset($this->colors[$color])) {
-            $color = $this->colors[$color];
-        }
-
-        $usage = Html::tag('div', [
-            'class' => 'usage',
-            'title' => $title
-        ]);
-
+        $usage = Html::tag('div', ['class' => 'usage', 'title' => $title]);
 
         $style = (new StyleWithNonce())
             ->setModule('vspheredb')
             ->addFor($usage, [
-                'width' => sprintf('%0.3F%%', $percent * 100),
-                'background-color' => $color,
+                'width'            => sprintf('%0.3F%%', $percent * 100),
+                'background-color' => $this->colors[$color] ?? $color
             ]);
 
         return [$usage, $style];
     }
 
-    public function setFormatter($callback)
+    public function setFormatter($callback): static
     {
         $this->formatter = $callback;
 
         return $this;
     }
 
-    public function showLabels($show = true)
+    public function showLabels($show = true): static
     {
         $this->showLabels = (bool) $show;
         return $this;
@@ -83,14 +70,12 @@ protected function format($value)
     {
         if ($this->formatter === null) {
             return $value;
-        } else {
-            $formatter = $this->formatter;
-
-            return $formatter($value);
         }
+
+        return ($this->formatter)($value);
     }
 
-    protected function getTitleUsed()
+    protected function getTitleUsed(): string
     {
         return sprintf(
             $this->translate('Used: %s of %s (%.2F%%)'),
@@ -100,29 +85,26 @@ protected function getTitleUsed()
         );
     }
 
-    protected function getLabelUsed()
+    protected function getLabelUsed(): string
     {
         return sprintf($this->translate('%s used'), $this->format($this->used));
     }
 
-    protected function getLabelCapacity()
+    protected function getLabelCapacity(): string
     {
         return $this->translate('Capacity') . ': ' . $this->format($this->capacity);
     }
 
-    protected function assembleBar(BaseHtmlElement $bar)
+    protected function assembleBar(BaseHtmlElement $bar): void
     {
         if ($this->capacity !== null && $this->capacity !== 0) {
             $bar->add($this->makeSegment($this->used / $this->capacity, $this->getTitleUsed()));
         }
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
-        $usage = Html::tag('div', [
-            'class' => 'usage-bar',
-            'data-base-target' => '_next',
-        ]);
+        $usage = Html::tag('div', ['class' => 'usage-bar', 'data-base-target' => '_next']);
         $this->assembleBar($usage);
         $this->add($usage);
         if ($this->showLabels) {
@@ -130,16 +112,12 @@ protected function assemble()
         }
     }
 
-    protected function addLabels()
+    protected function addLabels(): void
     {
         $this->add([
-            Html::tag('span', [
-                'class' => 'usage-used'
-            ], $this->getLabelUsed()),
+            Html::tag('span', ['class' => 'usage-used'], $this->getLabelUsed()),
             ' ',
-            Html::tag('span', [
-                'class' => 'usage-capacity'
-            ], $this->getLabelCapacity()),
+            Html::tag('span', ['class' => 'usage-capacity'], $this->getLabelCapacity())
         ]);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/UsageSummary.php b/library/Vspheredb/Web/Widget/UsageSummary.php
index c8df3cea..1d64c67a 100644
--- a/library/Vspheredb/Web/Widget/UsageSummary.php
+++ b/library/Vspheredb/Web/Widget/UsageSummary.php
@@ -13,9 +13,7 @@ class UsageSummary extends BaseHtmlElement
 
     protected $tag = 'div';
 
-    protected $defaultAttributes = [
-        'class' => 'usage-summary-widget'
-    ];
+    protected $defaultAttributes = ['class' => 'usage-summary-widget'];
 
     public function __construct(ResourceUsage $usate)
     {
@@ -27,13 +25,13 @@ public function __construct(ResourceUsage $usate)
                 Html::tag('div', $attr, $this->smallUnit(Format::mhz($usate->usedMhz))),
                 Html::tag('span', $this->translate('Total') . ': ' . Format::mhz($usate->totalMhz)),
                 (new CpuUsage($usate->usedMhz, $usate->totalMhz))->showLabels(false),
-                $this->translate('CPU'),
+                $this->translate('CPU')
             ]),
             Html::tag('div', $attrBox, [
                 Html::tag('div', $attr, $this->smallUnit(Format::mBytes($usate->usedMb))),
                 Html::tag('span', $this->translate('Total') . ': ' . Format::mBytes($usate->totalMb)),
                 (new MemoryUsage($usate->usedMb, $usate->totalMb))->showLabels(false),
-                $this->translate('Memory'),
+                $this->translate('Memory')
             ]),
             Html::tag('div', $attrBox, [
                 Html::tag('div', $attr, $this->smallUnit(
@@ -43,24 +41,20 @@ public function __construct(ResourceUsage $usate)
                     'span',
                     $this->translate('Total') . ': ' . Format::mBytes($usate->dsCapacity / $mb)
                 ),
-                (new MemoryUsage(
-                    ($usate->dsCapacity - $usate->dsFreeSpace) / $mb,
-                    $usate->dsCapacity / $mb
-                ))->showLabels(false),
+                (new MemoryUsage(($usate->dsCapacity - $usate->dsFreeSpace) / $mb, $usate->dsCapacity / $mb))
+                    ->showLabels(false),
                 $this->translate('Storage')
-            ]),
+            ])
         ]);
     }
 
-    protected function smallUnit($string)
+    protected function smallUnit(string $string): array
     {
         $parts = explode(' ', $string, 2);
-        if (count($parts) < 2) {
-            return [$parts[0], null];
-        }
+
         return [
             $parts[0],
-            Html::tag('span', ['class' => 'unit'], $parts[1])
+            count($parts) < 2 ? null : Html::tag('span', ['class' => 'unit'], $parts[1])
         ];
     }
 }
diff --git a/library/Vspheredb/Web/Widget/VCenterConnectionStatusIcon.php b/library/Vspheredb/Web/Widget/VCenterConnectionStatusIcon.php
index d0a14ed3..55f8dca0 100644
--- a/library/Vspheredb/Web/Widget/VCenterConnectionStatusIcon.php
+++ b/library/Vspheredb/Web/Widget/VCenterConnectionStatusIcon.php
@@ -11,26 +11,18 @@ class VCenterConnectionStatusIcon
 {
     public static function create(ServerConnectionInfo $info): Icon
     {
-        $state = $info->getState();
-        $title = ConnectionState::describe($info);
-        switch ($state) {
-            case 'unknown':
-                return Icon::create('help', ['class' => 'unknown', 'title' => $title]);
-            case 'disabled':
-                return Icon::create('cancel', ['title' => $title]);
-            case ApiConnection::STATE_CONNECTED:
-                return Icon::create('ok', ['class' => 'green', 'title' => $title]);
-            case ApiConnection::STATE_LOGIN:
-            case ApiConnection::STATE_INIT:
-                return Icon::create('spinner', ['class' => 'yellow', 'title' => $title]);
-            case ApiConnection::STATE_FAILING:
-                return Icon::create('warning-empty', ['class' => 'red', 'title' => $title]);
-            case ApiConnection::STATE_STOPPING:
-                return Icon::create('cancel', ['class' => 'yellow', 'title' => $title]);
-        }
+        $title = ['title' => ConnectionState::describe($info)];
 
-        // Fail, error?
-        return Icon::create('warning-empty', ['class' => 'warning', 'title' => $title]);
+        return match ($info->getState()) {
+            'unknown'                      => Icon::create('help', ['class' => 'unknown'] + $title),
+            'disabled'                     => Icon::create('cancel', $title),
+            ApiConnection::STATE_CONNECTED => Icon::create('ok', ['class' => 'green'] + $title),
+            ApiConnection::STATE_LOGIN,
+            ApiConnection::STATE_INIT      => Icon::create('spinner', ['class' => 'yellow'] + $title),
+            ApiConnection::STATE_FAILING   => Icon::create('warning-empty', ['class' => 'red'] + $title),
+            ApiConnection::STATE_STOPPING  => Icon::create('cancel', ['class' => 'yellow'] + $title),
+            default                        => Icon::create('warning-empty', ['class' => 'warning'] + $title)
+        };
     }
 
     public static function noServer(): Icon
diff --git a/library/Vspheredb/Web/Widget/VCenterHeader.php b/library/Vspheredb/Web/Widget/VCenterHeader.php
index ff349e3f..d6701737 100644
--- a/library/Vspheredb/Web/Widget/VCenterHeader.php
+++ b/library/Vspheredb/Web/Widget/VCenterHeader.php
@@ -8,24 +8,20 @@
 
 class VCenterHeader extends HtmlDocument
 {
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     public function __construct(VCenter $vCenter)
     {
         $this->vCenter = $vCenter;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
-        $vCenter = $this->vCenter;
-        $title = Html::tag('h1', [
-            $vCenter->get('name'),
-            ' ',
-            Html::tag('small', '(' . $vCenter->getFullName() . ')'),
-        ]);
         $this->add([
-            $title,
+            Html::tag(
+                'h1',
+                [$this->vCenter->get('name'), ' ', Html::tag('small', '(' . $this->vCenter->getFullName() . ')')]
+            )
         ]);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/VCenterSummaries.php b/library/Vspheredb/Web/Widget/VCenterSummaries.php
index 9d7b9415..b78fa1fc 100644
--- a/library/Vspheredb/Web/Widget/VCenterSummaries.php
+++ b/library/Vspheredb/Web/Widget/VCenterSummaries.php
@@ -8,6 +8,7 @@
 use Icinga\Module\Vspheredb\Util;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
+use Zend_Db_Select;
 
 class VCenterSummaries extends BaseHtmlElement
 {
@@ -18,43 +19,34 @@ class VCenterSummaries extends BaseHtmlElement
         'data-base-target' => '_next'
     ];
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     public function __construct(VCenter $vCenter)
     {
         $this->vCenter = $vCenter;
     }
 
-    protected function selectObject($type, $columns)
+    protected function selectObject(array|string $type, array $columns): Zend_Db_Select
     {
         $connection = $this->vCenter->getConnection();
-        $db = $connection->getDbAdapter();
-        $vCenterUuid = $this->vCenter->getUuid();
-
-        $query = $db->select()->from(['o' => 'object'], $columns);
-        if (is_array($type)) {
-            $query->where('object_type IN (?)', $type);
-        } else {
-            $query->where('object_type = ?', $type);
-        }
-        $query->where('vcenter_uuid = ?', $connection->quoteBinary($vCenterUuid));
 
-        return $query;
+        return $connection->getDbAdapter()->select()
+            ->from(['o' => 'object'], $columns)
+            ->where('object_type ' . (is_array($type) ? 'IN (?)' : '= ?'), $type)
+            ->where('vcenter_uuid = ?', $connection->quoteBinary($this->vCenter->getUuid()));
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $connection = $this->vCenter->getConnection();
         $db = $connection->getDbAdapter();
-        $vCenterUuid = $this->vCenter->getUuid();
 
         $columns = [
             'total'  => 'COUNT(*)',
             'red'    => "SUM(CASE WHEN o.overall_status = 'red' THEN 1 ELSE 0 END)",
             'yellow' => "SUM(CASE WHEN o.overall_status = 'yellow' THEN 1 ELSE 0 END)",
             'green'  => "SUM(CASE WHEN o.overall_status = 'green' THEN 1 ELSE 0 END)",
-            'gray'   => "SUM(CASE WHEN o.overall_status = 'gray' THEN 1 ELSE 0 END)",
+            'gray'   => "SUM(CASE WHEN o.overall_status = 'gray' THEN 1 ELSE 0 END)"
         ];
 
         $this->addCountlet(
@@ -80,10 +72,11 @@ protected function assemble()
         );
         $this->addCountlet(
             $db->fetchRow(
-                $db->select()->from(['o' => 'object'], $columns)
+                $db->select()
+                    ->from(['o' => 'object'], $columns)
                     ->join(['vm' => 'virtual_machine'], 'vm.uuid = o.uuid', [])
                     ->where('vm.template = ?', 'n')
-                    ->where('vm.vcenter_uuid = ?', $connection->quoteBinary($vCenterUuid))
+                    ->where('vm.vcenter_uuid = ?', $connection->quoteBinary($this->vCenter->getUuid()))
             ),
             'Virtual Machines',
             'vspheredb/vms'
@@ -143,7 +136,7 @@ protected function assemble()
         );
     }
 
-    protected function getWorstState($counters)
+    protected function getWorstState(object $counters): string
     {
         foreach (['red', 'yellow', 'gray', 'green'] as $color) {
             if ($counters->$color > 0) {
@@ -155,17 +148,14 @@ protected function getWorstState($counters)
         return 'gray';
     }
 
-    protected function addCountlet($counters, $title, $url)
+    protected function addCountlet(object $counters, string $title, string $url): void
     {
         if ((int) $counters->total === 0) {
             return;
         }
         $url = Url::fromPath($url)->with('vcenter', Util::niceUuid($this->vCenter->getUuid()));
         $state = $this->getWorstState($counters);
-        $title = Html::tag('h3', [
-            Link::create($title, $url),
-            ' (' . $counters->total . ')'
-        ]);
+        $title = Html::tag('h3', [Link::create($title, $url), ' (' . $counters->total . ')']);
         $cell = Html::tag('div', ['class' => ['summary-countlet', "state-$state"]]);
         $cell->add($title);
 
diff --git a/library/Vspheredb/Web/Widget/VCenterSyncInfo.php b/library/Vspheredb/Web/Widget/VCenterSyncInfo.php
index 253df408..8b7d0e15 100644
--- a/library/Vspheredb/Web/Widget/VCenterSyncInfo.php
+++ b/library/Vspheredb/Web/Widget/VCenterSyncInfo.php
@@ -7,6 +7,7 @@
 use Icinga\Module\Vspheredb\WebUtil;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\I18n\Translation;
 
 class VCenterSyncInfo extends BaseHtmlElement
@@ -17,8 +18,7 @@ class VCenterSyncInfo extends BaseHtmlElement
 
     protected $defaultAttributes = ['class' => 'health'];
 
-    /** @var VCenter */
-    protected $vCenter;
+    protected VCenter $vCenter;
 
     public function __construct(VCenter $vCenter)
     {
@@ -59,19 +59,17 @@ protected function assemble()
         }
     }
 
-    protected function getVersionInfoString()
+    protected function getVersionInfoString(): string
     {
-        $c = $this->vCenter;
-
         return sprintf(
             '%s %s build-%s',
-            $c->get('api_type'),
-            $c->get('version'),
-            $c->get('build')
+            $this->vCenter->get('api_type'),
+            $this->vCenter->get('version'),
+            $this->vCenter->get('build')
         );
     }
 
-    protected function healthDiv($state, $content = null)
+    protected function healthDiv(string $state, $content = null): HtmlElement
     {
         return Html::tag('div', ['class' => ['health', $state]], $content);
     }
diff --git a/library/Vspheredb/Web/Widget/VMotionHeatmap.php b/library/Vspheredb/Web/Widget/VMotionHeatmap.php
index 027b98a9..8c344919 100644
--- a/library/Vspheredb/Web/Widget/VMotionHeatmap.php
+++ b/library/Vspheredb/Web/Widget/VMotionHeatmap.php
@@ -3,16 +3,16 @@
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
 use Icinga\Module\Vspheredb\Db;
+use Zend_Db_Adapter_Abstract;
 use Zend_Db_Select as ZfSelect;
 
 class VMotionHeatmap
 {
-    /** @var \Zend_Db_Adapter_Abstract */
-    protected $db;
+    protected Zend_Db_Adapter_Abstract $db;
 
-    protected $query;
+    protected ?ZfSelect $query = null;
 
-    protected $eventType;
+    protected ?string $eventType = null;
 
     public function __construct(Db $connection)
     {
@@ -24,19 +24,20 @@ public function getEvents(): array
         return $this->db->fetchPairs($this->getQuery());
     }
 
-    public function filterEventType($type): self
+    public function filterEventType(?string $type): static
     {
         $this->eventType = $type;
 
         return $this;
     }
 
-    public function filterParent($uuid): self
+    public function filterParent(string $uuid): static
     {
-        $this->getQuery()->join(['h' => 'object'], $this->db->quoteInto(
-            'h.uuid = veh.host_uuid AND h.parent_uuid = ?',
-            $uuid
-        ), []);
+        $this->getQuery()->join(
+            ['h' => 'object'],
+            $this->db->quoteInto('h.uuid = veh.host_uuid AND h.parent_uuid = ?', $uuid),
+            []
+        );
 
         return $this;
     }
@@ -44,17 +45,17 @@ public function filterParent($uuid): self
     protected function prepareQuery(): ZfSelect
     {
         $maxDays = 400;
-        $query = $this->db->select()->from(['veh' => 'vm_event_history'], [
-            // TODO: / 86400 + offset
-            'day' => 'DATE(FROM_UNIXTIME(veh.ts_event_ms / 1000))',
-            'cnt' => 'COUNT(*)'
-        ])->where('veh.ts_event_ms > ?', time() * 1000 - 86400 * $maxDays * 1000)->group('day');
+        $query = $this->db->select()
+            ->from(['veh' => 'vm_event_history'], [
+                // TODO: / 86400 + offset
+                'day' => 'DATE(FROM_UNIXTIME(veh.ts_event_ms / 1000))',
+                'cnt' => 'COUNT(*)'
+            ])
+            ->where('veh.ts_event_ms > ?', time() * 1000 - 86400 * $maxDays * 1000)
+            ->group('day');
 
         if ($this->eventType !== null && $this->eventType !== '') {
-            $query->where(
-                'veh.event_type = ?',
-                $this->eventType
-            );
+            $query->where('veh.event_type = ?', $this->eventType);
         }
 
         return $query;
@@ -62,10 +63,6 @@ protected function prepareQuery(): ZfSelect
 
     protected function getQuery(): ZfSelect
     {
-        if ($this->query === null) {
-            $this->query = $this->prepareQuery();
-        }
-
-        return $this->query;
+        return $this->query ??= $this->prepareQuery();
     }
 }
diff --git a/library/Vspheredb/Web/Widget/Vm/BackupToolInfo.php b/library/Vspheredb/Web/Widget/Vm/BackupToolInfo.php
index 52f80bdb..00a379db 100644
--- a/library/Vspheredb/Web/Widget/Vm/BackupToolInfo.php
+++ b/library/Vspheredb/Web/Widget/Vm/BackupToolInfo.php
@@ -17,15 +17,14 @@ class BackupToolInfo extends HtmlDocument
 {
     use Translation;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
     public function __construct(VirtualMachine $vm)
     {
         $this->vm = $vm;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $vm = $this->vm;
         $this->add(new SubTitle($this->translate('Backup-Tools'), 'download'));
@@ -40,25 +39,22 @@ protected function assemble()
             }
         }
         if ($seenBackupTools === 0) {
-            $this->add(Html::tag(
-                'p',
-                null,
-                $this->translate('No known backup tool has been used for this VM')
-            ));
+            $this->add(Html::tag('p', null, $this->translate('No known backup tool has been used for this VM')));
         }
     }
 
     /**
      * TODO: Use a hook once the API stabilized
+     *
      * @return BackupTool[]
      */
-    protected function getBackupTools()
+    protected function getBackupTools(): array
     {
         return [
             new IbmSpectrumProtect(),
             new NetBackup(),
             new VeeamBackup(),
-            new VRangerBackup(),
+            new VRangerBackup()
         ];
     }
 }
diff --git a/library/Vspheredb/Web/Widget/VmHardwareTree.php b/library/Vspheredb/Web/Widget/VmHardwareTree.php
index 144fcf41..7abbdb5c 100644
--- a/library/Vspheredb/Web/Widget/VmHardwareTree.php
+++ b/library/Vspheredb/Web/Widget/VmHardwareTree.php
@@ -3,15 +3,15 @@
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
 use gipfl\IcingaWeb2\Link;
-use Icinga\Module\Vspheredb\Db;
+use Icinga\Module\Vspheredb\Db\DbConnection;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\PathLookup;
 use Icinga\Module\Vspheredb\Util;
 use Icinga\Util\Format;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
+use ipl\Html\HtmlElement;
 use ipl\I18n\Translation;
-use Ramsey\Uuid\Uuid;
 
 class VmHardwareTree extends BaseHtmlElement
 {
@@ -21,25 +21,24 @@ class VmHardwareTree extends BaseHtmlElement
 
     protected $defaultAttributes = [
         'class'            => 'tree',
-        'data-base-target' => '_next',
+        'data-base-target' => '_next'
     ];
 
     protected $tree;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    protected $devices = [];
+    protected array $devices = [];
 
-    protected $parents = [];
+    protected array $parents = [];
 
-    protected $children = [];
+    protected array $children = [];
 
-    protected $disks = [];
+    protected array $disks = [];
 
-    protected $nics = [];
+    protected array $nics = [];
 
-    protected $diskPerf;
+    protected ?array $diskPerf = null;
 
     public function __construct(VirtualMachine $vm)
     {
@@ -47,14 +46,14 @@ public function __construct(VirtualMachine $vm)
     }
 
     /**
-     * @return Db
+     * @return DbConnection
      */
-    protected function getDb()
+    protected function getDb(): DbConnection
     {
         return $this->vm->getConnection();
     }
 
-    protected function fetchDisks()
+    protected function fetchDisks(): void
     {
         $connection = $this->getDb();
         $db = $connection->getDbAdapter();
@@ -69,7 +68,7 @@ protected function fetchDisks()
         }
     }
 
-    protected function fetchNics()
+    protected function fetchNics(): void
     {
         $connection = $this->getDb();
         $db = $connection->getDbAdapter();
@@ -84,7 +83,7 @@ protected function fetchNics()
         }
     }
 
-    protected function fetchHardware()
+    protected function fetchHardware(): void
     {
         $this->fetchDisks();
         $this->fetchNics();
@@ -107,7 +106,7 @@ protected function fetchHardware()
         }
     }
 
-    protected function renderDisk($disk, $device, $controller)
+    protected function renderDisk(object $disk, object $device, object $controller): array
     {
         $lookup = new PathLookup($this->getDb()->getDbAdapter());
         $result = [];
@@ -139,57 +138,40 @@ protected function renderDisk($disk, $device, $controller)
             $result[] = Format::bytes($disk->capacity);
         }
 
-        if (false && array_key_exists($scsi, $this->diskPerf)) {
-            $result[] = new CompactInOutSparkline(
-                $this->diskPerf[$scsi][171],
-                $this->diskPerf[$scsi][172]
-            );
-        }
-
         return $result;
     }
 
-    protected function renderNic($nic, $device, $controller)
+    protected function renderNic(object $nic, object $device, object $controller): Link|array
     {
-        $desc = $device->label;
-
         $parts[] = $nic->mac_address;
         if ($device->summary !== $device->label) {
-            // $parts[] = $device->summary;
+             $parts[] = $device->summary;
         }
 
-        $desc = $desc . ': ' . implode(', ', $parts);
-
-        $result = Link::create($desc, '#', null, [
-            'class' => 'icon-sitemap',
-        ]);
+        $result = Link::create(
+            $device->label . ': ' . implode(', ', $parts),
+            '#',
+            null,
+            ['class' => 'icon-sitemap']
+        );
 
-        if ($nic->portgroup_uuid === null) {
-            return $result;
-        } else {
-            return [$result, $this->linkToPortGroup($nic->portgroup_uuid)];
-        }
+        return $nic->portgroup_uuid === null ? $result : [$result, $this->linkToPortGroup($nic->portgroup_uuid)];
     }
 
-    protected function linkToPortGroup($uuid)
+    protected function linkToPortGroup($uuid): string
     {
         $connection = $this->getDb();
         $db = $connection->getDbAdapter();
         $info = $db->fetchRow(
-            $db->select()->from(
-                ['o' => 'object'],
-                [
+            $db->select()
+                ->from(['o' => 'object'], [
                     'uuid'        => 'o.uuid',
                     'object_name' => 'o.object_name',
-                    'cnt_nics'    => 'COUNT(*)',
-                ]
-            )->join(
-                ['vna' => 'vm_network_adapter'],
-                'vna.portgroup_uuid = o.uuid',
-                []
-            )
-            ->where('o.uuid = ?', $connection->quoteBinary($uuid))
-            ->group('o.uuid')
+                    'cnt_nics'    => 'COUNT(*)'
+                ])
+                ->join(['vna' => 'vm_network_adapter'], 'vna.portgroup_uuid = o.uuid', [])
+                ->where('o.uuid = ?', $connection->quoteBinary($uuid))
+                ->group('o.uuid')
         );
 
         if (false === $info) {
@@ -197,16 +179,9 @@ protected function linkToPortGroup($uuid)
         }
 
         return sprintf('%s (%d NICs)', $info->object_name, $info->cnt_nics);
-
-        // TODO:
-        return Link::create(
-            sprintf('%s (%d NICs)', $info->object_name, $info->cnt_nics),
-            'vspheredb/portgroup',
-            Util::uuidParams($info->uuid)
-        );
     }
 
-    protected function fetchDiskPerf()
+    protected function fetchDiskPerf(): array
     {
         $connection = $this->getDb();
         $db = $connection->getDbAdapter();
@@ -216,16 +191,18 @@ protected function fetchDiskPerf()
             "COALESCE(value_minus3, '0')",
             "COALESCE(value_minus2, '0')",
             "COALESCE(value_minus1, '0')",
-            'value_last',
+            'value_last'
         ]) . ')';
 
-        $query = $db->select()->from('counter_300x5', [
-            // 'name' => 'object_uuid',
-            'instance',
-            'counter_key',
-            'value' => $values,
-        ])->where('object_uuid = ?', $connection->quoteBinary($this->vm->get('uuid')))
-        ->where('counter_key IN (?)', [171, 172]);
+        $query = $db->select()
+            ->from('counter_300x5', [
+                // 'name' => 'object_uuid',
+                'instance',
+                'counter_key',
+                'value' => $values
+            ])
+            ->where('object_uuid = ?', $connection->quoteBinary($this->vm->get('uuid')))
+            ->where('counter_key IN (?)', [171, 172]);
 
         $rows = $db->fetchAll($query);
         $result = [];
@@ -238,13 +215,13 @@ protected function fetchDiskPerf()
     }
 
 
-    public function assemble()
+    protected function assemble(): void
     {
         $this->fetchHardware();
         $this->add($this->renderNodes($this->parents));
     }
 
-    protected function renderNodes($nodes, $level = 0)
+    protected function renderNodes(array $nodes, int $level = 0): HtmlElement|array
     {
         $result = [];
         foreach ($nodes as $child) {
@@ -253,12 +230,12 @@ protected function renderNodes($nodes, $level = 0)
 
         if ($level === 0) {
             return $result;
-        } else {
-            return Html::tag('ul', null, $result);
         }
+
+        return Html::tag('ul', null, $result);
     }
 
-    protected function renderNode($device, $level = 0)
+    protected function renderNode(object $device, int $level = 0): HtmlElement
     {
         /** @var int $key */
         $key = $device->hardware_key;
@@ -271,7 +248,7 @@ protected function renderNode($device, $level = 0)
 
         // TODO: get serious:
         // $isNic = array_key_exists($key, $this->nics
-        $isNic = strpos($desc, 'Network') === 0;
+        $isNic = str_starts_with($desc, 'Network');
 
         if ($isDisk) {
             $class = 'icon-database';
@@ -282,12 +259,11 @@ protected function renderNode($device, $level = 0)
         }
 
         $li = Html::tag('li');
-        if (! $hasChildren) {
-            $li->getAttributes()->add('class', 'collapsed');
-        }
 
         if ($hasChildren) {
             $li->add(Html::tag('span', ['class' => 'handle']));
+        } else {
+            $li->getAttributes()->add('class', 'collapsed');
         }
 
         /** @var int|string $controllerKey */
@@ -295,11 +271,11 @@ protected function renderNode($device, $level = 0)
         if ($isDisk) {
             $li->add($this->renderDisk($this->disks[$key], $device, $this->devices[$controllerKey]));
         } elseif ($isNic) {
-            if (array_key_exists($key, $this->nics)) {
-                $li->add($this->renderNic($this->nics[$key], $device, $this->devices[$controllerKey]));
-            } else {
-                $li->add(Link::create($desc, '#', null, ['class' => $class, 'title' => 'No more details available']));
-            }
+            $li->add(
+                array_key_exists($key, $this->nics)
+                    ? $this->renderNic($this->nics[$key], $device, $this->devices[$controllerKey])
+                    : Link::create($desc, '#', null, ['class' => $class, 'title' => 'No more details available'])
+            );
         } else {
             $li->add(Link::create($desc, '#', null, ['class' => $class]));
         }
diff --git a/library/Vspheredb/Web/Widget/VmHeader.php b/library/Vspheredb/Web/Widget/VmHeader.php
index f5609dc4..e2006ca8 100644
--- a/library/Vspheredb/Web/Widget/VmHeader.php
+++ b/library/Vspheredb/Web/Widget/VmHeader.php
@@ -3,6 +3,7 @@
 namespace Icinga\Module\Vspheredb\Web\Widget;
 
 use gipfl\IcingaWeb2\Icon;
+use Icinga\Exception\NotFoundError;
 use Icinga\Module\Vspheredb\Data\Anonymizer;
 use Icinga\Module\Vspheredb\DbObject\VirtualMachine;
 use Icinga\Module\Vspheredb\DbObject\VmQuickStats;
@@ -14,17 +15,13 @@ class VmHeader extends BaseHtmlElement
 {
     use Translation;
 
-    /** @var VirtualMachine */
-    protected $vm;
+    protected VirtualMachine $vm;
 
-    /** @var VmQuickStats */
-    protected $quickStats;
+    protected VmQuickStats $quickStats;
 
     protected $tag = 'div';
 
-    protected $defaultAttributes = [
-        'class' => 'vm-header'
-    ];
+    protected $defaultAttributes = ['class' => 'vm-header'];
 
     public function __construct(VirtualMachine $vm, VmQuickStats $quickStats)
     {
@@ -33,9 +30,9 @@ public function __construct(VirtualMachine $vm, VmQuickStats $quickStats)
     }
 
     /**
-     * @throws \Icinga\Exception\NotFoundError
+     * @throws NotFoundError
      */
-    protected function assemble()
+    protected function assemble(): void
     {
         $vm = $this->vm;
         $vm->object()->set('object_name', Anonymizer::anonymizeString($vm->object()->get('object_name')));
@@ -45,25 +42,17 @@ protected function assemble()
         $powerState = $vm->get('runtime_power_state');
         $renderer = new PowerStateRenderer();
         if ($vm->get('template') === 'y') {
-            $cpu = Html::tag('div', [
-                'class' => 'vm-template'
-            ], Icon::create('upload', [
+            $cpu = Html::tag('div', ['class' => 'vm-template'], Icon::create('upload', [
                 'title' => $this->translate('This is a template'),
-                'class' => [ 'state' ]
+                'class' => ['state']
             ]));
 
             $mem = $this->translate('This is a template');
         } elseif ($powerState !== 'poweredOn') {
-            $cpu = Html::tag('div', [
-                'class' => 'cpu off',
-                // 'style' => 'font-size: 3em; width: 1em; height: 1em; display: inline-block;',
-            ], $renderer($powerState));
+            $cpu = Html::tag('div', ['class' => 'cpu off'], $renderer($powerState));
             $mem = $renderer->getPowerStateDescription($powerState);
         } else {
-            $cpu = new CpuAbsoluteUsage(
-                $this->quickStats->get('overall_cpu_usage'),
-                $vm->get('hardware_numcpu')
-            );
+            $cpu = new CpuAbsoluteUsage($this->quickStats->get('overall_cpu_usage'), $vm->get('hardware_numcpu'));
             $mem = new MemoryUsage(
                 $this->quickStats->get('guest_memory_usage_mb'),
                 $vm->get('hardware_memorymb'),
@@ -71,10 +60,6 @@ protected function assemble()
             );
         }
         $title = Html::tag('h1', $vm->object()->get('object_name'));
-        $this->add([
-            $cpu,
-            $title,
-            $mem
-        ]);
+        $this->add([$cpu, $title, $mem]);
     }
 }
diff --git a/library/Vspheredb/Web/Widget/VmRouteConfigTable.php b/library/Vspheredb/Web/Widget/VmRouteConfigTable.php
index f85daa9d..6b081c5a 100644
--- a/library/Vspheredb/Web/Widget/VmRouteConfigTable.php
+++ b/library/Vspheredb/Web/Widget/VmRouteConfigTable.php
@@ -11,15 +11,14 @@ class VmRouteConfigTable extends HtmlDocument
 {
     use Translation;
 
-    /** @var VirtualMachine */
-    protected $object;
+    protected VirtualMachine $object;
 
     public function __construct(VirtualMachine $object)
     {
         $this->object = $object;
     }
 
-    protected function assemble()
+    protected function assemble(): void
     {
         $object = $this->object;
         $this->prepend(new SubTitle($this->translate('Guest Routing Table'), 'sitemap'));
@@ -29,10 +28,11 @@ protected function assemble()
         } else {
             $table = new Table();
             foreach ($stacks as $stack) {
-                $table->add(Table::row([
-                    $this->translate('Network'),
-                    $this->translate('Gateway')
-                ], ['class' => 'text-left'], 'th'));
+                $table->add(Table::row(
+                    [$this->translate('Network'), $this->translate('Gateway')],
+                    ['class' => 'text-left'],
+                    'th'
+                ));
                 if (! isset($stack->ipRouteConfig->ipRoute)) {
                     continue;
                 }
@@ -48,10 +48,7 @@ protected function assemble()
                     if (empty($gateway)) {
                         $gateway[] = '-';
                     }
-                    $table->add(Table::row([
-                        $route->network . '/' . $route->prefixLength,
-                        implode(', ', $gateway),
-                    ]));
+                    $table->add(Table::row([$route->network . '/' . $route->prefixLength, implode(', ', $gateway)]));
                 }
             }
             $this->add($table);
diff --git a/library/Vspheredb/WebUtil.php b/library/Vspheredb/WebUtil.php
index db2e8360..374ff2f2 100644
--- a/library/Vspheredb/WebUtil.php
+++ b/library/Vspheredb/WebUtil.php
@@ -6,23 +6,21 @@
 use ipl\Html\Error as HtmlError;
 use ipl\Html\Html;
 use ipl\Html\HtmlDocument;
+use ipl\Html\HtmlElement;
 use Throwable;
-use Exception;
 
 class WebUtil
 {
-    public static function runFailSafe($callback, HtmlDocument $parent)
+    public static function runFailSafe(callable $callback, HtmlDocument $parent): void
     {
         try {
             $callback();
-        } catch (Exception $e) {
-            $parent->add(HtmlError::show($e));
         } catch (Throwable $e) {
             $parent->add(HtmlError::show($e));
         }
     }
 
-    public static function timeAgo($time)
+    public static function timeAgo(float|int $time): HtmlElement
     {
         return Html::tag('span', [
             'class' => 'time-ago',
diff --git a/run-missingdeps.php b/run-missingdeps.php
deleted file mode 100644
index e110feea..00000000
--- a/run-missingdeps.php
+++ /dev/null
@@ -1,23 +0,0 @@
-<?php
-
-use Icinga\Application\Icinga;
-use Icinga\Exception\IcingaException;
-use Icinga\Web\Url;
-
-if (Icinga::app()->isCli()) {
-    throw new IcingaException(
-        "Missing dependencies, please check "
-    );
-} else {
-    $request = Icinga::app()->getRequest();
-    $path = $request->getPathInfo();
-    if (! preg_match('#^/vspheredb#', $path)) {
-        return;
-    }
-    if (preg_match('#^/vspheredb/phperror/dependencies#', $path)) {
-        return;
-    }
-
-    header('Location: ' . Url::fromPath('vspheredb/phperror/dependencies'));
-    exit;
-}
diff --git a/run.php b/run.php
index 0f19e5f7..39b1e30a 100644
--- a/run.php
+++ b/run.php
@@ -1,17 +1,9 @@
 <?php
 
 use Icinga\Application\Modules\Module;
-use Icinga\Module\Vspheredb\Application\DependencyChecker;
 use Icinga\Module\Vspheredb\ProvidedHook\Director\DataTypeMonitoringRule;
 use Icinga\Module\Vspheredb\ProvidedHook\Vspheredb\PerfDataConsumerInfluxDb;
 
-/** @var $this \Icinga\Application\Modules\Module */
-$checker = new DependencyChecker($this->app);
-if (! $checker->satisfiesDependencies($this)) {
-    include __DIR__ . '/run-missingdeps.php';
-    return;
-}
-
 $this->provideHook('director/ImportSource');
 $this->provideHook('director/DataType', DataTypeMonitoringRule::class);
 $this->provideHook('vspheredb/PerfDataConsumer', PerfDataConsumerInfluxDb::class);