diff --git a/agent/Makefile.frag b/agent/Makefile.frag
index c54a8cb0a..81e909637 100644
--- a/agent/Makefile.frag
+++ b/agent/Makefile.frag
@@ -202,10 +202,21 @@ endif
 # prefer the static version if it's available, but depending on how PHP was
 # installed, we may only have the shared version.
 #
-ifneq (,$(wildcard $(libdir)/libphp$(shell $(PHP_CONFIG) --version | cut -d . -f 1).a))
-	PHP_EMBED_LIBRARY := $(libdir)/libphp$(shell $(PHP_CONFIG) --version | cut -d . -f 1).a
+
+
+# Update for PHP8:
+# They no longer adhere to their prior versioning system.  The library is now
+# simply $prefix/lib/libphp.{a,so}
+
+major = $(shell $(PHP_CONFIG) --version | cut -d . -f 1)
+ifeq ($(major), 8)
+    major =
+endif
+
+ifneq (,$(wildcard $(libdir)/libphp$(major).a))
+	PHP_EMBED_LIBRARY := $(libdir)/libphp$(major).a
 else
-	PHP_EMBED_LIBRARY := $(libdir)/libphp$(shell $(PHP_CONFIG) --version | cut -d . -f 1).so
+	PHP_EMBED_LIBRARY := $(libdir)/libphp$(major).so
 endif
 
 #
diff --git a/agent/fw_laravel.c b/agent/fw_laravel.c
index 5777c188d..1251fae8c 100644
--- a/agent/fw_laravel.c
+++ b/agent/fw_laravel.c
@@ -109,7 +109,8 @@ static PHP_NAMED_FUNCTION(nr_laravel_afterfilter_construct) {
       /*
        * It's a valid app object. Set $this->app to contain it.
        */
-      zend_update_property(nr_laravel_afterfilter_ce, this_obj, NR_PSTR("app"),
+      zend_update_property(nr_laravel_afterfilter_ce,
+                           ZVAL_OR_ZEND_OBJECT(this_obj), NR_PSTR("app"),
                            app TSRMLS_CC);
     } else {
       /*
diff --git a/agent/fw_laravel_queue.c b/agent/fw_laravel_queue.c
index a0025041c..d038936a6 100644
--- a/agent/fw_laravel_queue.c
+++ b/agent/fw_laravel_queue.c
@@ -558,7 +558,7 @@ NR_PHP_WRAPPER(nr_laravel_queue_worker_process) {
   if (EG(exception)) {
     zval* exception_zval = NULL;
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
     /*
      * On PHP 7, EG(exception) is stored as a zend_object, and is only wrapped
      * in a zval when it actually needs to be. Unfortunately, our error handling
@@ -583,7 +583,7 @@ NR_PHP_WRAPPER(nr_laravel_queue_worker_process) {
      * On PHP 5, the exception is just a regular old zval.
      */
     exception_zval = EG(exception);
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
     nr_php_error_record_exception(
         NRPRG(txn), exception_zval, NR_PHP_ERROR_PRIORITY_UNCAUGHT_EXCEPTION,
@@ -748,7 +748,8 @@ NR_PHP_WRAPPER(nr_laravel_queue_queue_createpayload) {
     header_mq = nr_laravel_get_payload_header_mq(header);
 
     if (header_mq) {
-      zend_update_property_string(Z_OBJCE_P(payload), payload, header_mq,
+      zend_update_property_string(Z_OBJCE_P(payload),
+                                  ZVAL_OR_ZEND_OBJECT(payload), header_mq,
                                   nr_strlen(header_mq), value TSRMLS_CC);
     }
   }
@@ -761,13 +762,13 @@ NR_PHP_WRAPPER(nr_laravel_queue_queue_createpayload) {
   /*
    * Finally, we change the string in the return value to our new JSON.
    */
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   zend_string_free(Z_STR_P(*retval_ptr));
   Z_STR_P(*retval_ptr) = zend_string_copy(Z_STR_P(json));
 #else
   efree(Z_STRVAL_PP(retval_ptr));
   nr_php_zval_str_len(*retval_ptr, Z_STRVAL_P(json), Z_STRLEN_P(json));
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
 end:
   nr_php_zval_free(&payload);
diff --git a/agent/lib_guzzle6.c b/agent/lib_guzzle6.c
index 02216b67b..45cfca5ab 100644
--- a/agent/lib_guzzle6.c
+++ b/agent/lib_guzzle6.c
@@ -203,8 +203,8 @@ static PHP_NAMED_FUNCTION(nr_guzzle6_requesthandler_construct) {
     return;
   }
 
-  zend_update_property(Z_OBJCE_P(this_obj), this_obj, NR_PSTR("request"),
-                       request TSRMLS_CC);
+  zend_update_property(Z_OBJCE_P(this_obj), ZVAL_OR_ZEND_OBJECT(this_obj),
+                       NR_PSTR("request"), request TSRMLS_CC);
 
   nr_guzzle_obj_add(this_obj, "Guzzle 6" TSRMLS_CC);
 }
diff --git a/agent/php_agent.c b/agent/php_agent.c
index 7ace7c010..0e8882d1d 100644
--- a/agent/php_agent.c
+++ b/agent/php_agent.c
@@ -17,7 +17,7 @@ static zval* nr_php_get_zval_object_property_with_class_internal(
     zval* object,
     zend_class_entry* ce,
     const char* cname TSRMLS_DC) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   /*
    * Although the below notes still apply in principle, PHP 7 additionally broke
    * the API for zend_read_property by adding an rv parameter, which is used to
@@ -33,7 +33,8 @@ static zval* nr_php_get_zval_object_property_with_class_internal(
   zval rv;
   zend_bool silent = 1;
 
-  data = zend_read_property(ce, object, cname, nr_strlen(cname), silent, &rv);
+  data = zend_read_property(ce, ZVAL_OR_ZEND_OBJECT(object), cname,
+                            nr_strlen(cname), silent, &rv);
   if (&EG(uninitialized_zval) != data) {
     return data;
   }
@@ -55,7 +56,7 @@ static zval* nr_php_get_zval_object_property_with_class_internal(
   if (EG(uninitialized_zval_ptr) != data) {
     return data;
   }
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
   return NULL;
 }
@@ -124,7 +125,7 @@ int nr_php_object_has_method(zval* object, const char* lcname TSRMLS_DC) {
     } else {
       void* func;
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
       zend_string* name_str = zend_string_init(vname, namelen, 0);
 
       func = (void*)Z_OBJ_HT_P(object)->get_method(&Z_OBJ_P(object), name_str,
@@ -188,7 +189,7 @@ zend_function* nr_php_find_function(const char* name TSRMLS_DC) {
  * whereas PHP 7 only uses a single level of indirection.
  */
 zend_class_entry* nr_php_find_class(const char* name TSRMLS_DC) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   if (NULL == name) {
     return NULL;
   }
@@ -204,7 +205,7 @@ zend_class_entry* nr_php_find_class(const char* name TSRMLS_DC) {
   ce_ptr = (zend_class_entry**)nr_php_zend_hash_find_ptr(EG(class_table), name);
 
   return ce_ptr ? *ce_ptr : NULL;
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 zend_function* nr_php_find_class_method(const zend_class_entry* klass,
@@ -260,7 +261,7 @@ zend_function* nr_php_zval_to_function(zval* zv TSRMLS_DC) {
     return NULL;
   }
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   if (zend_is_callable_ex(zv, NULL, 0, NULL, &fcc, NULL)) {
     return fcc.function_handler;
   }
@@ -268,7 +269,7 @@ zend_function* nr_php_zval_to_function(zval* zv TSRMLS_DC) {
   if (zend_is_callable_ex(zv, NULL, 0, NULL, NULL, &fcc, NULL TSRMLS_CC)) {
     return fcc.function_handler;
   }
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
   return NULL;
 }
@@ -319,8 +320,8 @@ zend_execute_data* nr_get_zend_execute_data(NR_EXECUTE_PROTO TSRMLS_DC) {
  *
  * See the picture near line 1525 of PHP 5.5.3 zend_execute.c
  */
-#if ZEND_MODULE_API_NO >= ZEND_5_5_X_API_NO \
-    && !defined(PHP7) /* PHP 5.5 and 5.6 */
+#if ZEND_MODULE_API_NO >= ZEND_5_5_X_API_NO && !defined(PHP7) \
+    && !defined(PHP8) /* PHP 5.5 and 5.6 */
 static void** nr_php_get_php55_stack_arguments(int legitimate_frame_delta,
                                                NR_EXECUTE_PROTO TSRMLS_DC) {
   zend_execute_data* ex;
@@ -358,7 +359,7 @@ static void** nr_php_get_php55_stack_arguments(int legitimate_frame_delta,
 }
 #endif
 
-#ifndef PHP7
+#if !defined(PHP7) && !defined(PHP8) /* PHP 5.5 and 5.6 */
 /*
  * Use detailed zend specific knowledge of the interpreter stack
  * to read the argument vector.
@@ -408,7 +409,7 @@ static zval* nr_php_get_user_func_arg_via_h(int requested_arg_index,
   arg = *argp;
   return arg;
 }
-#endif /* !PHP7 */
+#endif /* !PHP7 && !PHP8*/
 
 /*
  * NOTICE: requested_arg_index is a 1-based value, not a 0-based value!
@@ -422,7 +423,7 @@ zval* nr_php_get_user_func_arg(size_t requested_arg_index,
     return NULL;
   }
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   (void)arg_count_via_h;
 
   if (requested_arg_index > ZEND_CALL_NUM_ARGS(execute_data)) {
@@ -433,13 +434,13 @@ zval* nr_php_get_user_func_arg(size_t requested_arg_index,
 #else
   arg_via_h = nr_php_get_user_func_arg_via_h(
       requested_arg_index, &arg_count_via_h, NR_EXECUTE_ORIG_ARGS TSRMLS_CC);
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
   return arg_via_h;
 }
 
 size_t nr_php_get_user_func_arg_count(NR_EXECUTE_PROTO TSRMLS_DC) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return (size_t)ZEND_CALL_NUM_ARGS(execute_data);
 #else
   int arg_count_via_h = -1;
@@ -455,7 +456,7 @@ size_t nr_php_get_user_func_arg_count(NR_EXECUTE_PROTO TSRMLS_DC) {
   }
 
   return (size_t)arg_count_via_h;
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 zend_execute_data* nr_php_get_caller_execute_data(NR_EXECUTE_PROTO,
@@ -484,7 +485,7 @@ zend_execute_data* nr_php_get_caller_execute_data(NR_EXECUTE_PROTO,
     ced = ced->prev_execute_data;
   }
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   if ((NULL == ced) || (NULL == ced->opline)) {
     return NULL;
   }
@@ -492,14 +493,14 @@ zend_execute_data* nr_php_get_caller_execute_data(NR_EXECUTE_PROTO,
   if ((NULL == ced) || (NULL == ced->op_array)) {
     return NULL;
   }
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
   if ((ZEND_DO_FCALL != ced->opline->opcode)
       && (ZEND_DO_FCALL_BY_NAME != ced->opline->opcode)) {
     return NULL;
   }
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   if (NULL == ced->func) {
     return NULL;
   }
@@ -507,7 +508,7 @@ zend_execute_data* nr_php_get_caller_execute_data(NR_EXECUTE_PROTO,
   if (0 == ced->function_state.function) {
     return NULL;
   }
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
   return ced;
 }
@@ -521,17 +522,17 @@ const zend_function* nr_php_get_caller(NR_EXECUTE_PROTO,
     return NULL;
   }
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return ped->func;
 #else
   return ped->function_state.function;
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 zval* nr_php_get_active_php_variable(const char* name TSRMLS_DC) {
   HashTable* table;
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   table = zend_rebuild_symbol_table();
 
   /*
@@ -548,7 +549,7 @@ zval* nr_php_get_active_php_variable(const char* name TSRMLS_DC) {
 #else
   table = EG(active_symbol_table);
   return nr_php_zend_hash_find(table, name);
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 int nr_php_silence_errors(TSRMLS_D) {
@@ -564,7 +565,7 @@ void nr_php_restore_errors(int error_reporting TSRMLS_DC) {
 }
 
 zval* nr_php_get_constant(const char* name TSRMLS_DC) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   zval* constant;
   zval* copy = NULL;
   zend_string* name_str;
@@ -608,7 +609,7 @@ zval* nr_php_get_constant(const char* name TSRMLS_DC) {
   }
 
   return constant;
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 zval* nr_php_get_class_constant(const zend_class_entry* ce, const char* name) {
@@ -674,7 +675,7 @@ int nr_php_is_zval_named_constant(const zval* zv, const char* name TSRMLS_DC) {
 }
 
 int nr_php_zend_is_auto_global(const char* name, size_t name_len TSRMLS_DC) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   zend_bool rv;
   zend_string* zs = zend_string_init(name, name_len, 0);
 
@@ -684,7 +685,7 @@ int nr_php_zend_is_auto_global(const char* name, size_t name_len TSRMLS_DC) {
   return rv;
 #else
   return (int)zend_is_auto_global(name, (int)name_len TSRMLS_CC);
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 const char* nr_php_use_license(const char* api_license TSRMLS_DC) {
@@ -712,7 +713,7 @@ char* nr_php_get_server_global(const char* name TSRMLS_DC) {
     return NULL;
   }
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   global = &(PG(http_globals)[TRACK_VARS_SERVER]);
 #else
   global = PG(http_globals)[TRACK_VARS_SERVER];
@@ -942,12 +943,12 @@ void nr_php_remove_interface_from_class(zend_class_entry* class_ce,
     }
   }
 
-    /*
-     * We have to discard the const qualifier on the interface class entry to
-     * pass it through to nr_php_zend_hash_ptr_apply, even though the apply
-     * callback itself takes a const zend_class_entry *. Since this generates a
-     * warning in gcc, we'll squash it.
-     */
+  /*
+   * We have to discard the const qualifier on the interface class entry to
+   * pass it through to nr_php_zend_hash_ptr_apply, even though the apply
+   * callback itself takes a const zend_class_entry *. Since this generates a
+   * warning in gcc, we'll squash it.
+   */
 #if defined(__clang__) || (__GNUC__ > 4) \
     || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 5))
 #pragma GCC diagnostic push
@@ -1039,11 +1040,11 @@ char* nr_php_function_debug_name(const zend_function* func) {
 
   if ((ZEND_USER_FUNCTION == func->type)
       && (func->common.fn_flags & ZEND_ACC_CLOSURE)) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
     const char* filename = ZSTR_VAL(func->op_array.filename);
 #else
     const char* filename = func->op_array.filename;
-#endif /* PHP7 */
+#endif /* PHP7+ */
     char* orig_name = name;
 
     name = nr_formatf("%s declared at %s:%d", orig_name, NRSAFESTR(filename),
diff --git a/agent/php_agent.h b/agent/php_agent.h
index ff2130ddd..69bd08039 100644
--- a/agent/php_agent.h
+++ b/agent/php_agent.h
@@ -330,7 +330,7 @@ extern zend_function* nr_php_zval_to_function(zval* zv TSRMLS_DC);
  *           won't help you!
  */
 static inline zval* nr_php_get_return_value(NR_EXECUTE_PROTO TSRMLS_DC) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   if (NULL == execute_data) {
     /*
      * This function shouldn't be called from outside a function context, so
@@ -346,7 +346,7 @@ static inline zval* nr_php_get_return_value(NR_EXECUTE_PROTO TSRMLS_DC) {
   NR_UNUSED_SPECIALFN;
 
   return return_value_ptr_ptr ? *return_value_ptr_ptr : NULL;
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 /*
@@ -358,7 +358,7 @@ static inline zval* nr_php_get_return_value(NR_EXECUTE_PROTO TSRMLS_DC) {
  *           other "should not happen" situation. Note that this may be an
  *           IS_REFERENCE zval in PHP 7 if the function expects a reference.
  *
- * Warning : Directly modifying the returned zval in PHP 7 may result in 
+ * Warning : Directly modifying the returned zval in PHP 7 may result in
  *           difficult issues that are difficult to debug.
  *
  * IMPORTANT : This should only be called before the call to the current user
@@ -389,14 +389,14 @@ static inline zend_function* nr_php_execute_function(
   }
 #endif
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return execute_data->func;
 #elif ZEND_MODULE_API_NO >= ZEND_5_5_X_API_NO
   return execute_data->function_state.function;
 #else
   return op_array_arg->prototype ? op_array_arg->prototype
                                  : (zend_function*)op_array_arg;
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 static inline zval* nr_php_execute_scope(zend_execute_data* execute_data) {
@@ -404,7 +404,7 @@ static inline zval* nr_php_execute_scope(zend_execute_data* execute_data) {
     return NULL;
   }
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return &execute_data->This;
 #else
   return execute_data->object;
@@ -600,26 +600,26 @@ extern const char* nr_php_function_filename(zend_function* func);
 static inline zend_class_entry* nr_php_zend_register_internal_class_ex(
     zend_class_entry* ce,
     zend_class_entry* parent_ce TSRMLS_DC) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return zend_register_internal_class_ex(ce, parent_ce);
 #else
   return zend_register_internal_class_ex(ce, parent_ce, NULL TSRMLS_CC);
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 static inline char* nr_php_zend_ini_string(char* name,
                                            nr_string_len_t name_len,
                                            int orig) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return zend_ini_string(name, name_len, orig);
 #else
   return zend_ini_string(name, name_len + 1, orig);
-#endif /* PHP7 */
+#endif /* PHP7+ */
 }
 
 static inline const char* NRPURE
 nr_php_class_entry_name(const zend_class_entry* ce) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return (ce->name && ce->name->len) ? ce->name->val : NULL;
 #else
   return ce->name;
@@ -628,7 +628,7 @@ nr_php_class_entry_name(const zend_class_entry* ce) {
 
 static inline nr_string_len_t NRPURE
 nr_php_class_entry_name_length(const zend_class_entry* ce) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return ce->name ? ce->name->len : 0;
 #else
   return NRSAFELEN(ce->name_length);
@@ -637,7 +637,7 @@ nr_php_class_entry_name_length(const zend_class_entry* ce) {
 
 static inline const char* NRPURE
 nr_php_function_name(const zend_function* func) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return (func->common.function_name && func->common.function_name->len)
              ? func->common.function_name->val
              : NULL;
@@ -648,7 +648,7 @@ nr_php_function_name(const zend_function* func) {
 
 static inline nr_string_len_t NRPURE
 nr_php_function_name_length(const zend_function* func) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return func->common.function_name ? func->common.function_name->len : 0;
 #else
   /*
@@ -661,7 +661,7 @@ nr_php_function_name_length(const zend_function* func) {
 
 static inline const char* NRPURE
 nr_php_op_array_file_name(const zend_op_array* op_array) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return (op_array->filename && op_array->filename->len)
              ? op_array->filename->val
              : NULL;
@@ -672,7 +672,7 @@ nr_php_op_array_file_name(const zend_op_array* op_array) {
 
 static inline const char* NRPURE
 nr_php_op_array_function_name(const zend_op_array* op_array) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return (op_array->function_name && op_array->function_name->len)
              ? op_array->function_name->val
              : NULL;
@@ -683,7 +683,7 @@ nr_php_op_array_function_name(const zend_op_array* op_array) {
 
 static inline const char* NRPURE
 nr_php_op_array_scope_name(const zend_op_array* op_array) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   if (op_array->scope && op_array->scope->name && op_array->scope->name->len) {
     return op_array->scope->name->val;
   }
@@ -698,7 +698,7 @@ nr_php_op_array_scope_name(const zend_op_array* op_array) {
 
 static inline const char* NRPURE
 nr_php_ini_entry_name(const zend_ini_entry* entry) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return (entry->name && entry->name->len) ? entry->name->val : NULL;
 #else
   return entry->name;
@@ -706,7 +706,7 @@ nr_php_ini_entry_name(const zend_ini_entry* entry) {
 }
 static inline nr_string_len_t NRPURE
 nr_php_ini_entry_name_length(const zend_ini_entry* entry) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   return entry->name ? entry->name->len : 0;
 #else
   return NRSAFELEN(entry->name_length - 1);
@@ -715,11 +715,18 @@ nr_php_ini_entry_name_length(const zend_ini_entry* entry) {
 
 #define NR_PHP_INTERNAL_FN_THIS() getThis()
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
 #define NR_PHP_USER_FN_THIS() getThis()
 #else
 #define NR_PHP_USER_FN_THIS() EG(This)
-#endif
+#endif /* PHP 7.0+ */
+
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO /* PHP 8.0+ */
+/* PHP 8 expects zend_object not zval */
+#define ZVAL_OR_ZEND_OBJECT(x) Z_OBJ(*x)
+#else
+#define ZVAL_OR_ZEND_OBJECT(x) x
+#endif /* PHP8+ */
 
 /*
  * Purpose : Wrap the native PHP json_decode function for those times when we
diff --git a/agent/php_api_distributed_trace.c b/agent/php_api_distributed_trace.c
index 3173d8a9c..27248b33a 100644
--- a/agent/php_api_distributed_trace.c
+++ b/agent/php_api_distributed_trace.c
@@ -317,10 +317,10 @@ PHP_FUNCTION(newrelic_create_distributed_trace_payload) {
         NRPRG(txn), nr_txn_get_current_segment(NRPRG(txn), NULL));
 
     if (payload) {
-      zend_update_property_string(nr_distributed_trace_payload_ce, return_value,
-                                  nr_remove_const(payload_text_prop),
-                                  sizeof(payload_text_prop) - 1,
-                                  payload TSRMLS_CC);
+      zend_update_property_string(
+          nr_distributed_trace_payload_ce, ZVAL_OR_ZEND_OBJECT(return_value),
+          nr_remove_const(payload_text_prop), sizeof(payload_text_prop) - 1,
+          payload TSRMLS_CC);
       nr_free(payload);
     }
   }
@@ -384,7 +384,7 @@ PHP_FUNCTION(newrelic_insert_distributed_trace_headers) {
   tracestate = nr_txn_create_w3c_tracestate_header(
       NRPRG(txn), nr_txn_get_current_segment(NRPRG(txn), NULL));
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   SEPARATE_ARRAY(header_array);
 #endif /* PHP7 */
 
diff --git a/agent/php_call.c b/agent/php_call.c
index 2e261bc36..f268fc59a 100644
--- a/agent/php_call.c
+++ b/agent/php_call.c
@@ -14,13 +14,15 @@ zval* nr_php_call_user_func(zval* object_ptr,
                             const char* function_name,
                             zend_uint param_count,
                             zval* params[] TSRMLS_DC) {
-#ifdef PHP7
-  int zend_result;
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
+  int zend_result = FAILURE;
   zval* fname = NULL;
-  int no_separation = 0;
   HashTable* symbol_table = NULL;
   zval* param_values = NULL;
   zval* retval = NULL;
+#ifndef PHP8
+  int no_separation = 0;
+#endif /* PHP8 */
 
   /*
    * Prevent an unused variable warning. PHP 7.1 changed call_user_function_ex
@@ -46,9 +48,20 @@ zval* nr_php_call_user_func(zval* object_ptr,
 
   fname = nr_php_zval_alloc();
   nr_php_zval_str(fname, function_name);
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO /* PHP 8.0+ */
+
+  /*
+   * With PHP8, `call_user_function_ex` was removed and `call_user_function`
+   * became the recommended function.
+   */
+  zend_result = call_user_function(EG(function_table), object_ptr, fname,
+                                   retval, param_count, param_values);
+
+#else
   zend_result = call_user_function_ex(EG(function_table), object_ptr, fname,
                                       retval, param_count, param_values,
                                       no_separation, symbol_table TSRMLS_CC);
+#endif /* PHP8+ */
   nr_php_zval_free(&fname);
 
   nr_free(param_values);
@@ -59,7 +72,7 @@ zval* nr_php_call_user_func(zval* object_ptr,
 
   nr_php_zval_free(&retval);
   return NULL;
-#else
+#else /* PHP < 7 */
   int zend_result;
   zval* fname = NULL;
   int no_separation = 0;
@@ -114,14 +127,14 @@ zval* nr_php_call_user_func_catch(zval* object_ptr,
   }
 
   /*
-   * The approach for both PHP 5 and 7 is conceptually the same: persist the
+   * The approach for both PHP 5, 7, and 8 is conceptually the same: persist the
    * current exception pointer in the executor globals, then compare it after
    * the call has been made. If the pointer changes, then an exception was
-   * thrown. The key difference is that PHP 5 uses a zval, whereas PHP 7 uses
+   * thrown. The key difference is that PHP 5 uses a zval, whereas PHP 7+ uses
    * a zend_object.
    */
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   {
     zend_object* exception_obj = EG(exception);
 
@@ -157,7 +170,7 @@ zval* nr_php_call_user_func_catch(zval* object_ptr,
       zend_clear_exception(TSRMLS_C);
     }
   }
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
   return retval;
 }
diff --git a/agent/php_compat.h b/agent/php_compat.h
index 5916a2b9f..ef727e66a 100644
--- a/agent/php_compat.h
+++ b/agent/php_compat.h
@@ -6,6 +6,10 @@
 #ifndef PHP_COMPAT_HDR
 #define PHP_COMPAT_HDR
 
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO /* PHP 8.0+ */
+#define PHP8
+#endif /* PHP 8.0+ */
+
 #if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
 #define PHP7
 
@@ -85,10 +89,10 @@ static inline zval* nr_php_zval_direct(zval* zv) {
   return zv;
 }
 
-  /*
-   * Reimplement some of the macros that PHP 7 defines to make iteration easier.
-   * For now, only the macros we actually need are implemented.
-   */
+/*
+ * Reimplement some of the macros that PHP 7 defines to make iteration easier.
+ * For now, only the macros we actually need are implemented.
+ */
 
 #define ZEND_HASH_FOREACH(ht)                                              \
   do {                                                                     \
diff --git a/agent/php_error.c b/agent/php_error.c
index fcb51290c..063f11d38 100644
--- a/agent/php_error.c
+++ b/agent/php_error.c
@@ -444,25 +444,38 @@ static int nr_php_should_record_error(int type, const char* format TSRMLS_DC) {
 
   return 1;
 }
-
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO
+void nr_php_error_cb(int type,
+                     const char* error_filename,
+                     uint error_lineno,
+                     zend_string* message) {
+#else
 void nr_php_error_cb(int type,
                      const char* error_filename,
                      uint error_lineno,
                      const char* format,
                      va_list args) {
+#endif /* PHP >= 8.0 */
   TSRMLS_FETCH();
+  char* stack_json = NULL;
+  const char* errclass = NULL;
+  char* msg = NULL;
 
+#if ZEND_MODULE_API_NO < ZEND_8_0_X_API_NO
   if (nr_php_should_record_error(type, format TSRMLS_CC)) {
     va_list args2;
-    char* stack_json = NULL;
-    const char* errclass = NULL;
-    char* msg = NULL;
     int len;
 
     va_copy(args2, args);
     len = vasprintf(&msg, format, args2);
     msg[len] = '\0';
 
+#else
+  if (nr_php_should_record_error(type, ZSTR_VAL(message))) {
+    msg = nr_strdup(ZSTR_VAL(message));
+
+#endif /* PHP < 8.0 */
+
     stack_json = nr_php_backtrace_to_json(0 TSRMLS_CC);
     errclass = get_error_type_string(type);
 
@@ -477,8 +490,13 @@ void nr_php_error_cb(int type,
    * Call through to the actual error handler.
    */
   if (0 != NR_PHP_PROCESS_GLOBALS(orig_error_cb)) {
+#if ZEND_MODULE_API_NO < ZEND_8_0_X_API_NO
     NR_PHP_PROCESS_GLOBALS(orig_error_cb)
     (type, error_filename, error_lineno, format, args);
+#else
+    NR_PHP_PROCESS_GLOBALS(orig_error_cb)
+    (type, error_filename, error_lineno, message);
+#endif /* PHP < 8.0 */
   }
 }
 
@@ -590,11 +608,10 @@ nr_status_t nr_php_error_record_exception_segment(nrtxn_t* txn,
 
   ce = Z_OBJCE_P(exception);
   klass = nr_strndup(ZEND_STRING_VALUE(ce->name), ZEND_STRING_LEN(ce->name));
-  zend_err_file =
-      nr_php_get_zval_object_property(exception, "file" TSRMLS_CC);
+  zend_err_file = nr_php_get_zval_object_property(exception, "file" TSRMLS_CC);
   file = nr_strndup(Z_STRVAL_P(zend_err_file), Z_STRLEN_P(zend_err_file));
-  zend_err_message =
-      nr_php_get_zval_object_property(exception, "message" TSRMLS_CC);
+  zend_err_message
+      = nr_php_get_zval_object_property(exception, "message" TSRMLS_CC);
   message
       = nr_strndup(Z_STRVAL_P(zend_err_message), Z_STRLEN_P(zend_err_message));
   zend_err_line = nr_php_get_zval_object_property(exception, "line" TSRMLS_CC);
diff --git a/agent/php_file_get_contents.c b/agent/php_file_get_contents.c
index ac35f8600..bc85b0436 100644
--- a/agent/php_file_get_contents.c
+++ b/agent/php_file_get_contents.c
@@ -469,7 +469,7 @@ nr_status_t nr_php_file_get_contents_recurse_with_context(
   nr_php_zval_free(&context);
   if (rval) {
     ZVAL_ZVAL(return_value, rval, 0, 1);
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
     /*
      * Calling ZVAL_ZVAL with dtor set to true in PHP 7 won't free the
      * surrounding wrapper.
diff --git a/agent/php_hash.h b/agent/php_hash.h
index baceb0aac..f808af370 100644
--- a/agent/php_hash.h
+++ b/agent/php_hash.h
@@ -122,13 +122,18 @@ nr_php_zend_hash_key_string_value(const zend_hash_key* hash_key) {
 static inline int nr_php_add_assoc_zval(zval* arr,
                                         const char* key,
                                         zval* value) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   zval copy;
 
   ZVAL_DUP(&copy, value);
 
-  return add_assoc_zval(arr, key, &copy);
+#ifdef PHP8
+  add_assoc_zval(arr, key, &copy);
+  return 0;
 #else
+  return add_assoc_zval(arr, key, &copy);
+#endif /* PHP8 */
+#else  /* Less than PHP7 */
   zval* copy;
 
   ALLOC_ZVAL(copy);
diff --git a/agent/php_hooks.h b/agent/php_hooks.h
index 0df230f05..d42aa55a7 100644
--- a/agent/php_hooks.h
+++ b/agent/php_hooks.h
@@ -29,15 +29,38 @@ extern void nr_php_execute(NR_EXECUTE_PROTO TSRMLS_DC);
  *           3. The line number the error occurred on.
  *           4. The format type of the error message.
  *           5. The args that combine to get the error message.
+ *
+ * Notes:
+ *
+ * PHP8 changed how this is handled.
+ * Error notifications have a new API.  Instead of overwriting zend_error_cb
+ * extensions with debugging, monitoring use-cases catching Errors/Exceptions
+ * are strongly encouraged to use the new error notification API instead.
+ * Error notification callbacks are guaranteed to be called regardless of the
+ * users error_reporting setting or userland error handler return values.
+ * Register notification callbacks during MINIT of an extension:
+void my_error_notify_cb(int type,
+                const char *error_filename,
+                        uint32_t error_lineno,
+                        zend_string *message) {
+                }
+                zend_register_error_notify_callback(my_error_notify_cb);
  */
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO
+extern void nr_php_error_cb(int type,
+                            const char* filename,
+                            uint error_lineno,
+                            zend_string* message);
+#else
 extern void nr_php_error_cb(int type,
                             const char* filename,
                             uint error_lineno,
                             const char* fmt,
                             va_list args)
     ZEND_ATTRIBUTE_PTR_FORMAT(printf, 4, 0);
+#endif /* PHP >= 8.0 */
 
-#if defined(PHP7)
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
 extern void nr_php_execute_internal(zend_execute_data* execute_data,
                                     zval* return_value);
 #elif ZEND_MODULE_API_NO >= ZEND_5_5_X_API_NO
diff --git a/agent/php_includes.h b/agent/php_includes.h
index aec4fcead..209ccfe51 100644
--- a/agent/php_includes.h
+++ b/agent/php_includes.h
@@ -49,6 +49,7 @@
 #define ZEND_7_2_X_API_NO 20170718
 #define ZEND_7_3_X_API_NO 20180731
 #define ZEND_7_4_X_API_NO 20190902
+#define ZEND_8_0_X_API_NO 20200930
 
 #if ZEND_MODULE_API_NO >= ZEND_5_6_X_API_NO
 #include "Zend/zend_virtual_cwd.h"
@@ -60,4 +61,17 @@
 #include "TSRM.h"
 #endif
 
+/*
+ * The TSRMLS_* functions included below have actually been voided out since PHP
+ * 7.0.  They were formally removed in PHP 8.0 but we still support in our code,
+ * so we need to add the voided out macros here.
+ */
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO
+#define TSRMLS_D void
+#define TSRMLS_DC
+#define TSRMLS_C
+#define TSRMLS_CC
+#define TSRMLS_FETCH()
+#endif
+
 #endif /* PHP_INCLUDES_HDR */
diff --git a/agent/php_internal_instrument.c b/agent/php_internal_instrument.c
index 382967134..8248934eb 100644
--- a/agent/php_internal_instrument.c
+++ b/agent/php_internal_instrument.c
@@ -134,7 +134,7 @@ static void nr_php_instrument_delegate(nrinternalfn_t* wraprec,
   }
 #else
 #define NR_OUTER_WRAPPER(RAW)                                     \
-  static nrinternalfn_t* NR_OUTER_GLOBAL_NAME(RAW) = NULL;           \
+  static nrinternalfn_t* NR_OUTER_GLOBAL_NAME(RAW) = NULL;        \
   static void ZEND_FASTCALL NR_OUTER_WRAPPER_NAME(RAW)(           \
       INTERNAL_FUNCTION_PARAMETERS) {                             \
     nr_php_instrument_delegate(NR_OUTER_GLOBAL_NAME(RAW),         \
@@ -231,11 +231,25 @@ void nr_php_wrap_internal_function(nrinternalfn_t* wraprec TSRMLS_DC) {
       return;
     }
   }
+  /*
+   * PHP has a feature to disable certain functions and classes with
+   * disable_functions and disable_classes INI directives. This is often used
+   * as a security measure to disable potentially unsafe functions.
+   *
+   * This functionality still exists in PHP 8, but the disabled functions
+   * behave as if they are not declared at all.
+   * Prior to PHP 8, attempting to use a disabled function resulted in a
+   * warning.
+   * In PHP 8 and later, attempting to use a disabled function will throw a
+   * standard error for an undeclared function as it is indistinguishable
+   * from a function that does not exist.
+   */
 
   /*
    * If the internal function is disabled, don't wrap it; doing so breaks
    * function_exists(), and it can't be invoked anyway.
    */
+#ifndef PHP8
   if (zif_display_disabled_function
       == ((zend_internal_function*)orig_func)->handler) {
     nrl_verbosedebug(
@@ -244,6 +258,7 @@ void nr_php_wrap_internal_function(nrinternalfn_t* wraprec TSRMLS_DC) {
         NRP_PHP(wraprec->full_name));
     return;
   }
+#endif /* not PHP8 */
 
   if (wraprec->outer_wrapper_global) {
     /*
@@ -1431,9 +1446,8 @@ NR_INNER_WRAPPER(redis_connect) {
       == zend_parse_parameters_ex(
           ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC, "s|lzzz", &host,
           &host_len, &port, &ignore1, &ignore2, &ignore3)) {
-    instance = nr_php_redis_save_datastore_instance(
-        NR_PHP_INTERNAL_FN_THIS(), host,
-        port TSRMLS_CC);
+    instance = nr_php_redis_save_datastore_instance(NR_PHP_INTERNAL_FN_THIS(),
+                                                    host, port TSRMLS_CC);
   }
 
   nr_php_instrument_datastore_operation_call(nr_wrapper, NR_DATASTORE_REDIS,
@@ -2773,7 +2787,7 @@ static inline int nr_php_should_instrument_exception_handler(
 NR_INNER_WRAPPER(exception_common) {
   zval* exception_handler = NULL;
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   exception_handler = &EG(user_exception_handler);
 #else
   exception_handler = EG(user_exception_handler);
@@ -2795,7 +2809,7 @@ NR_INNER_WRAPPER(exception_common) {
    */
   nr_wrapper->oldhandler(INTERNAL_FUNCTION_PARAM_PASSTHRU);
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   exception_handler = &EG(user_exception_handler);
 #else
   exception_handler = EG(user_exception_handler);
@@ -2809,11 +2823,11 @@ NR_INNER_WRAPPER(exception_common) {
 
     func = nr_php_zval_to_function(exception_handler TSRMLS_CC);
     nr_php_add_exception_function(func TSRMLS_CC);
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   } else if (IS_UNDEF == Z_TYPE_P(exception_handler)) {
 #else
   } else if (NULL == exception_handler) {
-#endif /* PHP7 */
+#endif /* PHP7+ */
     nr_php_error_install_exception_handler(TSRMLS_C);
   }
 }
@@ -3067,13 +3081,13 @@ void nr_php_generate_internal_wrap_records(void) {
   NR_INTERNAL_WRAPREC("mysqli_stmt_init", mysqli_stmt_init, mysqli_stmt_init, 0,
                       0)
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   NR_INTERNAL_WRAPREC("mysqli::__construct", mysqliC_construct,
                       mysqli_construct, 0, 0)
 #else
   NR_INTERNAL_WRAPREC("mysqli::mysqli", mysqliC_construct, mysqli_construct, 0,
                       0)
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
   NR_INTERNAL_WRAPREC("mysqli::multi_query", mysqliC_multi_query,
                       mysqli_general_query, 0, 0)
diff --git a/agent/php_minit.c b/agent/php_minit.c
index 7d9db57d2..eb80997b4 100644
--- a/agent/php_minit.c
+++ b/agent/php_minit.c
@@ -356,7 +356,11 @@ PHP_MINIT_FUNCTION(newrelic) {
   int daemon_connect_succeeded;
   nr_conn_params_t* conn_params;
 
+#if ZEND_MODULE_API_NO < ZEND_8_0_X_API_NO /* < PHP8 */
   zend_extension dummy;
+#else
+  char dummy[] = "newrelic";
+#endif
 
   (void)type;
 
@@ -610,8 +614,11 @@ PHP_MINIT_FUNCTION(newrelic) {
   nr_php_set_opcode_handlers();
 
   nrl_debug(NRL_INIT, "MINIT processing done");
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO /* PHP 7.4+ */
+  NR_PHP_PROCESS_GLOBALS(zend_offset) = zend_get_resource_handle(dummy);
+#else
   NR_PHP_PROCESS_GLOBALS(zend_offset) = zend_get_resource_handle(&dummy);
-
+#endif
   return (SUCCESS);
 }
 
diff --git a/agent/php_newrelic.c b/agent/php_newrelic.c
index 233ab914d..8a55abe0f 100644
--- a/agent/php_newrelic.c
+++ b/agent/php_newrelic.c
@@ -114,6 +114,12 @@ void nr_print_globals(FILE* fp) {
 /*
  * New Relic API function argument descriptors.
  */
+
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO /* PHP 8.0+ */
+ZEND_BEGIN_ARG_INFO_EX(newrelic_arginfo_void, 0, 0, 0)
+ZEND_END_ARG_INFO()
+#endif /* PHP 8.0+ */
+
 ZEND_BEGIN_ARG_INFO_EX(newrelic_add_custom_parameter_arginfo, 0, 0, 2)
 ZEND_ARG_INFO(0, parameter)
 ZEND_ARG_INFO(0, value)
@@ -263,13 +269,9 @@ static zend_function_entry newrelic_functions[] = {
     /*
      * API Functions
      */
-    PHP_FE(newrelic_ignore_transaction, 0)
-    PHP_FE(newrelic_ignore_apdex, 0)
-    PHP_FE(newrelic_end_of_transaction,0)
     PHP_FE(newrelic_end_transaction,newrelic_end_transaction_arginfo)
     PHP_FE(newrelic_start_transaction,newrelic_start_transaction_arginfo)
     PHP_FE(newrelic_background_job, newrelic_background_job_arginfo)
-    PHP_FE(newrelic_notice_error,0)
     PHP_FE(newrelic_add_custom_parameter,newrelic_add_custom_parameter_arginfo)
     PHP_FE(newrelic_name_transaction, newrelic_name_transaction_arginfo)
     PHP_FE(newrelic_add_custom_tracer,newrelic_add_custom_tracer_arginfo)
@@ -278,16 +280,31 @@ static zend_function_entry newrelic_functions[] = {
     PHP_FE(newrelic_enable_params,newrelic_enable_params_arginfo)
     PHP_FE(newrelic_get_browser_timing_header,newrelic_browser_timing_arginfo)
     PHP_FE(newrelic_get_browser_timing_footer,newrelic_browser_timing_arginfo)
-    PHP_FE(newrelic_disable_autorum, 0)
     PHP_FE(newrelic_set_appname, newrelic_set_appname_arginfo)
     PHP_FE(newrelic_set_user_attributes, newrelic_set_user_attributes_arginfo)
     PHP_FE(newrelic_record_custom_event, newrelic_record_custom_event_arginfo)
     PHP_FE(newrelic_record_datastore_segment, newrelic_record_datastore_segment_arginfo)
     PHP_FE(newrelic_create_distributed_trace_payload, newrelic_create_distributed_trace_payload_arginfo)
     PHP_FE(newrelic_insert_distributed_trace_headers, newrelic_insert_distributed_trace_headers_arginfo)
-    PHP_FE(newrelic_is_sampled, 0)
     PHP_FE(newrelic_add_custom_span_parameter, newrelic_add_custom_span_parameter_arginfo)
 
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO /* PHP 8.0+ */
+    PHP_FE(newrelic_ignore_transaction, newrelic_arginfo_void)
+    PHP_FE(newrelic_ignore_apdex, newrelic_arginfo_void)
+    PHP_FE(newrelic_end_of_transaction, newrelic_arginfo_void)
+    PHP_FE(newrelic_notice_error, newrelic_arginfo_void)
+    PHP_FE(newrelic_disable_autorum, newrelic_arginfo_void)
+    PHP_FE(newrelic_is_sampled, newrelic_arginfo_void)
+#else
+    PHP_FE(newrelic_ignore_transaction, 0)
+    PHP_FE(newrelic_ignore_apdex, 0)
+    PHP_FE(newrelic_end_of_transaction,0)
+    PHP_FE(newrelic_notice_error,0)
+    PHP_FE(newrelic_disable_autorum, 0)
+    PHP_FE(newrelic_is_sampled, 0)
+#endif /* PHP8+ */
+
+
     /*
     * Other Functions
     */
@@ -295,23 +312,38 @@ static zend_function_entry newrelic_functions[] = {
     PHP_FE(newrelic_add_headers_to_context, newrelic_add_headers_to_context_arginfo)
     PHP_FE(newrelic_remove_headers_from_context, newrelic_remove_headers_from_context_arginfo)
     PHP_FE(newrelic_exception_handler, newrelic_exception_handler_arginfo)
-    PHP_FE(newrelic_get_request_metadata, 0)
     PHP_FE(newrelic_accept_distributed_trace_headers, newrelic_accept_distributed_trace_headers_arginfo)
     PHP_FE(newrelic_accept_distributed_trace_payload, newrelic_accept_distributed_trace_payload_arginfo)
     PHP_FE(newrelic_accept_distributed_trace_payload_httpsafe, newrelic_accept_distributed_trace_payload_httpsafe_arginfo)
+
+#ifdef PHP8
+    PHP_FE(newrelic_get_request_metadata, newrelic_arginfo_void)
+    PHP_FE(newrelic_get_linking_metadata, newrelic_arginfo_void)
+    PHP_FE(newrelic_get_trace_metadata, newrelic_arginfo_void)
+#else
+    PHP_FE(newrelic_get_request_metadata, 0)
     PHP_FE(newrelic_get_linking_metadata, 0)
     PHP_FE(newrelic_get_trace_metadata, 0)
+#endif /* PHP 8 */
     /*
      * Integration test helpers
      */
 #ifdef ENABLE_TESTING_API
 
-    PHP_FE(newrelic_get_hostname, 0)
     PHP_FE(newrelic_get_metric_table, newrelic_get_metric_table_arginfo)
+    PHP_FE(newrelic_is_localhost, newrelic_is_localhost_arginfo)
+
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO /* PHP 8.0+ */
+    PHP_FE(newrelic_get_hostname, newrelic_arginfo_void)
+    PHP_FE(newrelic_get_slowsqls, newrelic_arginfo_void)
+    PHP_FE(newrelic_get_trace_json, newrelic_arginfo_void)
+    PHP_FE(newrelic_is_recording, newrelic_arginfo_void)
+#else
+    PHP_FE(newrelic_get_hostname, 0)
     PHP_FE(newrelic_get_slowsqls, 0)
     PHP_FE(newrelic_get_trace_json, 0)
-    PHP_FE(newrelic_is_localhost, newrelic_is_localhost_arginfo)
     PHP_FE(newrelic_is_recording, 0)
+#endif /* PHP 8 */
 
 #endif /* ENABLE_TESTING_API */
 
diff --git a/agent/php_newrelic.h b/agent/php_newrelic.h
index 782330e1e..66f9157f2 100644
--- a/agent/php_newrelic.h
+++ b/agent/php_newrelic.h
@@ -39,7 +39,7 @@ extern zend_module_entry newrelic_module_entry;
  * majority of those changes so the rest of the code can simply use the macros
  * and not have to take the different APIs into account.
  */
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
 #define NR_SPECIALFNPTR_PROTO                              \
   struct _nruserfn_t *wraprec, nr_segment_t *auto_segment, \
       zend_execute_data *execute_data
@@ -74,7 +74,7 @@ extern zend_module_entry newrelic_module_entry;
 #define NR_ZEND_EXECUTE_HOOK zend_execute
 #endif
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
 #define NR_UNUSED_EXECUTE_DATA (void)execute_data;
 #define NR_UNUSED_HT
 #define NR_UNUSED_RETURN_VALUE (void)return_value;
@@ -88,12 +88,12 @@ extern zend_module_entry newrelic_module_entry;
 #define NR_UNUSED_RETURN_VALUE_PTR (void)return_value_ptr;
 #define NR_UNUSED_RETURN_VALUE_USED (void)return_value_used;
 #define NR_UNUSED_THIS_PTR (void)this_ptr;
-#endif /* PHP7 */
+#endif /* PHP7+ */
 
 /*
  * Convenience macro to handle unused TSRM parameters.
  */
-#if ZTS && !defined(PHP7)
+#if ZTS && !defined(PHP7) && !defined(PHP8)
 #define NR_UNUSED_TSRMLS (void)tsrm_ls;
 #else
 #define NR_UNUSED_TSRMLS
@@ -181,12 +181,19 @@ typedef void (*nrphpfn_t)(INTERNAL_FUNCTION_PARAMETERS);
 typedef void(ZEND_FASTCALL* nrphpfn_t)(INTERNAL_FUNCTION_PARAMETERS);
 #endif /* PHP < 7.3 */
 
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO
 typedef void (*nrphperrfn_t)(int type,
-                             const char* filenm,
-                             uint lineno,
+                             const char* error_filename,
+                             uint error_lineno,
+                             zend_string* message);
+#else
+typedef void (*nrphperrfn_t)(int type,
+                             const char* error_filename,
+                             uint error_lineno,
                              const char* fmt,
                              va_list args)
     ZEND_ATTRIBUTE_PTR_FORMAT(printf, 4, 0);
+#endif /* PHP >= 8.0 */
 typedef zend_op_array* (*nrphpcfile_t)(zend_file_handle* file_handle,
                                        int type TSRMLS_DC);
 typedef zend_op_array* (*nrphpcstr_t)(zval* source_string,
@@ -198,7 +205,7 @@ typedef int (*nrphphdrfn_t)(sapi_header_struct* sapi_header,
                             sapi_header_op_enum op,
                             sapi_headers_struct* sapi_headers TSRMLS_DC);
 
-#if defined(PHP7)
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
 typedef void (*nr_php_execute_internal_function_t)(
     zend_execute_data* execute_data,
     zval* return_value);
diff --git a/agent/php_vm.c b/agent/php_vm.c
index a9e58c326..2a7f8eee4 100644
--- a/agent/php_vm.c
+++ b/agent/php_vm.c
@@ -8,7 +8,7 @@
 #include "php_call.h"
 #include "util_logging.h"
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
 
 /*
  * An entry in the previous_opcode_handlers table.
@@ -134,8 +134,8 @@ static int nr_php_handle_cufa_fcall(zend_execute_data* execute_data) {
 
   /*
    * To actually determine whether this is a call_user_func_array() call we
-   * have to look at the previous opcode. ZEND_DO_FCALL will never be the first
-   * opcode in an op array -- minimally, there is always at least a
+   * have to look at one of the previous opcodes. ZEND_DO_FCALL will never be
+   * the first opcode in an op array -- minimally, there is always at least a
    * ZEND_INIT_FCALL before it -- so this is safe.
    *
    * When PHP 7 flattens a call_user_func_array() call into direct opcodes, it
@@ -146,15 +146,23 @@ static int nr_php_handle_cufa_fcall(zend_execute_data* execute_data) {
    * https://github.com/php/php-src/blob/php-7.0.19/Zend/zend_compile.c#L3082-L3098
    * https://github.com/php/php-src/blob/php-7.1.5/Zend/zend_compile.c#L3564-L3580
    *
+   * In PHP 8, a ZEND_CHECK_UNDEF_ARGS opcode is added after the call to
+   * ZEND_SEND_ARRAY and before ZEND_DO_FCALL so we need to look back two opcodes
+   * instead of just one.
+   *
    * Note that this heuristic will fail if the Zend Engine ever starts
-   * compiling flattened call_user_func_array() calls differently. (There is a
-   * change coming in PHP 7.2, but it only optimizes array_slice() calls, which
-   * as an internal function won't get this far anyway.) We can disable this
-   * behaviour by setting the ZEND_COMPILE_NO_BUILTINS compiler flag, but since
-   * that will cause additional performance overhead, this should be considered
-   * a last resort.
+   * compiling flattened call_user_func_array() calls differently. PHP 7.2 made a
+   * change, but it only optimized array_slice() calls, which as an internal
+   * function won't get this far anyway.) We can disable this behaviour by setting
+   * the ZEND_COMPILE_NO_BUILTINS compiler flag, but since that will cause
+   * additional performance overhead, this should be considered a last resort.
    */
+#ifdef PHP8
+  prev_opline = execute_data->opline - 2;
+#else
   prev_opline = execute_data->opline - 1;
+#endif
+
   if (ZEND_SEND_ARRAY == prev_opline->opcode) {
     if (UNEXPECTED((NULL == execute_data->call)
                    || (NULL == execute_data->call->func))) {
@@ -216,4 +224,4 @@ void nr_php_set_opcode_handlers(void) {}
 
 void nr_php_remove_opcode_handlers(void) {}
 
-#endif /* PHP7 */
+#endif /* PHP 7.0+ */
diff --git a/agent/php_zval.h b/agent/php_zval.h
index 54159cd41..5991c1198 100644
--- a/agent/php_zval.h
+++ b/agent/php_zval.h
@@ -58,9 +58,9 @@
  *           nr_php_zval_free() rather than nr_php_zval_dtor().
  */
 inline static zval* nr_php_zval_alloc(void) {
-  zval* zv;
+  zval* zv = NULL;
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   zv = (zval*)emalloc(sizeof(zval));
   ZVAL_UNDEF(zv);
 #else
@@ -343,7 +343,7 @@ static inline void nr_php_zval_bool(zval* zv, int b) {
  *           that function will then set the value).
  */
 static inline void nr_php_zval_prepare_out_arg(zval* zv) {
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   ZVAL_NEW_REF(zv, &EG(uninitialized_zval));
 #else
   ZVAL_NULL(zv);
@@ -363,7 +363,7 @@ static inline void nr_php_zval_prepare_out_arg(zval* zv) {
  * Note that you will need to use nr_php_zval_real_value() (below) if you don't
  * want to do this in place.
  */
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
 #define nr_php_zval_unwrap(zv) ZVAL_DEREF(zv)
 
 /*
diff --git a/agent/tests/test_api_internal.c b/agent/tests/test_api_internal.c
index b8b0143bb..e859bbf19 100644
--- a/agent/tests/test_api_internal.c
+++ b/agent/tests/test_api_internal.c
@@ -55,11 +55,26 @@ static void test_invalid_parameters(TSRMLS_D) {
   tlib_php_request_start();
 
   /* Literally any parameter should cause this to bail. */
+#ifdef PHP8
+  tlib_php_request_eval("$exception = false;"
+                        "try {"
+                        "    $value = newrelic_get_trace_json('invalid');"
+                        "    echo \"No exception, returned \" . $value . \".\\n\";"
+                        "} catch(ArgumentCountError $_e) {"
+                        "    $exception = true;"
+                        "}" TSRMLS_CC);
+  retval = tlib_php_request_eval_expr("$exception;" TSRMLS_CC);
+
+  tlib_pass_if_zval_is_bool_true(
+      "newrelic_get_trace_json() throws an exception when a parameter is given",
+      retval);
+#else
   retval = nr_php_call(NULL, "newrelic_get_trace_json", param);
 
   tlib_pass_if_zval_is_bool_false(
       "newrelic_get_trace_json() returns false when a parameter is given",
       retval);
+#endif
 
   nr_php_zval_free(&param);
   nr_php_zval_free(&retval);
diff --git a/agent/tests/test_zval.c b/agent/tests/test_zval.c
index 5905a265c..630cdd258 100644
--- a/agent/tests/test_zval.c
+++ b/agent/tests/test_zval.c
@@ -93,13 +93,18 @@ static void test_is_zval_valid_callable(TSRMLS_D) {
   test_valid_callable("'date'" TSRMLS_CC);
   test_valid_callable(
       "array(new ReflectionFunction('date'), 'isDisabled')" TSRMLS_CC);
+#ifdef PHP8
+  test_valid_callable("array('ReflectionReference', 'fromArrayElement')" TSRMLS_CC);
+  test_valid_callable("'ReflectionReference::fromArrayElement'" TSRMLS_CC);
+#else
   test_valid_callable("array('ReflectionFunction', 'export')" TSRMLS_CC);
   test_valid_callable("'ReflectionFunction::export'" TSRMLS_CC);
+#endif
   test_valid_callable("function () {}" TSRMLS_CC);
 
-#ifdef PHP7
+#if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO /* PHP 7.0+ */
   test_valid_callable("new class { function __invoke() {} }" TSRMLS_CC);
-#endif /* PHP7 */
+#endif /* PHP 7.0+ */
 
   tlib_php_request_end();
 }
diff --git a/agent/tests/tlib_php.c b/agent/tests/tlib_php.c
index 853f2145c..daadf32da 100644
--- a/agent/tests/tlib_php.c
+++ b/agent/tests/tlib_php.c
@@ -125,7 +125,12 @@ static const char* tlib_php_new_interned_string(const char* key,
 }
 #endif
 
-#if ZEND_MODULE_API_NO >= ZEND_7_3_X_API_NO
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO
+static zend_string* ZEND_FASTCALL
+tlib_php_init_interned_string(const char* str, size_t size, bool permanent) {
+  return zend_string_init(str, size, permanent);
+}
+#elif ZEND_MODULE_API_NO >= ZEND_7_3_X_API_NO
 static zend_string* ZEND_FASTCALL tlib_php_init_interned_string(const char* str,
                                                                 size_t size,
                                                                 int permanent) {
@@ -429,7 +434,14 @@ zval* tlib_php_request_eval_expr(const char* code TSRMLS_DC) {
   return rv;
 }
 
-#if ZEND_MODULE_API_NO >= ZEND_7_3_X_API_NO
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO
+static void tlib_php_error_silence_cb(int type NRUNUSED,
+                                      const char* error_filename NRUNUSED,
+                                      const uint32_t error_lineno NRUNUSED,
+                                      zend_string* message NRUNUSED) {
+  /* Squash the error by doing absolutely nothing. */
+}
+#elif ZEND_MODULE_API_NO >= ZEND_7_3_X_API_NO
 static void tlib_php_error_silence_cb(int type NRUNUSED,
                                       const char* error_filename NRUNUSED,
                                       const uint32_t error_lineno NRUNUSED,
@@ -442,7 +454,9 @@ static void tlib_php_error_silence_cb(int type NRUNUSED,
 int tlib_php_require_extension(const char* extension TSRMLS_DC) {
   char* file = NULL;
   int loaded = 0;
-#if ZEND_MODULE_API_NO >= ZEND_7_3_X_API_NO
+#if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO
+  void (*prev_error_cb)(int, const char*, const uint32_t, zend_string*);
+#elif ZEND_MODULE_API_NO >= ZEND_7_3_X_API_NO
   void (*prev_error_cb)(int, const char*, const uint32_t, const char*, va_list);
 #else
   zend_error_handling_t prev_error;