diff --git a/lib/api/model/initial_snapshot.dart b/lib/api/model/initial_snapshot.dart
index 1adc44196f..5882122baa 100644
--- a/lib/api/model/initial_snapshot.dart
+++ b/lib/api/model/initial_snapshot.dart
@@ -85,6 +85,8 @@ class InitialSnapshot {
 
   final Uri? serverEmojiDataUrl; // TODO(server-6)
 
+  final String? realmEmptyTopicDisplayName; // TODO(server-10)
+
   @JsonKey(readValue: _readUsersIsActiveFallbackTrue)
   final List<User> realmUsers;
   @JsonKey(readValue: _readUsersIsActiveFallbackFalse)
@@ -138,6 +140,7 @@ class InitialSnapshot {
     required this.realmDefaultExternalAccounts,
     required this.maxFileUploadSizeMib,
     required this.serverEmojiDataUrl,
+    required this.realmEmptyTopicDisplayName,
     required this.realmUsers,
     required this.realmNonActiveUsers,
     required this.crossRealmBots,
diff --git a/lib/api/model/initial_snapshot.g.dart b/lib/api/model/initial_snapshot.g.dart
index 7ff9755812..79cfbe5557 100644
--- a/lib/api/model/initial_snapshot.g.dart
+++ b/lib/api/model/initial_snapshot.g.dart
@@ -85,6 +85,7 @@ InitialSnapshot _$InitialSnapshotFromJson(
       json['server_emoji_data_url'] == null
           ? null
           : Uri.parse(json['server_emoji_data_url'] as String),
+  realmEmptyTopicDisplayName: json['realm_empty_topic_display_name'] as String?,
   realmUsers:
       (InitialSnapshot._readUsersIsActiveFallbackTrue(json, 'realm_users')
               as List<dynamic>)
@@ -135,6 +136,7 @@ Map<String, dynamic> _$InitialSnapshotToJson(InitialSnapshot instance) =>
       'realm_default_external_accounts': instance.realmDefaultExternalAccounts,
       'max_file_upload_size_mib': instance.maxFileUploadSizeMib,
       'server_emoji_data_url': instance.serverEmojiDataUrl?.toString(),
+      'realm_empty_topic_display_name': instance.realmEmptyTopicDisplayName,
       'realm_users': instance.realmUsers,
       'realm_non_active_users': instance.realmNonActiveUsers,
       'cross_realm_bots': instance.crossRealmBots,
diff --git a/lib/model/autocomplete.dart b/lib/model/autocomplete.dart
index cf3b484564..073255bc9d 100644
--- a/lib/model/autocomplete.dart
+++ b/lib/model/autocomplete.dart
@@ -921,7 +921,7 @@ class TopicAutocompleteView extends AutocompleteView<TopicAutocompleteQuery, Top
   }
 
   TopicAutocompleteResult? _testTopic(TopicAutocompleteQuery query, TopicName topic) {
-    if (query.testTopic(topic)) {
+    if (query.testTopic(topic, store)) {
       return TopicAutocompleteResult(topic: topic);
     }
     return null;
@@ -939,10 +939,17 @@ class TopicAutocompleteView extends AutocompleteView<TopicAutocompleteQuery, Top
 class TopicAutocompleteQuery extends AutocompleteQuery {
   TopicAutocompleteQuery(super.raw);
 
-  bool testTopic(TopicName topic) {
+  bool testTopic(TopicName topic, PerAccountStore store) {
     // TODO(#881): Sort by match relevance, like web does.
+
+    // ignore: unnecessary_null_comparison // null topic names soon to be enabled
+    if (topic.displayName == null) {
+      return store.realmEmptyTopicDisplayName.toLowerCase()
+        .contains(raw.toLowerCase());
+    }
     return topic.displayName != raw
-      && topic.displayName.toLowerCase().contains(raw.toLowerCase());
+      // ignore: unnecessary_non_null_assertion // null topic names soon to be enabled
+      && topic.displayName!.toLowerCase().contains(raw.toLowerCase());
   }
 
   @override
diff --git a/lib/model/store.dart b/lib/model/store.dart
index 5d7fcda117..8f00aed2bc 100644
--- a/lib/model/store.dart
+++ b/lib/model/store.dart
@@ -302,6 +302,7 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, UserStore, Channel
       realmMandatoryTopics: initialSnapshot.realmMandatoryTopics,
       realmWaitingPeriodThreshold: initialSnapshot.realmWaitingPeriodThreshold,
       maxFileUploadSizeMib: initialSnapshot.maxFileUploadSizeMib,
+      realmEmptyTopicDisplayName: initialSnapshot.realmEmptyTopicDisplayName,
       realmDefaultExternalAccounts: initialSnapshot.realmDefaultExternalAccounts,
       customProfileFields: _sortCustomProfileFields(initialSnapshot.customProfileFields),
       emailAddressVisibility: initialSnapshot.emailAddressVisibility,
@@ -344,6 +345,7 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, UserStore, Channel
     required this.realmMandatoryTopics,
     required this.realmWaitingPeriodThreshold,
     required this.maxFileUploadSizeMib,
+    required String? realmEmptyTopicDisplayName,
     required this.realmDefaultExternalAccounts,
     required this.customProfileFields,
     required this.emailAddressVisibility,
@@ -362,6 +364,7 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, UserStore, Channel
        assert(realmUrl == connection.realmUrl),
        assert(emoji.realmUrl == realmUrl),
        _globalStore = globalStore,
+       _realmEmptyTopicDisplayName = realmEmptyTopicDisplayName,
        _emoji = emoji,
        _users = users,
        _channels = channels,
@@ -414,6 +417,18 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, UserStore, Channel
   /// For docs, please see [InitialSnapshot.realmWaitingPeriodThreshold].
   final int realmWaitingPeriodThreshold;  // TODO(#668): update this realm setting
   final int maxFileUploadSizeMib; // No event for this.
+
+  /// The display name to use for empty topics.
+  ///
+  /// This should only be accessed when FL >= 334, since topics cannot
+  /// be empty otherwise.
+  // TODO(server-10) simplify this
+  String get realmEmptyTopicDisplayName {
+    assert(_realmEmptyTopicDisplayName != null); // TODO(log)
+    return _realmEmptyTopicDisplayName ?? 'general chat';
+  }
+  final String? _realmEmptyTopicDisplayName; // TODO(#668): update this realm setting
+
   final Map<String, RealmDefaultExternalAccount> realmDefaultExternalAccounts;
   List<CustomProfileField> customProfileFields;
   /// For docs, please see [InitialSnapshot.emailAddressVisibility].
diff --git a/lib/widgets/autocomplete.dart b/lib/widgets/autocomplete.dart
index e34946a31f..a31369c3d9 100644
--- a/lib/widgets/autocomplete.dart
+++ b/lib/widgets/autocomplete.dart
@@ -415,12 +415,23 @@ class TopicAutocomplete extends AutocompleteField<TopicAutocompleteQuery, TopicA
 
   @override
   Widget buildItem(BuildContext context, int index, TopicAutocompleteResult option) {
+    final Widget child;
+    // ignore: unnecessary_null_comparison // null topic names soon to be enabled
+    if (option.topic.displayName == null) {
+      final store = PerAccountStoreWidget.of(context);
+      child = Text(store.realmEmptyTopicDisplayName,
+        style: const TextStyle(fontStyle: FontStyle.italic));
+    } else {
+      // ignore: unnecessary_non_null_assertion // null topic names soon to be enabled
+      child = Text(option.topic.displayName!);
+    }
+
     return InkWell(
       onTap: () {
         _onTapOption(context, option);
       },
       child: Padding(
         padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
-        child: Text(option.topic.displayName)));
+        child: child));
   }
 }
diff --git a/lib/widgets/compose_box.dart b/lib/widgets/compose_box.dart
index 902d57892d..7f47046d11 100644
--- a/lib/widgets/compose_box.dart
+++ b/lib/widgets/compose_box.dart
@@ -182,7 +182,8 @@ class ComposeTopicController extends ComposeController<TopicValidationError> {
   }
 
   void setTopic(TopicName newTopic) {
-    value = TextEditingValue(text: newTopic.displayName);
+    // ignore: dead_null_aware_expression // null topic names soon to be enabled
+    value = TextEditingValue(text: newTopic.displayName ?? '');
   }
 }
 
diff --git a/lib/widgets/inbox.dart b/lib/widgets/inbox.dart
index 480437c912..81133cde20 100644
--- a/lib/widgets/inbox.dart
+++ b/lib/widgets/inbox.dart
@@ -532,12 +532,15 @@ class _TopicItem extends StatelessWidget {
                 style: TextStyle(
                   fontSize: 17,
                   height: (20 / 17),
+                  // ignore: unnecessary_null_comparison // null topic names soon to be enabled
+                  fontStyle: topic.displayName == null ? FontStyle.italic : null,
                   // TODO(design) check if this is the right variable
                   color: designVariables.labelMenuButton,
                 ),
                 maxLines: 2,
                 overflow: TextOverflow.ellipsis,
-                topic.displayName))),
+                // ignore: dead_null_aware_expression // null topic names soon to be enabled
+                topic.displayName ?? store.realmEmptyTopicDisplayName))),
             const SizedBox(width: 12),
             if (hasMention) const _IconMarker(icon: ZulipIcons.at_sign),
             // TODO(design) copies the "@" marker color; is there a better color?
diff --git a/lib/widgets/message_list.dart b/lib/widgets/message_list.dart
index 2cc9e2963e..b8557162e9 100644
--- a/lib/widgets/message_list.dart
+++ b/lib/widgets/message_list.dart
@@ -339,8 +339,11 @@ class MessageListAppBarTitle extends StatelessWidget {
     return Row(
       mainAxisSize: MainAxisSize.min,
       children: [
-        Flexible(child: Text(topic.displayName, style: const TextStyle(
+        // ignore: dead_null_aware_expression // null topic names soon to be enabled
+        Flexible(child: Text(topic.displayName ?? store.realmEmptyTopicDisplayName, style: TextStyle(
           fontSize: 13,
+          // ignore: unnecessary_null_comparison // null topic names soon to be enabled
+          fontStyle: topic.displayName == null ? FontStyle.italic : null,
         ).merge(weightVariableTextStyle(context)))),
         if (icon != null)
           Padding(
@@ -1092,11 +1095,15 @@ class StreamMessageRecipientHeader extends StatelessWidget {
       child: Row(
         children: [
           Flexible(
-            child: Text(topic.displayName,
+            // ignore: dead_null_aware_expression // null topic names soon to be enabled
+            child: Text(topic.displayName ?? store.realmEmptyTopicDisplayName,
               // TODO: Give a way to see the whole topic (maybe a
               //   long-press interaction?)
               overflow: TextOverflow.ellipsis,
-              style: recipientHeaderTextStyle(context))),
+              style: recipientHeaderTextStyle(context,
+                // ignore: unnecessary_null_comparison // null topic names soon to be enabled
+                fontStyle: topic.displayName == null ? FontStyle.italic : null,
+              ))),
           const SizedBox(width: 4),
           Icon(size: 14, color: designVariables.title.withFadedAlpha(0.5),
             // A null [Icon.icon] makes a blank space.
@@ -1191,12 +1198,13 @@ class DmRecipientHeader extends StatelessWidget {
   }
 }
 
-TextStyle recipientHeaderTextStyle(BuildContext context) {
+TextStyle recipientHeaderTextStyle(BuildContext context, {FontStyle? fontStyle}) {
   return TextStyle(
     color: DesignVariables.of(context).title,
     fontSize: 16,
     letterSpacing: proportionalLetterSpacing(context, 0.02, baseFontSize: 16),
     height: (18 / 16),
+    fontStyle: fontStyle,
   ).merge(weightVariableTextStyle(context, wght: 600));
 }
 
diff --git a/test/example_data.dart b/test/example_data.dart
index 04d6723b7a..635667eb6c 100644
--- a/test/example_data.dart
+++ b/test/example_data.dart
@@ -881,6 +881,8 @@ TestGlobalStore globalStore({List<Account> accounts = const []}) {
 }
 const _globalStore = globalStore;
 
+const String defaultRealmEmptyTopicDisplayName = 'test general chat';
+
 InitialSnapshot initialSnapshot({
   String? queueId,
   int? lastEventId,
@@ -906,6 +908,7 @@ InitialSnapshot initialSnapshot({
   Map<String, RealmDefaultExternalAccount>? realmDefaultExternalAccounts,
   int? maxFileUploadSizeMib,
   Uri? serverEmojiDataUrl,
+  String? realmEmptyTopicDisplayName,
   List<User>? realmUsers,
   List<User>? realmNonActiveUsers,
   List<User>? crossRealmBots,
@@ -943,6 +946,7 @@ InitialSnapshot initialSnapshot({
     maxFileUploadSizeMib: maxFileUploadSizeMib ?? 25,
     serverEmojiDataUrl: serverEmojiDataUrl
       ?? realmUrl.replace(path: '/static/emoji.json'),
+    realmEmptyTopicDisplayName: realmEmptyTopicDisplayName ?? defaultRealmEmptyTopicDisplayName,
     realmUsers: realmUsers ?? [],
     realmNonActiveUsers: realmNonActiveUsers ?? [],
     crossRealmBots: crossRealmBots ?? [],
diff --git a/test/model/autocomplete_test.dart b/test/model/autocomplete_test.dart
index e916151426..16b92d98d4 100644
--- a/test/model/autocomplete_test.dart
+++ b/test/model/autocomplete_test.dart
@@ -1027,8 +1027,9 @@ void main() {
   });
 
   group('TopicAutocompleteQuery.testTopic', () {
+    final store = eg.store();
     void doCheck(String rawQuery, String topic, bool expected) {
-      final result = TopicAutocompleteQuery(rawQuery).testTopic(eg.t(topic));
+      final result = TopicAutocompleteQuery(rawQuery).testTopic(eg.t(topic), store);
       expected ? check(result).isTrue() : check(result).isFalse();
     }
 
diff --git a/test/widgets/autocomplete_test.dart b/test/widgets/autocomplete_test.dart
index 2e0ad50156..484c3b2454 100644
--- a/test/widgets/autocomplete_test.dart
+++ b/test/widgets/autocomplete_test.dart
@@ -99,9 +99,11 @@ Future<Finder> setupToComposeInput(WidgetTester tester, {
 /// Returns a [Finder] for the topic input's [TextField].
 Future<Finder> setupToTopicInput(WidgetTester tester, {
   required List<GetStreamTopicsEntry> topics,
+  String? realmEmptyTopicDisplayName,
 }) async {
   addTearDown(testBinding.reset);
-  await testBinding.globalStore.add(eg.selfAccount, eg.initialSnapshot());
+  await testBinding.globalStore.add(eg.selfAccount, eg.initialSnapshot(
+    realmEmptyTopicDisplayName: realmEmptyTopicDisplayName));
   final store = await testBinding.globalStore.perAccount(eg.selfAccount.id);
   await store.addUser(eg.selfUser);
   final connection = store.connection as FakeApiConnection;
@@ -392,16 +394,11 @@ void main() {
   });
 
   group('TopicAutocomplete', () {
-    void checkTopicShown(GetStreamTopicsEntry topic, PerAccountStore store, {required bool expected}) {
-      check(find.text(topic.name.displayName).evaluate().length).equals(expected ? 1 : 0);
-    }
-
     testWidgets('options appear, disappear, and change correctly', (WidgetTester tester) async {
       final topic1 = eg.getStreamTopicsEntry(maxId: 1, name: 'Topic one');
       final topic2 = eg.getStreamTopicsEntry(maxId: 2, name: 'Topic two');
       final topic3 = eg.getStreamTopicsEntry(maxId: 3, name: 'Topic three');
       final topicInputFinder = await setupToTopicInput(tester, topics: [topic1, topic2, topic3]);
-      final store = await testBinding.globalStore.perAccount(eg.selfAccount.id);
 
       // Options are filtered correctly for query
       // TODO(#226): Remove this extra edit when this bug is fixed.
@@ -410,24 +407,24 @@ void main() {
       await tester.pumpAndSettle();
 
       // "topic three" and "topic two" appear, but not "topic one"
-      checkTopicShown(topic1, store, expected: false);
-      checkTopicShown(topic2, store, expected: true);
-      checkTopicShown(topic3, store, expected: true);
+      check(find.text('Topic one'  )).findsNothing();
+      check(find.text('Topic two'  )).findsOne();
+      check(find.text('Topic three')).findsOne();
 
       // Finishing autocomplete updates topic box; causes options to disappear
       await tester.tap(find.text('Topic three'));
       await tester.pumpAndSettle();
       check(tester.widget<TextField>(topicInputFinder).controller!.text)
         .equals(topic3.name.displayName);
-      checkTopicShown(topic1, store, expected: false);
-      checkTopicShown(topic2, store, expected: false);
-      checkTopicShown(topic3, store, expected: true); // shown in `_TopicInput` once
+      check(find.text('Topic one'  )).findsNothing();
+      check(find.text('Topic two'  )).findsNothing();
+      check(find.text('Topic three')).findsOne(); // shown in `_TopicInput` once
 
       // Then a new autocomplete intent brings up options again
       await tester.enterText(topicInputFinder, 'Topic');
       await tester.enterText(topicInputFinder, 'Topic T');
       await tester.pumpAndSettle();
-      checkTopicShown(topic2, store, expected: true);
+      check(find.text('Topic two')).findsOne();
     });
 
     testWidgets('text selection is reset on choosing an option', (tester) async {
@@ -464,5 +461,47 @@ void main() {
 
       await tester.pump(Duration.zero);
     });
+
+    testWidgets('display realmEmptyTopicDisplayName for empty topic', (tester) async {
+      final topic = eg.getStreamTopicsEntry(name: '');
+      final topicInputFinder = await setupToTopicInput(tester, topics: [topic],
+        realmEmptyTopicDisplayName: 'some display name');
+
+      // TODO(#226): Remove this extra edit when this bug is fixed.
+      await tester.enterText(topicInputFinder, ' ');
+      await tester.enterText(topicInputFinder, '');
+      await tester.pumpAndSettle();
+
+      check(find.text('some display name')).findsOne();
+    }, skip: true); // null topic names soon to be enabled
+
+    testWidgets('match realmEmptyTopicDisplayName in autocomplete', (tester) async {
+      final topic = eg.getStreamTopicsEntry(name: '');
+      final topicInputFinder = await setupToTopicInput(tester, topics: [topic],
+        realmEmptyTopicDisplayName: 'general chat');
+
+      // TODO(#226): Remove this extra edit when this bug is fixed.
+      await tester.enterText(topicInputFinder, 'general ch');
+      await tester.enterText(topicInputFinder, 'general cha');
+      await tester.pumpAndSettle();
+
+      check(find.text('general chat')).findsOne();
+    }, skip: true); // null topic names soon to be enabled
+
+    testWidgets('autocomplete to realmEmptyTopicDisplayName sets topic to empty string', (tester) async {
+      final topic = eg.getStreamTopicsEntry(name: '');
+      final topicInputFinder = await setupToTopicInput(tester, topics: [topic],
+        realmEmptyTopicDisplayName: 'general chat');
+      final controller = tester.widget<TextField>(topicInputFinder).controller!;
+
+      // TODO(#226): Remove this extra edit when this bug is fixed.
+      await tester.enterText(topicInputFinder, 'general ch');
+      await tester.enterText(topicInputFinder, 'general cha');
+      await tester.pumpAndSettle();
+
+      await tester.tap(find.text('general chat'));
+      await tester.pump(Duration.zero);
+      check(controller.value).text.equals('');
+    }, skip: true); // null topic names soon to be enabled
   });
 }
diff --git a/test/widgets/inbox_test.dart b/test/widgets/inbox_test.dart
index 3fa3713d5d..7b2be9176e 100644
--- a/test/widgets/inbox_test.dart
+++ b/test/widgets/inbox_test.dart
@@ -307,6 +307,15 @@ void main() {
       });
     });
 
+    testWidgets('empty topic', (tester) async {
+      final channel = eg.stream();
+      await setupPage(tester,
+        streams: [channel],
+        subscriptions: [(eg.subscription(channel))],
+        unreadMessages: [eg.streamMessage(stream: channel, topic: '')]);
+      check(find.text(eg.defaultRealmEmptyTopicDisplayName)).findsOne();
+    }, skip: true); // null topic names soon to be enabled
+
     group('topic visibility', () {
       final channel = eg.stream();
       const topic = 'topic';
diff --git a/test/widgets/message_list_test.dart b/test/widgets/message_list_test.dart
index 7107e936ca..bd54412a46 100644
--- a/test/widgets/message_list_test.dart
+++ b/test/widgets/message_list_test.dart
@@ -194,6 +194,16 @@ void main() {
   group('app bar', () {
     // Tests for the topic action sheet are in test/widgets/action_sheet_test.dart.
 
+    testWidgets('handle empty topics', (tester) async {
+      final channel = eg.stream();
+      await setupMessageListPage(tester,
+        narrow: eg.topicNarrow(channel.streamId, ''),
+        streams: [channel],
+        messageCount: 1);
+      checkAppBarChannelTopic(
+        channel.name, eg.defaultRealmEmptyTopicDisplayName);
+    }, skip: true); // null topic names soon to be enabled
+
     testWidgets('has channel-feed action for topic narrows', (tester) async {
       final pushedRoutes = <Route<void>>[];
       final navObserver = TestNavigatorObserver()
@@ -934,6 +944,26 @@ void main() {
         check(findInMessageList('topic name')).length.equals(1);
       });
 
+      final messageEmptyTopic = eg.streamMessage(stream: stream, topic: '');
+
+      testWidgets('show general chat for empty topics with channel name', (tester) async {
+        await setupMessageListPage(tester,
+          narrow: const CombinedFeedNarrow(),
+          messages: [messageEmptyTopic], subscriptions: [eg.subscription(stream)]);
+        await tester.pump();
+        check(findInMessageList('stream name')).single;
+        check(findInMessageList(eg.defaultRealmEmptyTopicDisplayName)).single;
+      }, skip: true); // null topic names soon to be enabled
+
+      testWidgets('show general chat for empty topics without channel name', (tester) async {
+        await setupMessageListPage(tester,
+          narrow: TopicNarrow.ofMessage(messageEmptyTopic),
+          messages: [messageEmptyTopic]);
+        await tester.pump();
+        check(findInMessageList('stream name')).isEmpty();
+        check(findInMessageList(eg.defaultRealmEmptyTopicDisplayName)).single;
+      }, skip: true); // null topic names soon to be enabled
+
       testWidgets('show topic visibility icon when followed', (tester) async {
         await setupMessageListPage(tester,
           narrow: const CombinedFeedNarrow(),