diff --git a/analysis_options.yaml b/analysis_options.yaml
index 6f697717..7b5c1a64 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -11,6 +11,7 @@ analyzer:
     document_ignores: ignore
     one_member_abstracts: ignore
     cascade_invocations: ignore
+    cast_nullable_to_non_nullable: ignore
   exclude:
     - build/**
 linter:
diff --git a/lib/src/config/app_dependencies.dart b/lib/src/config/app_dependencies.dart
index de78c861..da51e5e8 100644
--- a/lib/src/config/app_dependencies.dart
+++ b/lib/src/config/app_dependencies.dart
@@ -65,7 +65,7 @@ class AppDependencies {
   late final DataRepository<Country> countryRepository;
   late final DataRepository<Language> languageRepository;
   late final DataRepository<User> userRepository;
-  late final DataRepository<UserAppSettings> userAppSettingsRepository;
+  late final DataRepository<AppSettings> appSettingsRepository;
   late final DataRepository<UserContentPreferences>
   userContentPreferencesRepository;
   late final DataRepository<PushNotificationDevice>
@@ -190,12 +190,12 @@ class AppDependencies {
         toJson: (item) => item.toJson(),
         logger: Logger('DataMongodb<User>'),
       );
-      final userAppSettingsClient = DataMongodb<UserAppSettings>(
+      final appSettingsClient = DataMongodb<AppSettings>(
         connectionManager: _mongoDbConnectionManager,
-        modelName: 'user_app_settings',
-        fromJson: UserAppSettings.fromJson,
+        modelName: 'app_settings',
+        fromJson: AppSettings.fromJson,
         toJson: (item) => item.toJson(),
-        logger: Logger('DataMongodb<UserAppSettings>'),
+        logger: Logger('DataMongodb<AppSettings>'),
       );
       final userContentPreferencesClient = DataMongodb<UserContentPreferences>(
         connectionManager: _mongoDbConnectionManager,
@@ -306,8 +306,8 @@ class AppDependencies {
       countryRepository = DataRepository(dataClient: countryClient);
       languageRepository = DataRepository(dataClient: languageClient);
       userRepository = DataRepository(dataClient: userClient);
-      userAppSettingsRepository = DataRepository(
-        dataClient: userAppSettingsClient,
+      appSettingsRepository = DataRepository(
+        dataClient: appSettingsClient,
       );
       userContentPreferencesRepository = DataRepository(
         dataClient: userContentPreferencesClient,
@@ -359,7 +359,7 @@ class AppDependencies {
         verificationCodeStorageService: verificationCodeStorageService,
         permissionService: permissionService,
         emailRepository: emailRepository,
-        userAppSettingsRepository: userAppSettingsRepository,
+        appSettingsRepository: appSettingsRepository,
         userContentPreferencesRepository: userContentPreferencesRepository,
         log: Logger('AuthService'),
       );
diff --git a/lib/src/models/models.dart b/lib/src/models/models.dart
new file mode 100644
index 00000000..97f2ceaa
--- /dev/null
+++ b/lib/src/models/models.dart
@@ -0,0 +1,2 @@
+export 'push_notification/push_notification.dart';
+export 'request_id.dart';
diff --git a/lib/src/models/push_notification/firebase_request_body.dart b/lib/src/models/push_notification/firebase_request_body.dart
new file mode 100644
index 00000000..90671411
--- /dev/null
+++ b/lib/src/models/push_notification/firebase_request_body.dart
@@ -0,0 +1,95 @@
+import 'package:core/core.dart';
+import 'package:equatable/equatable.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'firebase_request_body.g.dart';
+
+/// {@template firebase_request_body}
+/// Represents the top-level structure for a Firebase Cloud Messaging
+/// v1 API request.
+/// {@endtemplate}
+@JsonSerializable(
+  explicitToJson: true,
+  includeIfNull: true,
+  checked: true,
+  createFactory: false,
+)
+class FirebaseRequestBody extends Equatable {
+  /// {@macro firebase_request_body}
+  const FirebaseRequestBody({required this.message});
+
+  /// The message payload.
+  final FirebaseMessage message;
+
+  /// Converts this [FirebaseRequestBody] instance to a JSON map.
+  Map<String, dynamic> toJson() => _$FirebaseRequestBodyToJson(this);
+
+  @override
+  List<Object> get props => [message];
+}
+
+/// {@template firebase_message}
+/// Represents the message object within a Firebase request.
+/// {@endtemplate}
+@JsonSerializable(
+  explicitToJson: true,
+  includeIfNull: true,
+  checked: true,
+  createFactory: false,
+)
+class FirebaseMessage extends Equatable {
+  /// {@macro firebase_message}
+  const FirebaseMessage({
+    required this.token,
+    required this.notification,
+    required this.data,
+  });
+
+  /// The registration token of the device to send the message to.
+  final String token;
+
+  /// The notification content.
+  final FirebaseNotification notification;
+
+  /// The custom data payload.
+  final PushNotificationPayload data;
+
+  /// Converts this [FirebaseMessage] instance to a JSON map.
+  Map<String, dynamic> toJson() => _$FirebaseMessageToJson(this);
+
+  @override
+  List<Object> get props => [token, notification, data];
+}
+
+/// {@template firebase_notification}
+/// Represents the notification content within a Firebase message.
+/// {@endtemplate}
+@JsonSerializable(
+  explicitToJson: true,
+  includeIfNull: true,
+  checked: true,
+  createFactory: false,
+)
+class FirebaseNotification extends Equatable {
+  /// {@macro firebase_notification}
+  const FirebaseNotification({
+    required this.title,
+    this.body,
+    this.image,
+  });
+
+  /// The notification's title.
+  final String title;
+
+  /// The notification's body text.
+  final String? body;
+
+  /// The URL of an image to be displayed in the notification.
+  final String? image;
+
+  /// Converts this [FirebaseNotification] instance to a JSON map.
+  Map<String, dynamic> toJson() => _$FirebaseNotificationToJson(this);
+
+  @override
+  List<Object?> get props => [title, body, image];
+}
diff --git a/lib/src/models/push_notification/firebase_request_body.g.dart b/lib/src/models/push_notification/firebase_request_body.g.dart
new file mode 100644
index 00000000..bba3ed3d
--- /dev/null
+++ b/lib/src/models/push_notification/firebase_request_body.g.dart
@@ -0,0 +1,37 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'firebase_request_body.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+Map<String, dynamic> _$FirebaseRequestBodyToJson(
+  FirebaseRequestBody instance,
+) => <String, dynamic>{
+  'stringify': instance.stringify,
+  'hashCode': instance.hashCode,
+  'message': instance.message.toJson(),
+  'props': instance.props,
+};
+
+Map<String, dynamic> _$FirebaseMessageToJson(FirebaseMessage instance) =>
+    <String, dynamic>{
+      'stringify': instance.stringify,
+      'hashCode': instance.hashCode,
+      'token': instance.token,
+      'notification': instance.notification.toJson(),
+      'data': instance.data.toJson(),
+      'props': instance.props,
+    };
+
+Map<String, dynamic> _$FirebaseNotificationToJson(
+  FirebaseNotification instance,
+) => <String, dynamic>{
+  'stringify': instance.stringify,
+  'hashCode': instance.hashCode,
+  'title': instance.title,
+  'body': instance.body,
+  'image': instance.image,
+  'props': instance.props,
+};
diff --git a/lib/src/models/push_notification/onesignal_request_body.dart b/lib/src/models/push_notification/onesignal_request_body.dart
new file mode 100644
index 00000000..3ee22289
--- /dev/null
+++ b/lib/src/models/push_notification/onesignal_request_body.dart
@@ -0,0 +1,58 @@
+import 'package:core/core.dart';
+import 'package:equatable/equatable.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'onesignal_request_body.g.dart';
+
+/// {@template onesignal_request_body}
+/// Represents the request body for the OneSignal /notifications endpoint.
+/// {@endtemplate}
+@JsonSerializable(
+  explicitToJson: true,
+  includeIfNull: false, // Do not include null fields in the JSON
+  checked: true,
+  fieldRename: FieldRename.snake,
+  createFactory: false,
+)
+class OneSignalRequestBody extends Equatable {
+  /// {@macro onesignal_request_body}
+  const OneSignalRequestBody({
+    required this.appId,
+    required this.includePlayerIds,
+    required this.headings,
+    required this.data,
+    this.contents,
+    this.bigPicture,
+  });
+
+  /// The OneSignal App ID.
+  final String appId;
+
+  /// A list of OneSignal Player IDs to send the notification to.
+  final List<String> includePlayerIds;
+
+  /// The notification's title.
+  final Map<String, String> headings;
+
+  /// The notification's content.
+  final Map<String, String>? contents;
+
+  /// The custom data payload
+  final PushNotificationPayload data;
+
+  /// The URL of a large image to display in the notification.
+  final String? bigPicture;
+
+  /// Converts this [OneSignalRequestBody] instance to a JSON map.
+  Map<String, dynamic> toJson() => _$OneSignalRequestBodyToJson(this);
+
+  @override
+  List<Object?> get props => [
+    appId,
+    includePlayerIds,
+    headings,
+    contents,
+    data,
+    bigPicture,
+  ];
+}
diff --git a/lib/src/models/push_notification/onesignal_request_body.g.dart b/lib/src/models/push_notification/onesignal_request_body.g.dart
new file mode 100644
index 00000000..aa0b00a6
--- /dev/null
+++ b/lib/src/models/push_notification/onesignal_request_body.g.dart
@@ -0,0 +1,21 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'onesignal_request_body.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+Map<String, dynamic> _$OneSignalRequestBodyToJson(
+  OneSignalRequestBody instance,
+) => <String, dynamic>{
+  'stringify': ?instance.stringify,
+  'hash_code': instance.hashCode,
+  'app_id': instance.appId,
+  'include_player_ids': instance.includePlayerIds,
+  'headings': instance.headings,
+  'contents': ?instance.contents,
+  'data': instance.data.toJson(),
+  'big_picture': ?instance.bigPicture,
+  'props': instance.props,
+};
diff --git a/lib/src/models/push_notification/push_notification.dart b/lib/src/models/push_notification/push_notification.dart
new file mode 100644
index 00000000..0d93a137
--- /dev/null
+++ b/lib/src/models/push_notification/push_notification.dart
@@ -0,0 +1,2 @@
+export 'firebase_request_body.dart';
+export 'onesignal_request_body.dart';
diff --git a/lib/src/rbac/permissions.dart b/lib/src/rbac/permissions.dart
index 307f68cf..58761c63 100644
--- a/lib/src/rbac/permissions.dart
+++ b/lib/src/rbac/permissions.dart
@@ -50,9 +50,8 @@ abstract class Permissions {
   static const String userUpdate = 'user.update';
 
   // User App Settings Permissions (User-owned)
-  static const String userAppSettingsReadOwned = 'user_app_settings.read_owned';
-  static const String userAppSettingsUpdateOwned =
-      'user_app_settings.update_owned';
+  static const String appSettingsReadOwned = 'app_settings.read_owned';
+  static const String appSettingsUpdateOwned = 'app_settings.update_owned';
 
   // User Content Preferences Permissions (User-owned)
   static const String userContentPreferencesReadOwned =
diff --git a/lib/src/rbac/role_permissions.dart b/lib/src/rbac/role_permissions.dart
index eb3d5818..96b77a75 100644
--- a/lib/src/rbac/role_permissions.dart
+++ b/lib/src/rbac/role_permissions.dart
@@ -9,8 +9,8 @@ final Set<String> _appGuestUserPermissions = {
   Permissions.sourceRead,
   Permissions.countryRead,
   Permissions.languageRead,
-  Permissions.userAppSettingsReadOwned,
-  Permissions.userAppSettingsUpdateOwned,
+  Permissions.appSettingsReadOwned,
+  Permissions.appSettingsUpdateOwned,
   Permissions.userContentPreferencesReadOwned,
   Permissions.userContentPreferencesUpdateOwned,
   Permissions.remoteConfigRead,
diff --git a/lib/src/registry/data_operation_registry.dart b/lib/src/registry/data_operation_registry.dart
index 78047e73..b4fbc60f 100644
--- a/lib/src/registry/data_operation_registry.dart
+++ b/lib/src/registry/data_operation_registry.dart
@@ -113,8 +113,8 @@ class DataOperationRegistry {
           c.read<DataRepository<Language>>().read(id: id, userId: null),
       'user': (c, id) =>
           c.read<DataRepository<User>>().read(id: id, userId: null),
-      'user_app_settings': (c, id) =>
-          c.read<DataRepository<UserAppSettings>>().read(id: id, userId: null),
+      'app_settings': (c, id) =>
+          c.read<DataRepository<AppSettings>>().read(id: id, userId: null),
       'user_content_preferences': (c, id) => c
           .read<DataRepository<UserContentPreferences>>()
           .read(id: id, userId: null),
@@ -389,9 +389,9 @@ class DataOperationRegistry {
           userId: uid,
         );
       },
-      'user_app_settings': (c, id, item, uid) => c
-          .read<DataRepository<UserAppSettings>>()
-          .update(id: id, item: item as UserAppSettings, userId: uid),
+      'app_settings': (c, id, item, uid) => c
+          .read<DataRepository<AppSettings>>()
+          .update(id: id, item: item as AppSettings, userId: uid),
       'user_content_preferences': (context, id, item, uid) async {
         _log.info(
           'Executing custom updater for user_content_preferences ID: $id.',
@@ -454,8 +454,8 @@ class DataOperationRegistry {
           c.read<DataRepository<Country>>().delete(id: id, userId: uid),
       'language': (c, id, uid) =>
           c.read<DataRepository<Language>>().delete(id: id, userId: uid),
-      'user_app_settings': (c, id, uid) =>
-          c.read<DataRepository<UserAppSettings>>().delete(id: id, userId: uid),
+      'app_settings': (c, id, uid) =>
+          c.read<DataRepository<AppSettings>>().delete(id: id, userId: uid),
       'user_content_preferences': (c, id, uid) => c
           .read<DataRepository<UserContentPreferences>>()
           .delete(id: id, userId: uid),
diff --git a/lib/src/registry/model_registry.dart b/lib/src/registry/model_registry.dart
index 58a258bb..bf07f048 100644
--- a/lib/src/registry/model_registry.dart
+++ b/lib/src/registry/model_registry.dart
@@ -305,37 +305,36 @@ final modelRegistry = <String, ModelConfig<dynamic>>{
       type: RequiredPermissionType.unsupported,
     ),
   ),
-  'user_app_settings': ModelConfig<UserAppSettings>(
-    fromJson: UserAppSettings.fromJson,
+  'app_settings': ModelConfig<AppSettings>(
+    fromJson: AppSettings.fromJson,
     getId: (s) => s.id,
-    getOwnerId: (dynamic item) =>
-        (item as UserAppSettings).id as String?, // User ID is the owner ID
+    getOwnerId: (dynamic item) => (item as AppSettings).id,
     getCollectionPermission: const ModelActionPermission(
       type: RequiredPermissionType.unsupported, // Not accessible via collection
       requiresAuthentication: true,
     ),
     getItemPermission: const ModelActionPermission(
       type: RequiredPermissionType.specificPermission,
-      permission: Permissions.userAppSettingsReadOwned,
+      permission: Permissions.appSettingsReadOwned,
       requiresOwnershipCheck: true,
       requiresAuthentication: true,
     ),
     postPermission: const ModelActionPermission(
       type: RequiredPermissionType.unsupported,
       requiresAuthentication: true,
-      // Creation of UserAppSettings is handled by the authentication service
+      // Creation of AppSettings is handled by the authentication service
       // during user creation, not via a direct POST to /api/v1/data.
     ),
     putPermission: const ModelActionPermission(
       type: RequiredPermissionType.specificPermission,
-      permission: Permissions.userAppSettingsUpdateOwned,
+      permission: Permissions.appSettingsUpdateOwned,
       requiresOwnershipCheck: true,
       requiresAuthentication: true,
     ),
     deletePermission: const ModelActionPermission(
       type: RequiredPermissionType.unsupported,
       requiresAuthentication: true,
-      // Deletion of UserAppSettings is handled by the authentication service
+      // Deletion of AppSettings is handled by the authentication service
       // during account deletion, not via a direct DELETE to /api/v1/data.
     ),
   ),
diff --git a/lib/src/services/auth_service.dart b/lib/src/services/auth_service.dart
index 1b65484b..fe70e34e 100644
--- a/lib/src/services/auth_service.dart
+++ b/lib/src/services/auth_service.dart
@@ -26,7 +26,7 @@ class AuthService {
     required AuthTokenService authTokenService,
     required VerificationCodeStorageService verificationCodeStorageService,
     required EmailRepository emailRepository,
-    required DataRepository<UserAppSettings> userAppSettingsRepository,
+    required DataRepository<AppSettings> appSettingsRepository,
     required DataRepository<UserContentPreferences>
     userContentPreferencesRepository,
     required PermissionService permissionService,
@@ -36,7 +36,7 @@ class AuthService {
        _verificationCodeStorageService = verificationCodeStorageService,
        _permissionService = permissionService,
        _emailRepository = emailRepository,
-       _userAppSettingsRepository = userAppSettingsRepository,
+       _appSettingsRepository = appSettingsRepository,
        _userContentPreferencesRepository = userContentPreferencesRepository,
        _log = log;
 
@@ -44,7 +44,7 @@ class AuthService {
   final AuthTokenService _authTokenService;
   final VerificationCodeStorageService _verificationCodeStorageService;
   final EmailRepository _emailRepository;
-  final DataRepository<UserAppSettings> _userAppSettingsRepository;
+  final DataRepository<AppSettings> _appSettingsRepository;
   final DataRepository<UserContentPreferences>
   _userContentPreferencesRepository;
   final PermissionService _permissionService;
@@ -450,8 +450,8 @@ class AuthService {
       // 1. Explicitly delete associated user data. Unlike relational databases
       // with CASCADE constraints, MongoDB requires manual deletion of related
       // documents in different collections.
-      await _userAppSettingsRepository.delete(id: userId, userId: userId);
-      _log.info('Deleted UserAppSettings for user ${userToDelete.id}.');
+      await _appSettingsRepository.delete(id: userId, userId: userId);
+      _log.info('Deleted AppSettings for user ${userToDelete.id}.');
 
       await _userContentPreferencesRepository.delete(
         id: userId,
@@ -513,14 +513,14 @@ class AuthService {
   /// who might have been created before these documents were part of the standard
   /// user creation process.
   Future<void> _ensureUserDataExists(User user) async {
-    // Check for UserAppSettings
+    // Check for AppSettings
     try {
-      await _userAppSettingsRepository.read(id: user.id, userId: user.id);
+      await _appSettingsRepository.read(id: user.id, userId: user.id);
     } on NotFoundException {
       _log.info(
-        'UserAppSettings not found for user ${user.id}. Creating with defaults.',
+        'AppSettings not found for user ${user.id}. Creating with defaults.',
       );
-      final defaultAppSettings = UserAppSettings(
+      final defaultAppSettings = AppSettings(
         id: user.id,
         displaySettings: const DisplaySettings(
           baseTheme: AppBaseTheme.system,
@@ -535,14 +535,13 @@ class AuthService {
             'Default language "en" not found in language fixtures.',
           ),
         ),
-        feedPreferences: const FeedDisplayPreferences(
-          headlineDensity: HeadlineDensity.standard,
-          headlineImageStyle: HeadlineImageStyle.smallThumbnail,
-          showSourceInHeadlineFeed: true,
-          showPublishDateInHeadlineFeed: true,
+        feedSettings: const FeedSettings(
+          feedItemDensity: FeedItemDensity.standard,
+          feedItemImageStyle: FeedItemImageStyle.smallThumbnail,
+          feedItemClickBehavior: FeedItemClickBehavior.internalNavigation,
         ),
       );
-      await _userAppSettingsRepository.create(
+      await _appSettingsRepository.create(
         item: defaultAppSettings,
         userId: user.id,
       );
diff --git a/lib/src/services/database_seeding_service.dart b/lib/src/services/database_seeding_service.dart
index 7180980c..2d1eff25 100644
--- a/lib/src/services/database_seeding_service.dart
+++ b/lib/src/services/database_seeding_service.dart
@@ -122,14 +122,16 @@ class DatabaseSeedingService {
 
         // Ensure primaryAdPlatform is not 'demo' for initial setup
         // since its not intended for any use outside the mobile client.
-        final productionReadyAdConfig = initialConfig.adConfig.copyWith(
+        final productionReadyAdConfig = initialConfig.features.ads.copyWith(
           primaryAdPlatform: AdPlatformType.admob,
         );
 
         final productionReadyConfig = initialConfig.copyWith(
-          adConfig: productionReadyAdConfig,
           createdAt: DateTime.now(),
           updatedAt: DateTime.now(),
+          features: initialConfig.features.copyWith(
+            ads: productionReadyAdConfig,
+          ),
         );
 
         await remoteConfigCollection.insertOne({
@@ -357,9 +359,7 @@ class DatabaseSeedingService {
   /// Deletes a user and their associated sub-documents.
   Future<void> _deleteUserAndData(ObjectId userId) async {
     await _db.collection('users').deleteOne(where.eq('_id', userId));
-    await _db
-        .collection('user_app_settings')
-        .deleteOne(where.eq('_id', userId));
+    await _db.collection('app_settings').deleteOne(where.eq('_id', userId));
     await _db
         .collection('user_content_preferences')
         .deleteOne(where.eq('_id', userId));
@@ -368,7 +368,7 @@ class DatabaseSeedingService {
 
   /// Creates the default sub-documents (settings, preferences) for a new user.
   Future<void> _createUserSubDocuments(ObjectId userId) async {
-    final defaultAppSettings = UserAppSettings(
+    final defaultAppSettings = AppSettings(
       id: userId.oid,
       displaySettings: const DisplaySettings(
         baseTheme: AppBaseTheme.system,
@@ -383,14 +383,13 @@ class DatabaseSeedingService {
           'Default language "en" not found in language fixtures.',
         ),
       ),
-      feedPreferences: const FeedDisplayPreferences(
-        headlineDensity: HeadlineDensity.standard,
-        headlineImageStyle: HeadlineImageStyle.smallThumbnail,
-        showSourceInHeadlineFeed: true,
-        showPublishDateInHeadlineFeed: true,
+      feedSettings: const FeedSettings(
+        feedItemDensity: FeedItemDensity.standard,
+        feedItemImageStyle: FeedItemImageStyle.smallThumbnail,
+        feedItemClickBehavior: FeedItemClickBehavior.internalNavigation,
       ),
     );
-    await _db.collection('user_app_settings').insertOne({
+    await _db.collection('app_settings').insertOne({
       '_id': userId,
       ...defaultAppSettings.toJson()..remove('id'),
     });
diff --git a/lib/src/services/default_user_preference_limit_service.dart b/lib/src/services/default_user_preference_limit_service.dart
index e182cca8..8b952802 100644
--- a/lib/src/services/default_user_preference_limit_service.dart
+++ b/lib/src/services/default_user_preference_limit_service.dart
@@ -33,7 +33,7 @@ class DefaultUserPreferenceLimitService implements UserPreferenceLimitService {
     final remoteConfig = await _remoteConfigRepository.read(
       id: _remoteConfigId,
     );
-    final limits = remoteConfig.userPreferenceConfig;
+    final limits = remoteConfig.user.limits;
 
     // Retrieve all relevant limits for the user's role from the remote configuration.
     final (
@@ -204,26 +204,26 @@ class DefaultUserPreferenceLimitService implements UserPreferenceLimitService {
   )
   _getLimitsForRole(
     AppUserRole role,
-    UserPreferenceConfig limits,
+    UserLimitsConfig limits,
   ) {
-    final followedItemsLimit = limits.followedItemsLimit[role];
+    final followedItemsLimit = limits.followedItems[role];
     if (followedItemsLimit == null) {
       throw StateError('Followed items limit not configured for role: $role');
     }
 
-    final savedHeadlinesLimit = limits.savedHeadlinesLimit[role];
+    final savedHeadlinesLimit = limits.savedHeadlines[role];
     if (savedHeadlinesLimit == null) {
       throw StateError('Saved headlines limit not configured for role: $role');
     }
 
-    final savedHeadlineFiltersLimit = limits.savedHeadlineFiltersLimit[role];
+    final savedHeadlineFiltersLimit = limits.savedHeadlineFilters[role];
     if (savedHeadlineFiltersLimit == null) {
       throw StateError(
         'Saved headline filters limit not configured for role: $role',
       );
     }
 
-    final savedSourceFiltersLimit = limits.savedSourceFiltersLimit[role];
+    final savedSourceFiltersLimit = limits.savedSourceFilters[role];
     if (savedSourceFiltersLimit == null) {
       throw StateError(
         'Saved source filters limit not configured for role: $role',
diff --git a/lib/src/services/firebase_push_notification_client.dart b/lib/src/services/firebase_push_notification_client.dart
index d4135e6f..bba02380 100644
--- a/lib/src/services/firebase_push_notification_client.dart
+++ b/lib/src/services/firebase_push_notification_client.dart
@@ -1,4 +1,5 @@
 import 'package:core/core.dart';
+import 'package:flutter_news_app_api_server_full_source_code/src/models/models.dart';
 import 'package:flutter_news_app_api_server_full_source_code/src/services/push_notification_client.dart';
 import 'package:http_client/http_client.dart';
 import 'package:logging/logging.dart';
@@ -110,17 +111,16 @@ class FirebasePushNotificationClient implements IPushNotificationClient {
 
     // Create a list of futures, one for each notification to be sent.
     final sendFutures = deviceTokens.map((token) {
-      final requestBody = {
-        'message': {
-          'token': token,
-          'notification': {
-            'title': payload.title,
-            'body': payload.body,
-            if (payload.imageUrl != null) 'image': payload.imageUrl,
-          },
-          'data': payload.data,
-        },
-      };
+      final requestBody = FirebaseRequestBody(
+        message: FirebaseMessage(
+          token: token,
+          notification: FirebaseNotification(
+            title: payload.title,
+            image: payload.imageUrl,
+          ),
+          data: payload,
+        ),
+      );
 
       // Return the future from the post request.
       return _httpClient.post<void>(url, data: requestBody);
diff --git a/lib/src/services/onesignal_push_notification_client.dart b/lib/src/services/onesignal_push_notification_client.dart
index 47f3251c..1a49350f 100644
--- a/lib/src/services/onesignal_push_notification_client.dart
+++ b/lib/src/services/onesignal_push_notification_client.dart
@@ -1,4 +1,5 @@
 import 'package:core/core.dart';
+import 'package:flutter_news_app_api_server_full_source_code/src/models/models.dart';
 import 'package:flutter_news_app_api_server_full_source_code/src/services/push_notification_client.dart';
 import 'package:http_client/http_client.dart';
 import 'package:logging/logging.dart';
@@ -94,20 +95,18 @@ class OneSignalPushNotificationClient implements IPushNotificationClient {
     // app_dependencies.dart. The final URL will be: `https://onesignal.com/api/v1/notifications`
     const url = 'notifications';
 
-    // Construct the OneSignal API request body.
-    final requestBody = {
-      'app_id': appId,
-      'include_player_ids': deviceTokens,
-      'headings': {'en': payload.title},
-      'contents': {'en': payload.body},
-      if (payload.imageUrl != null) 'big_picture': payload.imageUrl,
-      'data': payload.data,
-    };
-
     _log.finer(
       'Sending OneSignal batch of ${deviceTokens.length} notifications.',
     );
 
+    final requestBody = OneSignalRequestBody(
+      appId: appId,
+      includePlayerIds: deviceTokens,
+      headings: {'en': payload.title},
+      bigPicture: payload.imageUrl,
+      data: payload,
+    );
+
     try {
       // The OneSignal API returns a JSON object with details about the send,
       // including errors for invalid player IDs.
diff --git a/lib/src/services/push_notification_service.dart b/lib/src/services/push_notification_service.dart
index dcdf0395..35230993 100644
--- a/lib/src/services/push_notification_service.dart
+++ b/lib/src/services/push_notification_service.dart
@@ -75,7 +75,7 @@ class DefaultPushNotificationService implements IPushNotificationService {
       final remoteConfig = await _remoteConfigRepository.read(
         id: _remoteConfigId,
       );
-      final pushConfig = remoteConfig.pushNotificationConfig;
+      final pushConfig = remoteConfig.features.pushNotifications;
 
       // Check if push notifications are globally enabled.
       if (!pushConfig.enabled) {
@@ -211,16 +211,14 @@ class DefaultPushNotificationService implements IPushNotificationService {
             id: notificationId.oid,
             userId: userId,
             payload: PushNotificationPayload(
+              // Corrected payload structure
               title: headline.title,
-              body: headline.excerpt,
               imageUrl: headline.imageUrl,
-              data: {
-                'notificationType':
-                    PushNotificationSubscriptionDeliveryType.breakingOnly.name,
-                'contentType': 'headline',
-                'headlineId': headline.id,
-                'notificationId': notificationId.oid,
-              },
+              notificationId: notificationId.oid,
+              notificationType:
+                  PushNotificationSubscriptionDeliveryType.breakingOnly,
+              contentType: ContentType.headline,
+              contentId: headline.id,
             ),
             createdAt: DateTime.now(),
           );
diff --git a/pubspec.lock b/pubspec.lock
index 44a50785..780b3c05 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -5,10 +5,10 @@ packages:
     dependency: transitive
     description:
       name: _fe_analyzer_shared
-      sha256: c209688d9f5a5f26b2fb47a188131a6fb9e876ae9e47af3737c0b4f58a93470d
+      sha256: "5b7468c326d2f8a4f630056404ca0d291ade42918f4a3c6233618e724f39da8e"
       url: "https://pub.dev"
     source: hosted
-    version: "91.0.0"
+    version: "92.0.0"
   adaptive_number:
     dependency: transitive
     description:
@@ -21,10 +21,10 @@ packages:
     dependency: transitive
     description:
       name: analyzer
-      sha256: f51c8499b35f9b26820cfe914828a6a98a94efd5cc78b37bb7d03debae3a1d08
+      sha256: "70e4b1ef8003c64793a9e268a551a82869a8a96f39deb73dea28084b0e8bf75e"
       url: "https://pub.dev"
     source: hosted
-    version: "8.4.1"
+    version: "9.0.0"
   archive:
     dependency: transitive
     description:
@@ -81,6 +81,62 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.2.3"
+  build:
+    dependency: transitive
+    description:
+      name: build
+      sha256: c1668065e9ba04752570ad7e038288559d1e2ca5c6d0131c0f5f55e39e777413
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.0.3"
+  build_config:
+    dependency: transitive
+    description:
+      name: build_config
+      sha256: "4f64382b97504dc2fcdf487d5aae33418e08b4703fc21249e4db6d804a4d0187"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.2.0"
+  build_daemon:
+    dependency: transitive
+    description:
+      name: build_daemon
+      sha256: bf05f6e12cfea92d3c09308d7bcdab1906cd8a179b023269eed00c071004b957
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.1.1"
+  build_runner:
+    dependency: "direct dev"
+    description:
+      name: build_runner
+      sha256: "110c56ef29b5eb367b4d17fc79375fa8c18a6cd7acd92c05bb3986c17a079057"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.10.4"
+  built_collection:
+    dependency: transitive
+    description:
+      name: built_collection
+      sha256: "376e3dd27b51ea877c28d525560790aee2e6fbb5f20e2f85d5081027d94e2100"
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.1.1"
+  built_value:
+    dependency: transitive
+    description:
+      name: built_value
+      sha256: "426cf75afdb23aa74bd4e471704de3f9393f3c7b04c1e2d9c6f1073ae0b8b139"
+      url: "https://pub.dev"
+    source: hosted
+    version: "8.12.1"
+  checked_yaml:
+    dependency: transitive
+    description:
+      name: checked_yaml
+      sha256: "959525d3162f249993882720d52b7e0c833978df229be20702b33d48d91de70f"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.4"
   cli_config:
     dependency: transitive
     description:
@@ -97,6 +153,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.2"
+  code_builder:
+    dependency: transitive
+    description:
+      name: code_builder
+      sha256: "11654819532ba94c34de52ff5feb52bd81cba1de00ef2ed622fd50295f9d4243"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.11.0"
   collection:
     dependency: "direct main"
     description:
@@ -117,8 +181,8 @@ packages:
     dependency: "direct main"
     description:
       path: "."
-      ref: "064c4387b3f7df835565c41c918dc2d80dd2f49a"
-      resolved-ref: "064c4387b3f7df835565c41c918dc2d80dd2f49a"
+      ref: c0c41c069b885f0c16d1b134269aa06861634186
+      resolved-ref: c0c41c069b885f0c16d1b134269aa06861634186
       url: "https://github.com/flutter-news-app-full-source-code/core.git"
     source: git
     version: "1.3.1"
@@ -154,6 +218,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.3.1"
+  dart_style:
+    dependency: transitive
+    description:
+      name: dart_style
+      sha256: a9c30492da18ff84efe2422ba2d319a89942d93e58eb0b73d32abe822ef54b7b
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.3"
   data_client:
     dependency: "direct main"
     description:
@@ -296,6 +368,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.3"
+  graphs:
+    dependency: transitive
+    description:
+      name: graphs
+      sha256: "741bbf84165310a68ff28fe9e727332eef1407342fca52759cb21ad8177bb8d0"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.3.2"
   hotreloader:
     dependency: transitive
     description:
@@ -361,14 +441,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.5"
-  js:
-    dependency: transitive
-    description:
-      name: js
-      sha256: "53385261521cc4a0c4658fd0ad07a7d14591cf8fc33abbceae306ddb974888dc"
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.7.2"
   json_annotation:
     dependency: "direct main"
     description:
@@ -377,6 +449,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.9.0"
+  json_serializable:
+    dependency: "direct dev"
+    description:
+      name: json_serializable
+      sha256: "6b253f7851cf1626a05c8b49c792e04a14897349798c03798137f2b5f7e0b5b1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.11.3"
   logging:
     dependency: "direct main"
     description:
@@ -505,6 +585,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.2.0"
+  pubspec_parse:
+    dependency: transitive
+    description:
+      name: pubspec_parse
+      sha256: "0560ba233314abbed0a48a2956f7f022cce7c3e1e73df540277da7544cad4082"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.0"
   rational:
     dependency: transitive
     description:
@@ -577,6 +665,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.0.0"
+  source_gen:
+    dependency: transitive
+    description:
+      name: source_gen
+      sha256: "07b277b67e0096c45196cbddddf2d8c6ffc49342e88bf31d460ce04605ddac75"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.1.1"
+  source_helper:
+    dependency: transitive
+    description:
+      name: source_helper
+      sha256: e82b1996c63da42aa3e6a34cc1ec17427728a1baf72ed017717a5669a7123f0d
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.3.9"
   source_map_stack_trace:
     dependency: transitive
     description:
@@ -653,26 +757,26 @@ packages:
     dependency: "direct dev"
     description:
       name: test
-      sha256: "75906bf273541b676716d1ca7627a17e4c4070a3a16272b7a3dc7da3b9f3f6b7"
+      sha256: "77cc98ea27006c84e71a7356cf3daf9ddbde2d91d84f77dbfe64cf0e4d9611ae"
       url: "https://pub.dev"
     source: hosted
-    version: "1.26.3"
+    version: "1.28.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
-      sha256: ab2726c1a94d3176a45960b6234466ec367179b87dd74f1611adb1f3b5fb9d55
+      sha256: "19a78f63e83d3a61f00826d09bc2f60e191bf3504183c001262be6ac75589fb8"
       url: "https://pub.dev"
     source: hosted
-    version: "0.7.7"
+    version: "0.7.8"
   test_core:
     dependency: transitive
     description:
       name: test_core
-      sha256: "0cc24b5ff94b38d2ae73e1eb43cc302b77964fbf67abad1e296025b78deb53d0"
+      sha256: f1072617a6657e5fc09662e721307f7fb009b4ed89b19f47175d11d5254a62d4
       url: "https://pub.dev"
     source: hosted
-    version: "0.6.12"
+    version: "0.6.14"
   typed_data:
     dependency: transitive
     description:
diff --git a/pubspec.yaml b/pubspec.yaml
index d4eb70db..98ed31a7 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -52,6 +52,8 @@ dependencies:
   shelf_cors_headers: ^0.1.5
 
 dev_dependencies:
+  build_runner: ^2.10.4
+  json_serializable: ^6.11.3
   mocktail: ^1.0.3
   test: ^1.25.5
   very_good_analysis: ^9.0.0
@@ -60,7 +62,7 @@ dependency_overrides:
   core:
     git:
       url: https://github.com/flutter-news-app-full-source-code/core.git
-      ref: 064c4387b3f7df835565c41c918dc2d80dd2f49a
+      ref: c0c41c069b885f0c16d1b134269aa06861634186
   http_client:
     git:
       url: https://github.com/flutter-news-app-full-source-code/http-client.git
diff --git a/routes/_middleware.dart b/routes/_middleware.dart
index a0dfa9b3..21607b8c 100644
--- a/routes/_middleware.dart
+++ b/routes/_middleware.dart
@@ -115,8 +115,8 @@ Handler middleware(Handler handler) {
                 provider<DataRepository<User>>((_) => deps.userRepository),
               ) //
               .use(
-                provider<DataRepository<UserAppSettings>>(
-                  (_) => deps.userAppSettingsRepository,
+                provider<DataRepository<AppSettings>>(
+                  (_) => deps.appSettingsRepository,
                 ),
               )
               .use(