diff --git a/android/app/google-services.json b/android/app/google-services.json
new file mode 100644
index 0000000..fd777d5
--- /dev/null
+++ b/android/app/google-services.json
@@ -0,0 +1,29 @@
+{
+  "project_info": {
+    "project_number": "988487669355",
+    "project_id": "otthonnaptar-b9e74",
+    "storage_bucket": "otthonnaptar-b9e74.firebasestorage.app"
+  },
+  "client": [
+    {
+      "client_info": {
+        "mobilesdk_app_id": "1:988487669355:android:a74debf7d71bb37d49c32e",
+        "android_client_info": {
+          "package_name": "hu.otthonnaptar.otthon_naptar"
+        }
+      },
+      "oauth_client": [],
+      "api_key": [
+        {
+          "current_key": "AIzaSyBhoH8a2CxYZbwoEPllg-EoO0mGI0fW-jw"
+        }
+      ],
+      "services": {
+        "appinvite_service": {
+          "other_platform_oauth_client": []
+        }
+      }
+    }
+  ],
+  "configuration_version": "1"
+}
\ No newline at end of file
diff --git a/lib/app_shell.dart b/lib/app_shell.dart
index 4644b04..7f7d624 100644
--- a/lib/app_shell.dart
+++ b/lib/app_shell.dart
@@ -15,6 +15,7 @@ class _OtthonAppState extends State<OtthonApp> {
   List<CalendarEvent> syncedEvents = [];
   List<String> todoSuggestions = [];
   JarvisSettings jarvisSettings = JarvisSettings.defaults();
+  String googleServerClientId = googleCalendarServerClientId;
   WeatherSnapshot? weather;
   String themeId = 'sage';
   bool loaded = false;
@@ -40,9 +41,11 @@ class _OtthonAppState extends State<OtthonApp> {
       syncedEvents = settings.syncedEvents;
       todoSuggestions = settings.todoSuggestions;
       jarvisSettings = settings.jarvisSettings;
+      googleServerClientId = settings.googleServerClientId;
       themeId = settings.themeId;
       loaded = true;
     });
+    _loadRemoteAppConfig();
   }
 
   Future<void> _saveSettings() async {
@@ -54,10 +57,39 @@ class _OtthonAppState extends State<OtthonApp> {
         syncedEvents: syncedEvents,
         todoSuggestions: todoSuggestions,
         jarvisSettings: jarvisSettings,
+        googleServerClientId: googleServerClientId,
       ),
     );
   }
 
+  Future<void> _loadRemoteAppConfig() async {
+    final apiToken = jarvisSettings.apiToken.trim();
+    if (apiToken.isEmpty) return;
+
+    try {
+      final baseUri = Uri.parse(normalizeJarvisUrl(jarvisSettings.apiUrl));
+      final uri = baseUri.replace(path: '/api/app-config', query: '');
+      final response = await http
+          .get(uri, headers: {'X-Otthon-Token': apiToken})
+          .timeout(const Duration(seconds: 10));
+      if (response.statusCode != 200) return;
+      final payload = jsonDecode(response.body);
+      if (payload is! Map<String, dynamic>) return;
+      final remoteGoogleClientId =
+          payload['googleCalendarServerClientId'] as String?;
+      if (remoteGoogleClientId == null ||
+          remoteGoogleClientId.trim().isEmpty ||
+          remoteGoogleClientId == googleServerClientId) {
+        return;
+      }
+      if (!mounted) return;
+      setState(() => googleServerClientId = remoteGoogleClientId.trim());
+      _saveSettings();
+    } catch (_) {
+      // Offline mode keeps the locally cached app configuration.
+    }
+  }
+
   void _updatePeople(List<Person> nextPeople) {
     setState(() => people = nextPeople);
     _saveSettings();
@@ -88,6 +120,7 @@ class _OtthonAppState extends State<OtthonApp> {
   void _updateJarvisSettings(JarvisSettings nextSettings) {
     setState(() => jarvisSettings = nextSettings);
     _saveSettings();
+    _loadRemoteAppConfig();
   }
 
   Future<void> _loadWeather() async {
@@ -132,6 +165,7 @@ class _OtthonAppState extends State<OtthonApp> {
         syncedEvents: syncedEvents,
         todoSuggestions: todoSuggestions,
         jarvisSettings: jarvisSettings,
+        googleServerClientId: googleServerClientId,
         weather: weather,
         themeId: themeId,
         loaded: loaded,
@@ -154,6 +188,7 @@ class HomeShell extends StatefulWidget {
     required this.syncedEvents,
     required this.todoSuggestions,
     required this.jarvisSettings,
+    required this.googleServerClientId,
     required this.weather,
     required this.themeId,
     required this.loaded,
@@ -170,6 +205,7 @@ class HomeShell extends StatefulWidget {
   final List<CalendarEvent> syncedEvents;
   final List<String> todoSuggestions;
   final JarvisSettings jarvisSettings;
+  final String googleServerClientId;
   final WeatherSnapshot? weather;
   final String themeId;
   final bool loaded;
@@ -352,6 +388,7 @@ class _HomeShellState extends State<HomeShell> {
           cachedEvents: widget.syncedEvents,
           people: widget.people,
           jarvisSettings: widget.jarvisSettings,
+          serverClientId: widget.googleServerClientId,
           onChanged: widget.onGoogleConnectionsChanged,
           onSyncedEventsChanged: widget.onSyncedEventsChanged,
         ),
diff --git a/lib/data.dart b/lib/data.dart
index 033043f..54639c5 100644
--- a/lib/data.dart
+++ b/lib/data.dart
@@ -125,6 +125,7 @@ class AppJsonStore {
           syncedEvents: const [],
           todoSuggestions: const [],
           jarvisSettings: JarvisSettings.defaults(),
+          googleServerClientId: googleCalendarServerClientId,
         );
         await save(settings);
         return settings;
@@ -141,6 +142,7 @@ class AppJsonStore {
         syncedEvents: const [],
         todoSuggestions: const [],
         jarvisSettings: JarvisSettings.defaults(),
+        googleServerClientId: googleCalendarServerClientId,
       );
     }
   }
@@ -161,6 +163,7 @@ class AppSettings {
     required this.syncedEvents,
     required this.todoSuggestions,
     required this.jarvisSettings,
+    required this.googleServerClientId,
   });
 
   final List<Person> people;
@@ -169,6 +172,7 @@ class AppSettings {
   final List<CalendarEvent> syncedEvents;
   final List<String> todoSuggestions;
   final JarvisSettings jarvisSettings;
+  final String googleServerClientId;
 
   factory AppSettings.fromJson(Map<String, dynamic> json) {
     final rawPeople = json['people'];
@@ -204,6 +208,8 @@ class AppSettings {
       jarvisSettings: rawJarvisSettings is Map<String, dynamic>
           ? JarvisSettings.fromJson(rawJarvisSettings)
           : JarvisSettings.defaults(),
+      googleServerClientId:
+          json['googleServerClientId'] as String? ?? googleCalendarServerClientId,
     );
   }
 
@@ -216,6 +222,7 @@ class AppSettings {
     'syncedEvents': syncedEvents.map((event) => event.toJson()).toList(),
     'todoSuggestions': todoSuggestions,
     'jarvisSettings': jarvisSettings.toJson(),
+    'googleServerClientId': googleServerClientId,
   };
 }
 
diff --git a/lib/google_calendar_page.dart b/lib/google_calendar_page.dart
index 7c7eb5a..e32e96b 100644
--- a/lib/google_calendar_page.dart
+++ b/lib/google_calendar_page.dart
@@ -7,6 +7,7 @@ class AccountsPage extends StatefulWidget {
     required this.cachedEvents,
     required this.people,
     required this.jarvisSettings,
+    required this.serverClientId,
     required this.onChanged,
     required this.onSyncedEventsChanged,
   });
@@ -15,6 +16,7 @@ class AccountsPage extends StatefulWidget {
   final List<CalendarEvent> cachedEvents;
   final List<Person> people;
   final JarvisSettings jarvisSettings;
+  final String serverClientId;
   final ValueChanged<List<GoogleCalendarConnection>> onChanged;
   final ValueChanged<List<CalendarEvent>> onSyncedEventsChanged;
 
@@ -51,9 +53,10 @@ class _AccountsPageState extends State<AccountsPage> {
       statusMessage = 'Google napt\u00e1rkapcsolat el\u0151k\u00e9sz\u00edt\u00e9se...';
     });
 
-    final configuredClientId = await _loadGoogleServerClientId();
+    runtimeServerClientId = widget.serverClientId.trim().isNotEmpty
+        ? widget.serverClientId.trim()
+        : await _loadGoogleServerClientId();
     if (!mounted) return;
-    runtimeServerClientId = configuredClientId?.trim();
     await _initializeGoogle();
   }
 
@@ -147,8 +150,9 @@ class _AccountsPageState extends State<AccountsPage> {
 
     try {
       if (!initialized) {
-        final configuredClientId = await _loadGoogleServerClientId();
-        runtimeServerClientId = configuredClientId?.trim();
+        runtimeServerClientId = widget.serverClientId.trim().isNotEmpty
+            ? widget.serverClientId.trim()
+            : await _loadGoogleServerClientId();
         await _ensureGoogleInitialized();
         initialized = true;
       }