Achieving Background Notification Handling in Flutter Without Location Services

Question

I have a Flutter app integrated with Firebase Cloud Messaging (FCM) for real-time data transmission. The app handles background notifications and communicates with the main isolate. Currently, this functionality works only when location services are enabled, keeping the app awake. I understand that the background notifications are effectively processed because location services keep the app active. However, I need to achieve the same functionality without relying on location services.

Current Implementation:

Port Registration for Inter-Isolate Communication:

bool registerResult = IsolateNameServer.registerPortWithName(
    _receivePort.sendPort, "whatever");

if (!registerResult) {
  // Handling existing port registration
} else {
  // Port registered successfully
}

Handling Background Notifications:

@pragma('vm:entry-point')
static Future<void> _firebaseMessagingBackgroundHandler(
    RemoteMessage message) async {
  await Firebase.initializeApp();

  SendPort? sendPort = IsolateNameServer.lookupPortByName("whatever");
  if (sendPort != null) {
    sendPort.send(message.data);
  } else {
    // Handle null sendPort
  }
}

Issue:

The app does not process background notifications when location services are turned off. I need an alternative method to keep the app responsive to FCM background notifications without requiring location services to be active.

Question:

How can I ensure that my Flutter app remains responsive to FCM background notifications and communicates with the main isolate, similar to how it operates with location services, but without having to keep location services enabled?

What I've Tried:

The app functions as expected with location services enabled, implying background processing is active. Disabling location services leads to unprocessed background notifications.

Additional Context:

Flutter version: 3.13.2 Firebase Cloud Messaging version: ^14.7.8 Tested on: iPhone 11, iPhone 14 Pro

I am looking for strategies or Flutter-specific features that could help maintain background activity for FCM notifications without location services.