The document from Google says:
GCM tokens retrieved via GoogleCloudMessaging.register() or
InstanceID.getToken() will continue to work in FCM without any
modification or renewal.
But when I update my APP to FCM. The old GCM token which stores in my Server does not work anymore. When I tried to send a push message, the Google Message server response the error message, not registered. Does anyone ran into the same problem?
Based from the documentation of GCM and FCM FAQ:
Will your existing GCM tokens and token handling still work?
Your GCM and FCM registration tokens are mutually interchangeable; you
can send to existing GCM tokens through the FCM HTTP server APIs. For
GCM and FCM token handling, remember:
- If you store and send to specific tokens, be sure to implement the token refresh method to ensure your tokens are always up to date
- iOS devs should avoid calling
.getToken(authorizedEntity,scope)
unless there is a need to enable multiple senders. Use
FirebaseInstanceId.getInstance().getToken()
instead.