I am trying to migrate my Android app from GCM to FCM.
I use Google Cloud project for GCM and Firebase project for some Firebase features (Analytics, etc.) now.
Docs say that I need to import Google Cloud project to Firebase, but I already have Firebase project for my app.
As I understand, it is needed to provide GCM and FCM tokens compatibility.
So, how to link existing Firebase and Google Cloud projects?
If it is impossible, is it possible to send messages to old tokens using new FCM endpoints and which credentials (Google Cloud or Firebase) should be used for it?