I used to upgrade my other APP from GCM to FCM, and when the user already installed the App on their device, the first time they open after migration, I assumed they get FCM token that is different from the original GCM token (Sorry I'm not very sure, it's a long time ago). In that App, the FCM version is 11.8.0.
And now in my current migrating App, I'm migrating from GCM to the latest FCM version which is 17.3.4. When I tried to just copy and paste my code, I found out I need to make some arrangements along the way. So I followed: FirebaseInstanceIdService is deprecated and Firebase (FCM) how to get token.
But now the tester in our company told me the new FCM token I send to the server is the same as the old GCM token. Just wondering if this is normal or not, I don't see anyone asking the same question and just trying to make sure I didn't miss anything or do something wrong, thanks in advance.