Do I need to migrate GCM to FCM on client side?

Question

I have the old android app on Play Store which I am not going to update anymore because of making a new app.

Do I need to migrate GCM to FCM in my old andro

Answer 1

You need to update your client code and migrate to FCM. Because it is officially announced to do migration and it is very likely that from a point, for example by one of the android updates, they stop supporting old api callbacks and if so you will lose part of your users.

So my advice is to do the migration as it has been long enough so far that they had supported GCM along with supporting FCM and they can't and won't do it forever.