Change Firebase project for production app with Google Authentication?

Question

I need to change Firebase Project of production app with google authentication.

My app is working with a firebase project and a backend server from which I can force users to update my app to the latest version after login with version the user has. Because of that, I hope I can change the Firebase project where I do the authentication with Google.

I can't use old pair Package Name / SHA-1 in new Firebase project, but I can use old package name with NEW SHA-1, right?

So, users with old versions will login with old firebase project and after upgrade my app they will login with with new firebase project, right?

If so, users won't need to uninstall my app, right?

Now, how can I change the SHA-1 in Android Studio?

Answer 1

What I understand you are trying to do is the following.

1. You want to associate your app to new firebase project
2. You want to keep you old user base intact.

You have asked if you can change the SHA-1 of the app the answer is no without changing the signature of the app that could change everything and is not an option.

What you could do instead is use two different firebase projects in a single app and write your own logic to manage the users. You can follow this link https://firebase.googleblog.com/2016/12/working-with-multiple-firebase-projects-in-an-android-app.html here the author has explained how to go about it.
you can also look up for similar solutions or arounds for the problem. Hope this helps in some way and please try to make you questions precise.