How to keep Sign in with Apple users signed in after app transfer?

I'm currently transferring an iOS app to a new Apple Developer account and following the process outlined in Apple’s documentation:

🔗 TN3159 - Migrating Sign in with Apple users for an app transfer

The process for generating transfer_identifiers and migrating existing users is clear, and I don’t expect issues with that part.

However, I have a question about preserving the user session after the transfer.

My setup:

  • The app uses Sign in with Apple via a backend-based authentication flow.

  • On login, the app retrieves the authorization_code and sends it to the backend.

  • The backend exchanges the code for tokens from Apple, including a refresh_token.

  • That refresh_token is then used on the backend to validate the user’s identity on subsequent requests.

My concern:

Once I initiate the app transfer, migrate users, and update the backend with new Apple credentials (client ID, team ID, etc.), I assume that the existing tokens issued under the old credentials will become invalid.

So my question is: Is there a way to maintain the user’s authenticated session through this transition without requiring them to manually sign in again?

I’d like to ensure a seamless experience for users, if possible.

How to keep Sign in with Apple users signed in after app transfer?
 
 
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