Hi all, I am in the process of preparing for an app transfer, and have sign-in with apple enabled. I have read the documentation thoroughly and multiple times, yet there are a few things I'd like to have a confirmation about, before taking the leap and risking that some users might experience any issues. If I understand correctly, after the migration if a user performs a sign-in with Apple, they will send an access_token that differs from the one they were sending when the app was assigned to the old team. In case I didn't take any action that means that my system would think this was a new user given the access_token has never been seen before, and therefore it will create a new user. Is that correct? Ok, so if that assumption is correct, I'd like to have a confirmation also of the way I intend to fix this, since we're doing an internal transfer and the database is going to be the same. I would get a TransferID for all users in my database that have used sign-in with Apple (I have already done that for one of my test users, successfully). After that, I will start the transfer, and accept it from the other team. Once that is done, I will call the migrationinfo endpoint from the other team, getting all the new access_tokens related to the transfer ids. With that information, I will update my databse, adding a relation from the new access token from team B that points to the same user as the access token that was given by team A, and I know which one it is because of the TransferID. Does that make sense? Would it work? I'm not a fan of messing with the login logic (having a look at transfer_ids, looking for matches, and so on), especially because there doesn't seem to be a way to test this. I believe the only risk is that a user might login after the app has been transferred but before I can upload the new access token to the database, but we can handle these (few, hopefully even zero cases) via ticketing. These are the resources I have read so far: https://developer.apple.com/documentation/technotes/tn3159-migrating-sign-in-with-apple-users-for-an-app-transfer#Preparing-to-migrate-users-for-an-app-transfer https://developer.apple.com/documentation/sign_in_with_apple/transferring_your_apps_and_users_to_another_team#3546291 https://developer.apple.com/documentation/sign_in_with_apple/bringing_new_apps_and_users_into_your_team My last question is: how can I test this before going live? Do I really have to just implement changes/update the DB and then go live, hoping that it will all work? Can't I do some sandbox transfer or anything like that? Even just creating like a "clone" of my app and transferring this one would be a huge boost for the confidence of this big leap. Thanks in advance.