Hey,
Our team is currently evaluating transferring an App to our parent companies team account. We have obvious concerns around SIWA and want to make sure that user accounts will persist between publishers.
We have been reading the documentation here and it seems like there is a pretty well defined flow for this outlined here: https://developer.apple.com/documentation/sign_in_with_apple/transferring_your_apps_and_users_to_another_team
We would like to generate transfer_identifiers for all of our users before initiating the App Transfer but we are seeing conflicting information about whether this is possible.
From the docs it says:
After the recipient team accepts the transfer, you have 60 days to generate transfer identifiers for the client.
Which to me, can be a read a couple ways, but potentially suggests that we won't be able to generate the transfer identifiers until after initiating the transfer.
We also see in this post, potentially conflicting information from an Apple rep: https://developer.apple.com/forums/thread/649251
If you plan to transfer an app from your team to another team, you can generate a transfer identifier any time.
This clearly suggests that we should be able to generate transfer_identifiers at any time.
To verify one way or the other, we have attempted to generate transfer_identifiers before transferring our app to the parent team. While we have successfully generated auth_tokens with the rest API, we have not been able to get a successful response back from the transfer rest api at https://appleid.apple.com/auth/usermigrationinfo
So far we have only received the error: invalid_client
It would be appreciated if an Apple rep (or experienced user) can weigh in on whether this should be possible. If so, any pro tips on debugging the invalid_client response would also be very much appreciated.