When transferring an app from one team to another, Sign in with Apple users have to me carefuly migrated since their unique identifiers are team-scoped.
To migrate users from Team A to Team B, a transient transfer identifier, aka transfer_sub, has to be generated by Team A before the transfer to prepare the app data, using specific migration endpoints provided by Apple. "Preparing the app data" means, for example, associate database entries to the transfer id instead of the team-specific id.
One the app has been transferred, and during 60 days, Team B will find the transfer_sub in ID tokens issued by Apple Sign In, and thanks to this shared identifier they can retrieve the user data and associate it to their new unique identifier.
So far so good !
Now, the question : if an app is transferred from Team A to Team B, and then, shortly thereafter (a few days later), from team B to team C, will the transfer_sub related to the B-C transfer be different ? Or will they remain the same as the ones issued for the A-B transfer ?
(I'm asking this question in order to avoid the possible catastrophe of an ill-prepared double app transfer)
Thank you !
Hi @evergreen_herb,
You wrote:
[...] if an app is transferred from Team A to Team B, and then, shortly thereafter (a few days later), from team B to team C, will the transfer_sub related to the B-C transfer be different ? Or will they remain the same as the ones issued for the A-B transfer ?
The transfer IDs are bridged between the teams associated with the app transfer. So the transfer ID for a user associated with an app transferred between Team A and Team B will be different from the transfer ID for the same app transferred between Team B and Team C. However, if Team B instead transferred the app back to Team A, the existing transfer ID used between them (in the initial app transfer) would be valid.
Cheers,
Paris X Pinkney | WWDR | DTS Engineer
