Our app stores some data to keychain , userdefaults or document directory storage as part of user registration process. This data help in determining the user registration status in subsequent launches and authenticate user.
Recently, 2 of our customer's device got auto updated to 16.7.2. User is unaware of this auto update but next time they launched the app, it asked them to register instead of allowing them login.
As per overall analysis of all aspect, We also suspect that OS update may have wiped out data from one of the storage location which is causing app to determine that user is not registered.
We need to conclude the RCA for our issue and if OS update may be a possibility, will need to release an advisory to all users of possible consequences and workaround.
Request your help to understand the possibility.