On June 30th (Apple just extended the deadline from 30th Apple) will start rejecting apps from the app store because of one change.
If you have a third-party login e.g. Facebook, Google, Twitter etc. Then unless you also add Sign in with Apple your app will start to be rejected and no longer meet their guidelines.
Sign in with Apple is a required change to any of those apps and you must implement it in any new apps or app updates after that date.
We’re now interesting times and some projects are on hold or moving slowly while others are continuing like normal. Everyone’s business is different but the requirement is the same.
The email from Apple might have been missed by your team in this current situation as we all have had an influx in emails of the last few weeks.
If you do have an app that supports this login please share this with your team if they haven’t brought it up. (I’ll put the link in the comments)
This is another classic example of external factors that force change in your project and why you must work flexibly. Not everything is in our control as we’ve seen in the last few weeks and things can change very quickly.