Same problem here, pushed an update after testing on 14.5 and 15.0 - the most recent Simulators available in XCode 13.1. Now all my users on 14.6 - 14.8.1, are having problems, which I can't test against.
Just got new reports of problems on 15.1, but again, no SDK or Simulator available, and most online test platforms don't support these security-patch-only iOS versions.
What's the recommended solution to get these SDKs?