I'm having same problem. Any solutions for this? Another question, how did you set mime type of file?

Xcode 13.3 is not supported in OS X 10.15.7. Xcode 12.4's App Submission will be close to the App Store in the next 10-12 months. Till then I can use Xcode 12.4

Now I'm using Xcode 13.4 but still facing the same issue. I can not install on iOS 14 devices as well as I'm not able to install on iOS 15 devices. I've trusted "Xcode Server OTA Installation" but still facing issue.