I have almost the same problem. I made a build using an online platform yesterday with this Xcode version:
Xcode 15.0.1 (Build version 15A507)
Then that platform sent the build to the Testflight and I can download and test the app on my iPhone.
Now that I want to add more tester groups, I get this error:
This build is using a beta version of Xcode and can’t be submitted. Make sure you’re using the latest version of Xcode or the latest seed release found on the releases tab in News and Updates
HosseinRashnoDev
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