TestFlight not possible with BigSur

Targets macOS
1

So, after downloading once more new Apple Certificates and creating a new Tester (myself) I was happy when after delivering the app to the Store, Transporter did not warn that I could not testflight the app.

Yet, in the TestFlight section of the Store, it says that the app is not eligible for TestFlight. In fact I came to know that TestFlight App is available for Monterey only.

Therefore, since my MBP is using BigSur and cant upgrade to Monterey, BigSur users are cat off from TestFlight.
It also means that BigSur users cannot test the apps to be delivered to the Store as they used to do, because the old procedure (launching the app and getting the prompt to enter login & pw) returns a message that the app is corrupt.

Any other way to pre-test the apps without buying a new Mac?

BTW: I do not need any other pre-tester; just myself.

Thanks.

2

You could try to mark your application as “Development” release, so the Sandbox testers are active again…
Apple says: “Your development signed apps use the sandbox environment when you sign in to the App Store with a sandboxed Apple ID.” (https://appstoreconnect.apple.com/access/testers)

3

The idea was/is to have on disk exactly the same app on the Store.
Thanks for answering.