Thanks for your answer, Rich, my team is one of those who are using the local receipt validation just to check if the user downloaded our apps from the macOS Appstore, but:
DCAppAttestService is available for macOS 11 or newer. What should we do with older systems?
The documentation about local receipt validation (https://developer.apple.com/documentation/appstorereceipts/validating_receipts_on_the_device) isn't marked as deprecated and describes the process quite clear: If verification fails, exit with 173. This works for years and it even works sometimes for the last months. So don't you think it is a bug, that Apple should fix? Will Apple fix it?
Greetings
Brigitte