BTW, this class is marked @available(macOS 10.15, *) and the target is set to 10.12.

Interesting. If I change CheckedContinuation to UnsafeContinuation and also all withCheckedThrowingContinuation to withUnsafeThrowingContinuation, it now links.

MacBook Pro M1. But also happens on a build machine with Intel. macOS Ventura 13.5.

What would be the path if we stick to the same bundle ID but sign with a different certificate? Do we need to remove the identifier from one account and create it again in another account? We have bundle IDs such as com.xxxx.one-flavour for one BU and com.xxxx.other-flavour for the other BU. Could we in theory remove one flavour and recreate it in the other account (or transfer)? Also, if we did it this way, and the two BUs become separate companies, are there any implications (with respect to Apple's handling of identifiers) in differently named products having the same base domain name as part of the bundle ID?