I don't think we have ever claimed to support building on an older system with a newer SDK, as in building on 10.15 with an 11 SDK. I am sure there have been problems with trying to do this in the past for some releases. It *may* work but there are no guarantees. If you want to build on an older system you should use the SDK for that system even if a newer version of Xcode / Command Line Tools is released that provides the newer SDK. That said, I have no objection to trying to fix this issue but I think we should avoid claiming to support such configurations and I don't see this issue as needing to make a new release. I am willing to be convinced otherwise :)