That wouldn’t be compatibility mode, that would be shipping an entire copy of an older OS version. From a quick search, it looks like compatibility mode entail

That wouldn’t be compatibility mode, that would be shipping an entire copy of an older OS version. From a quick search, it looks like compatibility mode entails interposing a library between the app and the OS libraries, and the library emulates the behavior of an older OS. It’s not automated, each compatibility fix is crafted to work around a specific issue. In theory a fix could be made for this issue, but they’d have to find it and debug it first.