[TonyTrapp]

C++ the language also has pretty strong backwards compatibility. It's also trivial to install a new Clang version on most systems. But it certain spaces that's not what matters. Maybe you are only allowed to use That One Certified Compiler from 15 years ago and getting a certification for a newer compiler is not feasible. Or maybe you're on a system where the C++ standard library is part of the system and so you cannot use newer language features because that would require raising the minimum required OS version (I remember that some parts of the C++ standard library are not available if you compile for older macOS versions, for example).