Which, for an open source OS, is honestly not that unreasonable, even if it is frustrating for cases where you have old binaries with no source.

For these old binaries, there probably wouldn't even need to be any source-fixing; a straight recompile would probably be enough.

(Ironically, another poster downthread points out old UE1 apps often don't run on Windows, either, without binary modification, so it's not like MS is squeaky-clean there either.)

Linux (mostly) doesn't have a problem with binary backwards compatibility. It's everything around Linux that is generally the problem.

Linus is adamant about new versions of the kernel not breaking compatibility with userspace. The problem is with the rest of the system.