> What would it even be? 128 bit? Back to x86? Notarization++? Metal 4 incompatible with Metal 1?
Sure, I can think of lots of things. Every macOS update when I worked in this space broke something that we had to go fix. Code signature requirements change a bit in almost every release, not hard to imagine a 10-year-old game finally running afoul of some new requirement. I can easily see them removing old, unmaintained APIs. OpenGL is actively unmaintained and I would guess a massive attack vector, not hard to see that going away. Have you ever seen their controller force feedback APIs? Lol, they're so bad, it's a miracle they haven't removed those already.
You see, the existence of that "almost" is already less confidence than developers have on every game console as well as Linux and Windows.