> and license activation isn't performance-critical code.
No, but DRM is pretty likely to require your OS to remain exactly bug-compatible with older versions. After all, the entire point is for it to cause trouble if it detects unexpected changes in system configuration or behavior, even if those changes are within the scope allowed by loose API definitions or undefined/unspecified behavior. E.g. it's pretty much expected that when an OS tightens security restrictions, it'll break a lot of DRM and video game anti-cheat systems. Inserting a new compatibility shim is also likely to be mistaken by those systems as a circumvention tool.
Well, that assumes the DRM is stringent. I don't think Adobe's ever was, it was certainly cracked easily enough. CS6's activation system has also survived _many_ macOS updates, up until this moment when Apple outright ripped out 32 bit. Maybe that's because Apple was purposefully maintaining compatibility with CS6 explicitly, but given how they operate, I kind of doubt it.
No, but DRM is pretty likely to require your OS to remain exactly bug-compatible with older versions. After all, the entire point is for it to cause trouble if it detects unexpected changes in system configuration or behavior, even if those changes are within the scope allowed by loose API definitions or undefined/unspecified behavior. E.g. it's pretty much expected that when an OS tightens security restrictions, it'll break a lot of DRM and video game anti-cheat systems. Inserting a new compatibility shim is also likely to be mistaken by those systems as a circumvention tool.