A memory leak in Apple's Network Extension framework

I wish there was an independent unit test suite for operating systems and other proprietary software.

The suite would run the most-used apps and utilities against updates and report regressions.

So for example, the vast majority of apps on my Mac can't run, because they were written for early versions of OS X and OS 9, even all the way back to System 7 when apps were expected to still run on 4/5/6. The suite would reveal that Apple has a track record of de-prioritizing backwards compatibility or backporting bug fixes to previous OS versions.

Edit: integration test suite

Eh, I agree in a sense, but I'm also ok without the same level of backwards compatibility that Windows is beleaguered by. Every new version of Windows is little more than a thin veneer of whatever they think is a popular choice for UI design that year, and with that comes a clumsy amalgamation of hugely varying settings dialogs, the classic registry, all the goop. Meanwhile on macos, I don't expect very complex software to maintain perfect compatibility, but I can reasonably expect most of the stuff I use to carry forward 5+ years. Parallels and Omnifocus were the exceptions, but 1password from 2012 is still kicking, Data Rescue 3 somehow still works, I'm sure even Adobe CS6 would even though it's from the Carbon era.

Just as well, although I loathe some of the choices Apple's made over the years, such as it's own Settings app, the overall UI would be pretty recognizable if me from 20 years ago found a time machine (pun intended). I recently bought a new mac, and it occurred to me that it feels basically like the E-Mac I used in middle school all those years ago, albeit with the occasional annoyance I wouldn't have been aware of then.

CS6 is after the Carbon2Cocoa effort, IIRC. No 32bit apps run on modern macOS and Carbon was infamously 32bit only.