> I guess earlier versions of Windows stopped being Windows once version 8.1 was released.
Well, yeah. We're (presumably) talking about software architecture choices here. Are you telling me you'd purposefully build a new system on top of an old version of Windows, and specifically on old features that have since been deprecated+removed? If not, then it doesn't matter what old Windows does; "Windows is not POSIX-compliant" is the fact that you are making a choice based upon when you design a system right now.
POSIX compliance (which probably only serves as a checkbox for some arcane procurement guideline) is only relevant in niche markets. You are trying to apply a general software design thought process which unfortunately doesn't work there. People still ship WinCE and '95 software. Software targeting old UNIX systems is still being written today.
BTW, I can purchase a copy of windows 8 today (which is going to be supported by Microsoft till 2023) that is POSIX compliant. So the argument is moot anyway.
Well, yeah. We're (presumably) talking about software architecture choices here. Are you telling me you'd purposefully build a new system on top of an old version of Windows, and specifically on old features that have since been deprecated+removed? If not, then it doesn't matter what old Windows does; "Windows is not POSIX-compliant" is the fact that you are making a choice based upon when you design a system right now.