The "every second version" rule may be a meme, but it does not reflect the actual release order of Windows, nor properly count the NT series. It only really applies to sentiment surrounding Windows 98, ME, XP, Vista, 7, 8, 10, and 11. But that leaves out Windows 95, most versions of Windows NT, and Windows 2000.
I find this to be a mostly valid assumption, and 8.1 shouldn't be counted separately from 8 just as Vista SP2 should be counted any differently from Vista (Vista was mostly fine after companies fixed their drivers and Microsoft toned things down a bit. 7 just drove that home and put some necessary distance between itself and Vista).
> Also 95/98/me were a different line from NT/2000.