Gotta love versions. Giant headache. Programmatically, it's NO FUN to try to figure out whether version 7.2 of a piece of software is newer or older than version 7.12 is. You can't compare them mathematically, and the system provides no way to convert to a flat integer, so everyone has to make up their own way to compare, and some are bound to get broken on weird cases. (like version 7.05 or 7.2.B o 7.2B5 etc) Adobe likes to pull those stunts.
And then we note that there's no Windows 9.... you'll find a few explanations floating around for that, but it came down to programming.
The common (possibly sanctioned/recommended?) way to tell if a computer was running a really old version of windows, specifically 95 or 98, was simply to check the first digit for "9". If it sees a 9, nope, that's WAY too old for the installer to run. It apparently broke so many installers (that ran fine on windows 7 and 8) that they had to skip 9.
They SAY officially that they wanted to go with something that seemed more modern, probably in comparison to mac os 10, but the actual reason came down to the quirky fact that "windows 9" would break a lot of software, and a great number of installers available at the time. And even APPLE does that crap with their build numbers for the OS. See the 17G65
MACINBOX:~ root $ cat /System/Library/CoreServices/SystemVersion.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<string>1983-2018 Apple Inc.</string>
<string>Mac OS X</string>