I'm rocking an HP Mini with Windows 7 Starter and it's good to go.
Here's something to remember, Windows 10 has the dreaded automatic Update built into the OS. Meaning, even if you turn it off, or "schedule" when it can check for updates, it still does it automatically in the back ground as soon as it get's connected to the net. You literally can't disable that function. With that being said, here at my job, I constantly see Windows Updates discreetly and sneakily make configuration changes on our computers with Windows 10. This typically happens with Cumulative Updates and Security Updates. Win 7 is not like this. If you disable Automatic Updates, it stays off. Which is the main reason why I went with Win 7.
And one last tid bit. Microsoft will end "Extended Support" for Windows 7 on Jan 14th 2020. Which means, they won't be doing updates or giving support for Win 7 OS after that. Even though we've recently seen them do some fire fighting with virus issues that affected XP.
Anywho, I'd recommend pretty much any version of Win 7 and XP being GTG as well.
-Patrick-