Currently Abandoned Very unlikely to find in use
Abandoned still in use
Windows 7 was used to transition people off the popular Windows XP Platform And get people out of the less popular Vista Platform
Windows 8 was a crap release which made the interface look like a phone, this required 8.1 to “fix the crap”. Both were interim releases for version 10
This brings us to Windows 10. This version appears to be stable and you should encourage people still using 8 to upgrade