Changing from OS High Sierra to latest OS
The OS version I have on my Mac is High Sierra. How do I update to latest version?
iMac 21.5″, macOS 10.13
Back up your data, check your applications for compatibility, and if your iMac model is recent enough, click on Mojave, Catalina, Big Sur, or Monterey. It needs to be at least a 2012 one to run any of them.
Catalina and newer won't run 32-bit software; download and use Go64 to scan for it. To check other programs, click here and look them up.
(214112)