I have an iMac 21.5 inch Late 2009 and am running macOS Sierra v. 10.12.6 - how do I upgrade or am I maxed out?
I have an iMac 21.5 inch Late 2009 and am running macOS Sierra v. 10.12.6 - can I upgrade?
iMac, macOS 10.12
Check out How to upgrade to macOS High Sierra to see if it qualifies. This would be as far as you can take it.