What is best apple OS for mid 2011 iMac?
I still have Lion on my mid 2011 iMac, 27 inch. What OS can I safely upgrade to?
iMac (27-inch Mid 2011), Mac OS X (10.7.5)
Since you have not done upgrades since having Lion,
the only version available to you from the MacApp Store
would be the latest, macOS Sierra.
Getting any other version would require getting it from some
"other source" which would be highly suspect to all manner
of nasties.
