Upgrading OS, which one works best with Mail?
I've finally able to upgrade my iMac OS. It is currently 10.9.5. I have multiple problems with Mail which, I'm told, will be resolved when i upgrade my OS. Are there higher systems to avoid due to problems with Mail? I'm real leery of upgrading because I don't know which programs I use a lot will have trouble, but the program I'm most concerned about is Mac Mail.
My iMac is Mid 2010, but that isn't an option for the device listed below.
iMac Line (2012 and Later)