iMac mid 2011 upgrade to High Sierra 13 or to Mojave?
Is there a fix to upgrade an iMac mid 2011 to High Sierra 13 or to Mojave?
Download macOS High Sierra 10.13.6 Combo Update
https://support.apple.com/kb/DL1970?locale=en_US
You would need a 2012 or later iMac to get Mojave, beginning in 2012 the GPUs supported Metal which Mojave requires in order to run. No, you cannot upgrade your GPU and no there is no other method of running Mojave on your 2011.
