Upgrade OS X Lion 10.7.5 to High Sierra
I have iMac mid 2011 running OS X Lion 10.7.5. I've tried to download High Sierra, but it says I have to have OS X Lion 10.8 to upgrade. How can I upgrade? My outdated OS is causing a number of issues (iTunes won't let me back up my iPhone and other apps can't be updated). Can I update to 10.8 and then get High Sierra?
iMac, Mac OS X (10.7.5), Upgraded RAM