Wont let me update to catalina
I have a late 2014 iMac running iOS Mojave and got the email suggesting to upgrade to Catalina
Its not present in my software update (under system preferences) and have also tried going through App store but get the message that software is up to date(1st screenshot) and no download available (2nd screenshot) when I hit GET. Have checked all the support pages and this iMac should definitely be able to run it. No problems with my 2015 MacBook which updated easily and is running fine.
Any suggestions?
iMac with Retina 5K display, macOS 10.14