Big Sur - Update not found.

Does the computer Qualify for the UpGrade to Big Sur> Check Here

I am having the same issue (running 10.15.7) - every time I check for the update I get the message "Update not found The requested version of macOS is not available". I have restarted, checked via the app store; tried "About this Mac" > "Software update", but get the same message.

That is a very good question - I only purchased the iMac 5 or so years ago so had assumed it would still be eligible for the update due to its relatively young age. However - I've just checked the model (see below) are you are spot on - it is indeed not eligible... might be time for a new iMac methinks! Thank you for your help with this!