While checking through ‘new releases available’ emails, I found one of my sites hasn’t been migrated to D9 yet. This was a surprise as I was absolutely positive this one had already been migrated, if not already at the very least fully prepared and ready.
However after examining the Upgrade Status report, there are several errors, none of which I understand. Could you help, please?
I understand your confusion, but no need to worry. Once your website is updated to Drupal 9, it will automatically pull the newest release which includes a much newer version of the CERN Theme. In other words: There is no need to try and fix any of these as they have already been resolved in newer versions which will automatically be applied once updated.