Thanks Tim, that link was super useful.  In my case, these errors were logged only once on each affected MID server when we applied the last round of patches 17 days ago.  All MID servers had patched successfully and were on the same build when work completed.  I guess these errors resolved on their own and should have been automatically cleared by the pre-upgrade checker.

Awesome!

Thanks for the update, Andy.
    - Tim.

Can the MID server be upgraded if air gaped? Like if certain install files are in the directory once the APP servers are upgraded to a new city version

In theory it's supposed to work but I have only manually uninstalled and reinstalled a new version.

Which is a pain. But placing the files in agent/package/incoming does not work for me either