Yesterday I upgraded an Ignition server from 7.9.20 to 8.1.18 and ran into a bit of a headache with an existing database User Source. It looks like newer versions of Ignition require a “badge” column in the “*_users” table. It took a little while to figure out why the User Source wasn’t showing users. Poked around all over with no luck but then finally got a helpful error when I tried adding a new user and it complained about the badge column. Once I manually added the badge column to the “*_users” table, everything was happy.
There is a good probability this is due to my order of ops. Before running the upgrade, I (unintentionally… 
) isolated the Ignition server from the database so maybe it would have auto added the column since I had the User Source set to Automatic mode? Either way, it might be worth including a note on the additional badge column in the upgrade guide if it isn’t already there (I wouldn’t be surprised if I missed it).
Edit: I just realized that this error could have been present prior to the upgrade to 8.1. This was a test machine and I installed a fresh Ignition 7.9.20 instance but the gateway backup I restored was 7.9.3. I then immediately upgraded to 8.1.18 without checking functionality on 7.9.20. So I’m guessing that since no one else has mentioned this issue with 8.1 yet, then the issue was likely on the upgrade from 7.9.3 to 7.9.20…