I have versions 1.2.0.1, but most everyone else has 1.2.0.2
There are no pending updates on steam, and I can’t figure out how to get my version up to date? Is there some issue due to having used mods? Or is there some other technical issue that I’m not aware of? Thanks in advance!
If you’re using a mod or tool then they need to be updated for the latest version of the game as well.
You could also try verifying the game files.
You can try open Documents\My Games\Grim Dawn\Settings\options.txt and set skipCompatibilityChecks option true.
restart steam client, sometimes client need a kick to register game update is out
how would that work/matter?; wouldn’t the game just crash/refuse to load if internal data isn’t the same ? 
I did not conduct global tests, but I think it may cause desync.
I played mod with small database difference and haven’t seen any issues. And once I could join to dev build right on stream.