At least for Wotlk.
I run 3.10.6 and i keep getting the message in chat that a newer version exists whenever someone logs in. The player in question is running an older version, actually, 3.9.x
Could it be possible to fix this QoL stepdown? :(

Okay, on Git I've modified how the new version cache is generated to account for numbers greater than 10 for the build number.

This will be in the next release.

Yell at that person, but that's weird.