[multiplayer] Version Mismatch with host

So my friend and I are completely patched up, and when we try to join eachother's game over internet and over direct connect, the game tells us

version mismatch - critical game files do not match hosts

What could that mean? We have every patch that we know of, and our version numbers match.

Appreciate the help, cheers.

Perhaps one of you installed some mods improperly?

Perhaps you should clear the cache?

You could try to back up your assets folder and copy the folder of your friend to your computer?

As a last resort, uninstall (and manually delete all civ folders) and reinstall/repatch on both computers.