Multiplayer version issues

Me and a friend were trying to play Eastern Front, with him just having downloaded the game. When we tried to join each other's games the versions were different though.

Thing is, both of us have the latest updates for both vanilla CoH and Eastern Front. I'm running from Tales of Valor and he's running from original CoH (with both expansions). Could that be the issue?

Thanks in advance!

Both installed the five updates for EF(1.20~1.232)?

Does someone use steam CoH?