The 1.15 patch is also a must for online gaming:
Improved performance
Improved multiplayer stability
Added update notification button on the main screen
Improved computer players' behavior (AI)
The editor allows selection of computer controlled players
Fixed problems with dual monior configurations
Ghouls no longer carry 20 food when summoned
The heroes in adventure mode do not speak as often as before
The difficulty of the TRATUA adventure mission has been corrected
Various additional small fixes and updates
Note: This patch requires v1.10 or newer.