I've updated all of the COD4 servers to the 1.4 patch. You'll need to patch your game to this revision to play on the {MOB} COD4 servers.
Here's what the 1.4 patch does for players:
Changes
● Adds a "Winter Crash" map, a holiday version of Multiplayer map "Crash"
● Improvements to the server browser
● Fixed some rare bullet accuracy issues for all weapons
The name of the patch file is CoD4MW-1.4-PatchSetup.exe and you can download it from our files section here http://8.9.4.75/other/CoD4MW-1.4-PatchSetup.exe