Valve Release Left 4 Dead Update

Valve's also updated the PC version of Left 4 Dead which will be updated when you next log into the Steam client. The update includes:

• Fixed sv_search_key appearing in server browser
• Fixed issue where changing the sv_search_key did not update the master correctly
• Fixed master server issue with Linux fork mode that affected availability of Valve dedicated servers
• Tank melee attack can now hit multiple Survivors in one swing
• Missed from the previous list changes: Fixed achievements to match stats. Past achievements not previously awarded will be shown in the game UI

Source: Official