Updates to Left 4 Dead 2 have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

Left 4 Dead 2
  • New mutation: Room For One.
  • Improved SurvivorBots ability to support players who stop moving to fight infected.
  • Improved SurvivorBots ability to support players in tight spaces.

Match Making Changes
  • Server searches for Official Dedicated servers no longer automatically fall back to Best Available. Lobby leaders will be given the option.
  • Lobby leaders can select "Steam Group Server" as a server option. This will allow them to select individual servers.