A Left 4 Dead 2 update has been released. The update will automatically be applied when you restart your Steam client.

Changelog:

1. New mutation: Four Swordsmen of the Apocalypse

Addon Changes:

1. By default in single player and co-op game modes custom content will eclipse game content.
2. Add-on campaign’s custom content now loads first to avoid conflicts.
3. In competitive modes add-on loading is a server option.
4. Fixed an exploit that allowed people to modify materials on pure servers.
5. Default consistency checks now include pak01_dir.vpk. Add-on authors should not hack the pak01_dir.vpk directly but instead include content in a VPK.

Server changes:

1. The “whitelist.cfg” file located in the “steamapps\common\left 4 dead 2\left4dead2″ directory is now functional. Instructions on how to use this file are located in the file itself. Basically this allows the server operators to decide what files need consistency checks.