VALVE SURE DOES LOVE UPDATES! August 28, 2013 - Team Fortress 2 Update Released
An update to Team Fortress 2 has been released. The update will be applied automatically when you restart Team Fortress 2. The major changes include:
Fixed the Linux dedicated server failing to run on older Linux versions
Fixed the HUD 3D Character causing other HUD items to sometimes disappear
Fixed a client HUD crash when Spies disguise as a class that has a non-active weapon like the Chargin' Targe
Fixed an outdated tip for the Quick-Fix
Fixed a shadow bug for the Warrior's Spirit
http://www.steampowered.com/platform/update_history/index.php?id=440...that being said, the servers probably auto updated and nobody could join because they were too lazy to update.