Updates to Team Fortress 2, Day of Defeat: Source and Half-Life 2: Deathmatch have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:
Source Engine Changes (TF2, DoD:S, HL2:DM)

• Fixed HTTP downloads on Mac not sending an HTTP referer

Team Fortress 2

• Updated materials/models for the Champ Stamp, King of Scotland Cape, Stovepipe Sniper Shako, and Freedom Staff
• Fixed a server crash that could occur if a Spy was disguised holding the Gunslinger
• Fixed the Lacking Moral Fiber Mask being tagged as a misc item instead of a hat
• Fixed the Gunslinger not accepting "Sappers Removed" strange parts
• Overhealed players that are bleeding or on fire can now pickup healthkits to remove these conditions
• Added tf_dingalingaling_repeat_delay (default 0) which limits how often the dingalingaling sound can play
• Removed outdated tip about the Spy's Enforcer
• Updated the localization files
• Vote system
  • Allow kicking of connected players that haven't joined a team in Mann vs. Machine
  • Added sv_vote_issue_kick_spectators_mvm (default 0) which allows players to kick anyone that isn't team invaders, as long as they've passed the sv_vote_issue_kick_min_connect_time_mvm timer, if enabled
• Mann vs. Machine
  • Added two new tours of duty, each with new unique loot:
    • Operation Oil Spill, with 6 new intermediate skill missions
    • Operation Gear Grinder, with 3 new expert skill missions
  • If a player connects to a MvM game through matchmaking and loses their connection, their spot will be held for a brief duration and they will be given a chance to reconnect
  • After victory on a Mann Up server, the players will be put into a lobby together.
  • Improved matchmaking searching status screen
• Mann vs. Machine balance changes:
  • Explosive Headshots
    • damage is now 150 regardless of upgrade level
    • damage is done in one tick instead of the previous six
    • added a slowing effect based on upgrade level (50%-80% slow, 2-4 second duration)
    • radius still scales with upgrade level (unchanged)
  • Marked For Death duration reduced to 7 seconds from 15 seconds when the target is a giant robot
  • Reduced the "effect bar recharge rate increased" upgrade from 20% increments with an 80% cap to 15% increments with a 60% cap