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:

• The Invasion Community Update has arrived!
  • Check out the blog post for more information
• Fixed a problem with the Steam Overlay for Mac clients
• Fixed a regression with weapon hit sounds
  • Hit sounds no longer clip each other
  • Min and max pitch values reverted to what they were prior to the October 1st update
  • Note: the Advanced Options default slider position is 100, which is normal (0) pitch
• Fixed an issue with the Festive Revolver not drawing correctly
• Fixed an exploit in Mann vs. Machine related to infinite credits
• Fixed an exploit related to The Dalokohs Bar
• Throwables (Jarate, Mad Milk, Flying Guillotine) will now pass through friendly targets at close range. This is the same behavior as rockets and grenades.
• The Powerhouse and Concealed Killer Weapons Cases have been added to the weekly drop list for Gun Mettle Campaign Coin owners