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:

Happy Smissmas 2017!
• All players who play TF2 during the event will receive a Stuffed Stocking as a gift! Stockings contain goodies for good little Mercenaries.
  • Event runs through January 10th, 2018
• Added the Winter 2017 War Paint Case
  • Contains 15 new community-contributed War Paints
    
  • Randomly dropped for players who have activated a Jungle Inferno Campaign Pass
• Added the Winter 2017 Cosmetic Case
  • Contains 20 new community-contributed items
    
  • The Festivizer can be found as a bonus drop when opening the case
• Added 6 new community-contributed taunts to the Mann Co. Store
  • Taunt: The Skating Scorcher
    
  • Taunt: The Bunnyhopper
    
  • Taunt: Runner's Rhythm
    
  • Taunt: Luxury Lounge
    
  • Taunt: Surgeon's Squeezebox
    
  • Taunt: The Trackman's Touchdown
• Expanded the list of weapons that can be Festivized!
  • Ubersaw, Dragon's Fury, Amputator, Air Strike, Back Scratcher, Scotsman's Skullcutter, Bazaar Bargain, Black Box, Claidheamh Mòr, Crusader's Crossbow, Degreaser, Loose Cannon, Persian Persuader, Detonator, Brass Beast, Holy Mackerel, Loch-n-Load, Powerjack, Iron Bomber, Reserve Shooter, Disciplinary Action, Family Business, Shahanshah, Scorch Shot, Shortstop, Soda Popper, Rescue Ranger, Tomislav, Panic Attack, Winger
• Mann Co. Store winter sale!
  
General
• War Paints can now be used for Mann Co. Trade-Ups
  
• Fixed a rendering issue with the Misty Skull unusual effect
  
• Fixed a case where it was possible to use the Thermal Thruster twice in one launch
  
• Fixed the inspect animation for the Shortstop
  
• Fixed the Festive Sandvich not showing the bite mark when eaten
  
• Increased the maximum number of backpack slots to 3000 (from 2500)
  
• Added the UGC Highlander Season 21, Highlander Season 22, Highlander Season 23, 6v6 Season 23, 6v6 Season 24, 6v6 Season 25, 4v4 Season 10, 4v4 Season 11, and 4v4 Season 12 tournament medals
  
• Added Ready Steady Pan Season 3 tournament medals
  
• Updated cp_mercenarypark
  • Added a forward spawn for BLU when attacking the final control point
    
  • Added a connecting stairwell to the mid-structure of the final control point
    
  • Fixed area portal rendering issues between the first and second control points
• Updated pd_watergate
  • Respawn times of the teams will change dynamically based on the difference in scores. This should help balance any extreme differences in the team skills/scores.
    • <50% difference in scores: 8s for leading team, 4s for trailing
      
    • >50% difference in scores: 12s for leading team, 0s for trailing
      
    • Equal scores: 6s for each team
  • Relocated the player beer pickup counter on the HUD to the lower left, but made it slightly larger
    
  • Updated the soundscape to have more alien-y sounds in the main areas
    
  • Adjusted detail in the center and spawn rooms
    
  • Adjusted clipping around the map