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:

• Added the Summer Appetizer Crate to the drop list and added the Summer Appetizer Key to the Mann Co. Store
  
• Fixed a server crash caused by multiple Spies sapping a building at the same time
  
• Fixed a case where a Medic deploying Kritzkrieg on a Spy would sometimes result in permanent crit boost