An optional update (client bug fixes) is now available for Team Fortress 2. The changes include:

Engine
- Fixed a crash related to model caches.
- Fixed a crash related to empty proxy files.
- Fixed a rare crash involving corrupted voice-comm playback.

Team Fortress 2
- Fixed some issues with the community submitted tips.
- Fixed a case where servers could get stuck in an infinite loop while spawning bots.
- Made the training HUD code more robust, so it doesn't crash if the client has modified HUD resource files.
- Fixed a potential crash in the HUD during startup.
- Fixed a level change crash related to Bot navigation meshes.
- Disabled quickswitch UI in training to reduce confusion.
- The Demoman's battleaxe now sounds like a sword.

Missed a note from yesterday:
- The Eyelander now collects the heads inside Eyelanders of Demomen it decapitates.