The TF2 update Valve has been mentioning in their blog is now out, and it's a big one!

Given the huge swath of changes in this update, some of our servers may be knocked out of commission for a bit.

Here are the changes:

General:

- Added over 60 Gold Star community-submitted Workshop items
- Summer Claim Checks can now be redeemed for Summer Coolers
- Summer Cooler Keys are now available in the Mann Co. Store
- Map Stamps and Strange Filters for the new community maps cp_standin and cp_process are now available in the Mann Co. Store

- Reduced intensity of Bleed and Jarate screen effects under DX8
- Added text search functionality to the backpack and the store
- Added tf_hud_show_servertimelimit to display the server's per-map time limit on the in-game HUD
- In MvM, if all team members unready, the pre-round countdown will stop
- In MvM, when robots are killed by sniper headshots or explosive headshot upgrade, they will drop 'red' money that will automatically be collected when it would otherwise dissolve
- Fixed a bug with the Unusual Adjustment Slider that would cause changes not to take effect
- Double-clicking a crate will now take you to the appropriate key in the store
- By default, items with non-standard qualities (ie., strange, unusual) will not be selectable as craft ingredient. The ingredient selection UI has a checkbox to disable this feature and allow selection.
- Unusuals and Stranges no longer stack in loadout equip pages
- Fixed a bug that would sometimes cause incorrect Steam Community Market prices to be shown on item tooltips when using non-USD currencies
- Fixed a bug that would cause the popular items page in the store to not always update correctly
- Fixed a bug where disguised red spies spawned a blue heal particle when touching healthkits
- Fixed a bug where certain projectiles and Engineer building gibs could cause doors to become stuck
- Fixed a bug where crouch animations would not properly play while in humiliation state
- Fixed a bug where full ÃœberCharge effects would always show on the client if a player was killed with full ÃœberCharge
- Fixed a bug that allowed custom item names/descriptions containing HTML to sometimes change the appearance of items in Steam Community
- Fixed level 3 dispensers missing geometry
- Fixed level 2 dispensers appearing identical to level 1 dispensers at certain LODs
- Fixed the Marked-For-Death effect showing over the head of disguised or stealthed players
- Fixed suicide deathnotices showing the dead player's last deployed weapon instead of the skull and crossbones
- Fixed characters in the loadout page sometimes appearing as if they were cloaked
- Weapon attributes will now show in the same order in-game and in Steam Community
- Support for the ITFItems/GetPlayerItems and ITFItems/GetSchema WebAPIs have been removed

Maps:

- Added cp_standin and cp_process
- Renamed mvm_coaltown_event to mvm_ghost_town to fix a problem with voting for challenges in MvM when on Coal Town

- cp_badlands
- Fixed jumps being ruined by small rock ledge near spiral
- Fixed prop collisions
- Fixed clip smoothing
- cp_dustbowl
- Fixed players building in Blu's first spawn
- Fixed players shooting through rocks in stage 2
- Fixed collision in tunnels in stage 2
- Fixed textures not displaying properly in Pyrovision
- Fixed lighting on cliff faces
- Fixed skybox error in stage 3.
- Fixed players getting killed through the ceiling under stage 2 cap 1
- Adjusted ceiling height in stage 3 tunnel for better clearance
- Cleaned up prop collision
- cp_egypt
- Fixed clip brush exploits
- Players can no longer build on top of arches and high ledges
- cp_gorge
- Players can no longer build in Blu's first spawn room
- Changed scale of water texture

In fact the notes are so large, they don't fit in this group announcement!
Read the rest here: http://www.teamfortress.com/post.php?id=11070