Left 4 Dead 2 update!

Valve has posted a new update to Left 4 Dead 2 and the Left 4 Dead 2 SDK.

Release notes:

Gameplay
Now ghost PZ's can never be staggered
Enabled PZ bots
PZ bots use their more aggressive survival mode behavior in versus and scavenge
Enabled finale manual spawn by default
Fixed human PZ players not getting counted when they were dead, allowing extra PZ bots to spawn
Reduced effectiveness of melee weapons against the Tank ( 5% of max health, from 10% )
Fixeda case where a player who dies, then is rescued from a rescue closet,and then is revived from a ledge hang receives the secondary weaponthat he lost when he was initially killed
Improved SurvivorBot AI in cases where the bots refused to shoot through their teammates and became non-responsive
Fixed issue with witch sometimes taking on uncommon common properties
Fix for cheaters quitting before the vote to kick them would succeed and avoiding ban on server
VAC banned users can now play L4D2 single-player, commentary mode and credits

Map Fixes
Dark Carnival Fair Ground: added env_player_blocker to keep special infected from getting stuck
Dark Carnival Fair Ground: added navigation area that was missing
Dark Carnival Fair Ground: Disconnected drops that were blocked by the top of a fence
Swamp Fever Plank Country: Deleted 2 nav areas that connected between tree trunks you can't pass through
Swamp Fever Shanty Town: Redrew ladder thinner so special infected could climb up to the roof
The Parish Waterfront: Fixed various navigation areas
Mall: Tuned spawning for difficulty

SDK Content
Added missing nature/blend tooltextures added
Added missing cs models/textures
Added missing acunit01 model/texture
Added missing ammo_can_02 model/texture
Added missing patio_chair model/texture

Source: http://store.steampowered.com/news/3408/