Updates to Left 4 Dead 2 have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

General:
-Fixed missing steam avatars in transition panel.
-Witches on fire will now continue to attack instead of sometimes flailing around aimlessly.
-When infected players slash at a jockeyed survivor, all damage will be applied to the survivor and not the jockey.
-Added some missing music files for the L4D1 campaigns.

Crash Course 1:
-Rescue closet doors that are blocked in versus are now inaccessible to both teams.
-Fixed the area portals near the howitzer event. Players should now be able to see through the infected-broken holes in the walls properly.

Crash Course 2:
-Rescue closet doors that are blocked in versus are now inaccessible to both teams.
-Removed a bad item cluster in the finale which was causing too many items to spawn.

Dead Air 3:
-Fixed an AI bot pathing issue with climbing the fence leading into the construction yard.
-Removed the ability to climb an electric box prop near the barricade in the construction yard. It should no longer be possible to skip the barricade event.
-Added an infected ladder to some pipes on the far side of the barricade to create a route for player infected on that side to easily enter the construction yard.

Blood Harvest 4:
-Widened the gap in the railing on the final bridge.
-Falling off the cliff or the final bridge is now fatal to both teams.

Blood Harvest 5:
-Fixed a potential bug for low-end machines where certain walls and textures near the starting safe room would vanish in certain views.


Cold Stream 1:
-There is now only a single hunting rifle in the cabin after the rope bridge.

Cold Stream 2:
-Moved the magnum near the start of the map, nearer to the other tier 2 weapons.
-Tier 2 weapons near the start of the map are no longer single-spawn.
-Adjusted cars and road props to reduce the chances of players getting caught on geometry.
-New infected ladders added.
-Added a weapon spawn in the tent on the barrel explosion bridge.
-Fixed an exploit that allowed survivors to climb the tent on the bridge to skip the barrel explosion event.
-Added an M60 under the barrel explosion bridge.
-There are now slightly more infected coming at slightly faster intervals during the end-level onslaught.
-Fixed a bug where players and infected could get caught in the geometry along the walls in the tunnel leading to the stairwell during the onslaught.
-Several minor visual tweaks and bug fixes for performance throughout the map.
-Added wrong-way signs to indicate when infected players have reached the end of the playable parts of the map.
-Fixed several spots where players and AI could get stuck.

Cold Stream 3:
-Added a new, much more obvious path across the tanker explosion gap.
-Tweaked the wooden catwalk area following the tanker explosion to make it easier for survivor and infected AI, as well as infected players, to navigate.
-The water now has a new texture effect which will work on low end machines.

Cold Stream 4:
-Fixed a melee weapon that liked to spawn inside of a table near the start of the map.
-Fixed a case where AI infected would sometimes get stuck trying to mount the drain to climb up toward the start of the map.
-Consolidated items in the tank fight area at the halfway point.
-Altered tank fight area in the stream so that AI tanks don’t spawn in nearly useless/sitting duck locations.
-Removed one of the triage tents and replaced it with an open trash/storage area.
-Added a pair new routes up the final tower for infected players to reduce AI common infected collision and pathing issues, and to give infected players more strategic options.
-Several prop adjustments for players using low-end settings.
-Added wrong-way signs to indicate when infected players have reached the end of the playable parts of the map.