Updates (Left 4 Dead 2)

NOTE: All Servers update to the latest versions every time a new update is released.

The following is a history of updates applied to Left 4 Dead 2. Updates to the PC versions (Windows, OS X, or Linux) will be downloaded automatically when available and not playing a game, or after restarting your Steam client. You will be prompted to download updates for the Xbox 360 version when the game is started. The last update to the Xbox 360 version was on August 3, 2012. Updates to the PC version are listed below in reverse chronological order:

November 1, 2018

 * Fixed potential buffer overflow in closed captions. Reported via HackerOne.
 * Dev command 'director_log_scavenge_items' can only be executed by the server. Reported via HackerOne.
 * Protect against invalid map displacement data.
 * Fixed official servers allowing clients to load custom content in competitive modes.

October 31, 2018

 * Fixed a potential buffer overflow in closed captions. Reported via HackerOne.

August 22, 2018

 * Fixed some potential remote code execution exploits. Reported via HackerOne.

August 21, 2018

 * Fixed some potential remote code execution exploits. Reported via HackerOne.
 * Updates to caption localization.

June 6, 2018

 * Fixed a potential remote code execution exploit.

November 30, 2017

 * Security and exploit fixes.

August 1, 2017

 * Fixed a new bug causing some items to not transition between levels.
 * Added missing model precaches to Left 4 Dead 1 Mutation mode.

July 27, 2017

 * Prevent a crash if a material overflows the index buffer.
 * Zombie population fixes for Left 4 Dead 1 Mutation modes.
 * Fixed some material properties on Left 4 Dead 1 common infected models.

July 17, 2017

 * Fixed a crash after failing to load a map.
 * Fixed a crash caused by missing materials.

February 21, 2017

 * Configuration files are no longer loaded from addon vpks. These configuration values were sometimes used for malicious purposes, and all changes remained in the user's local settings even after the addon was disabled or removed. When necessary, addon authors should inform users of any required configuration changes in the description on the workshop page.

January 25, 2017

 * Fixed a server lagging exploit.
 * Fixed some reported security exploits.
 * Fixed key bindings not displaying correctly when using the Xbox 360 controller.

New EMS scripting features:
 * Added a new interface for reading/writing entity network and data table fields from script. Use "script_help NetProp" for interface details.
 * New script function "TakeDamage( amount, type, attacker )".
 * New script function "GetNetworkIDString".
 * Added "timeofday" keyfield to the world entity.
 * Support auto_spawn of witch bride.

June 28, 2016

 * Fixed an issue on some MacBook Pro models that prevented the game from rendering correctly, resulting in a blank or white screen with game running in the background. This fix required a change to the minimum spec from MacOS 10.6.4 to MacOS 10.7 (Lion) or higher, which matches Steam's minimum spec.

June 3, 2016

 * Fixed multiple potential remote code execution exploits.


 * Speculative fix for Mac startup rendering issue.


 * Updated Steam API version.

May 4, 2016

 * Fixed two exploits that could allow remote code execution on clients and servers.


 * Disabled some debug tracking that was causing a crash.

February 18, 2016

 * Fixed an exploit where a player could call a vote that would pass immediately without input from the rest of the players.
 * Fixed an issue where sounds could start looping on Linux.
 * Fixed Steam Controller issues with spectating and MOTD.
 * Fixed a bug that could cause some servers to hang on shutdown, causing a temporary reduction in total server capacity after updates.
 * Fixed a remote code execution exploit.
 * Upgrade OSX SDK version.

February 2, 2016

 * Fixed two exploits that could allow remote code execution.
 * Fixed controller navigation of some lobby settings menus.

December 19, 2015

 * Added haptics support for Steam Controllers

December 17, 2015

 * Fixed Options menu cutting off Steam Cloud option.

December 10, 2015

 * Fixed some Steam Controller bugs
 * Added bindings for voting with the Steam Controller

November 11, 2015 (Authoring Tools)

 * Fixed Workshop Manager failing to launch.

November 10, 2015 (2.1.4.3)

 * Additional bindings and fixes for Steam Controller support.

November 6, 2015 (2.1.4.2)

 * Added native steam controller support.
 * Added support for surround sound on SteamOS.

October 14, 2015 (2.1.4.1)

 * Fixed an exploit that could shut down dedicated servers.
 * Fixed several buffer overflow exploits with networked files.
 * Fixed a series of exploits caused by invalid or malformed textures.

October 1, 2015 (2.1.4.0)

 * Fixed several security issues

February 6, 2015 (2.1.3.9)

 * Fixed a possible crash when a server goes into hibernation.
 * Fixed an occasional crash in the physics system when touching entities are deleted.
 * Fixed a crash in scripted_user_func command.
 * Fixed Survivor bots picking up weapons from a spawner that was already depleted.

January 29, 2015

 * Fixed Steam Cloud and VPK Association dialogs appearing behind the main menu and blocking all input.
 * Cheat-protected some console commands that could be used to lag servers.

January 23, 2015 (2.1.3.8)

 * Fixed an edge case where a Survivor that should have been incapacitated from taking damage would be killed instead, even though the Survivor wasn't on third strike.
 * Cheat-protected some sound mixer commands to prevent exploits.

November 21, 2014 (2.1.3.7)

 * Fixed low volume with some speaker configurations.

April 29, 2014 (2.1.3.6)

 * Fixed an exploit that could allow clients to transfer blacklisted files to and from the server.

January 8, 2014 (2.1.3.5)

 * Fixed several rare but persistent crashes:
 * Round restart in No Mercy map 1
 * Witch eye glow particle system
 * Chainsaw pose parameter update
 * Common Infected post data update
 * Scavenge mode scoreboard
 * Fixed text input not working correctly in Hammer model browser search field.

January 3, 2014

 * Fixed memory buffers not getting freed after downloading workshop items.
 * Fixed a vpk loading bug that could cause an out of memory error.

December 17, 2013 (2.1.3.4)

 * Fixed a file management bug that could cause some users to run out of memory when opening the Addons screen.
 * Removed SSE2 requirement that was added during the Linux port.
 * Fixed plugin handler reporting all commands as coming from the server, even when they came from the client.

November 7, 2013
Map exploit fixes:
 * Fixed chainsaw effects stuck on when a player dies
 * Split shared melee weapon sounds and script entries so they can be modded individually

The Parish 4 The Sacrifice 1 The Sacrifice 2 No Mercy 1 No Mercy 2 No Mercy 3 Cold Stream 1 Cold Stream 2
 * Restored player blocker near the parade float crescendo event after map restart
 * Blocked Survivors from an infected-only area near the safe room
 * Prevented Survivors from skipping the gravel pile crescendo event
 * Added truck headlight beams
 * Blocked Survivors from the roof of the bus stop
 * Prevented Survivors from skipping the generator event
 * Blocked the top of a subway car
 * Blocked a fence top after the generator event
 * Prevented Survivors from escaping the map
 * Blocked Survivor access to an invulnerable window ledge
 * Prevented Survivors from skipping the gas station lift crescendo event
 * Blocked Survivors from getting on the tower roof
 * Prevented Survivors from jumping over a truck near the barricade

October 23, 2013

 * [Linux] Fixed controller support
 * [Linux] Support for Chinese font rendering
 * [Linux] Fixed problems with incorrect mouse grabbing when joining a game
 * [OSX] Fixed problems with lerp calculations
 * Rolled back CEF version to see if it was the cause of vertex buffer errors

October 22, 2013 (Beta)
Map exploit fixes:
 * Fixed chainsaw effects stuck on when a player dies
 * Split shared melee weapon sounds and script entries so they can be modded individually
 * [Linux] Fixed controller support
 * [Linux] Support for Chinese font rendering
 * [Linux] Fixed problems with incorrect mouse grabbing when joining a game
 * [OSX] Fixed problems with lerp calculations

The Parish 4 The Sacrifice 1 The Sacrifice 2 No Mercy 1 No Mercy 2 No Mercy 3 Cold Stream 1 Cold Stream 2
 * Restored player blocker near the parade float crescendo event after map restart
 * Blocked Survivors from an infected-only area near the safe room
 * Prevented Survivors from skipping the gravel pile crescendo event
 * Added truck headlight beams
 * Blocked Survivors from the roof of the bus stop
 * Prevented Survivors from skipping the generator event
 * Blocked the top of a subway car
 * Blocked a fence top after the generator event
 * Prevented Survivors from escaping the map
 * Blocked Survivor access to an invulnerable window ledge
 * Prevented Survivors from skipping the gas station lift crescendo event
 * Blocked Survivors from getting on the tower roof
 * Prevented Survivors from jumping over a truck near the barricade

October 11, 2013

 * [Linux] Fixed crash when showing server MOTD.
 * [Linux] Implemented microphone support.
 * [Linux/OSX] Fixed occasional crash when playing with captions. Also fixed some captions not displaying at all.

October 4, 2013

 * Improved ability to debug client crashes

September 18, 2013
Mac / Linux
 * Fixed a buffer overrun which could cause a crash on start-up
 * Fixed an audio bug which could cause a crash on start-up

EMS
 * Allow scripts to write to sub-directories of the 'ems' folder
 * Script system will look for *_entities.txt files in /ems/maps as a fallback

August 16, 2013
Tweaks to add-on management:
 * Report conflicts between mission scripts in the Add-ons menu.
 * Fixed checked items getting unchecked after reporting a conflict.
 * Allow all add-ons to override base content at the main menu.
 * Allow content-only add-ons on non-vanilla dedicated servers.
 * Allow add-ons to override base mission and mode scripts on non-vanilla servers.

August 5, 2013
General:
 * Fixed loading screen showing placeholder text when playing mutations.
 * Fixed a bug that always allowed Special Infected to spawn when a mutation was active.
 * Fixed an out-of-range volume setting for one of Nick's lines.
 * Fixed missing Russian audio in The Passing
 * Fixed missing localized audio in No Mercy
 * Improved stability when using hybrid graphics on Bumblebee

Additions to EMS Scripting:
 * "ClearedWandererRespawnChance", percent chance (0-100) that cleared nav areas will get re-populated with wanderers.
 * "Convars.GetClientConvarValue( cvar name, entindex )"
 * "Convars.SetValue( cvar name, value )". Only server cvars can be set from script.
 * player.IsDying
 * player.IsOnFire
 * player.Extinguish
 * Support for mode-specific population scripts, of the format "population_". New population names will be merged with the base script, matching population names will override the base script.

July 2, 2013
This update also includes an update to the L4D2 Authoring Tools
 * Added the Extended Mutation System
 * Included demo EMS modes Holdout, Dash, L4D1
 * Added support for Linux.
 * Server operators can now specify whether or not custom content is allowed when playing on their servers. This can be set on a per game mode basis - see cfg/addonconfig.cfg for details.
 * Fixed yellow screen corruption that occurs on AMD Radeon HD 6000 Series hardware.
 * Updated database to include video cards from the Steam survey through April 2013.

Add-ons
 * If a found game is using a Mutation add-on from the workshop, the "Download Add-on" button will open the workshop page
 * Adjusted add-on sorting when loading the main menu so Mutation add-ons can override UI elements.
 * Reworked add-on management to improve stability and properly support custom mutations.
 * Fixed the download progress panel sometimes not updating because it was referencing a different file than the one currently downloading.
 * Added a drop-down menu to the add-on screen to filter by tags.
 * Fixed occasional focus problem when clicking on the Addons list panel.
 * Allow keyboard scrolling of the Addons list panel.

Publishing Tools
 * Fixed published file browser not updating after publishing new content.
 * Fixed published file browser showing only the first fifty items of a users workshop.
 * Fixed upload tool throwing an error when replacing an existing file, if the file size was greater than the available space in the cloud.
 * Fixed upload tool sometimes showing an error dialog for files that had been deleted from workshop.

May 24, 2013
Windows

Changes: c11m2 c9m2 c8m1 c8m4 c8m5 Linux
 * Updated some mutations to remove instances of invalid weapons and enemies
 * Fixed Cold Stream image in Campaign select menu
 * Fixed possible insta-kill when shoving a Jockey who is mid-leap
 * Restored freezer door in co-op mode
 * Restored crane lowering sound
 * Broke some barricaded doors so Survivors can reach supplies
 * Restored missing fire particle system
 * Restored color correction for both Crash Course maps
 * Fixed survivors facing the wrong direction after intro
 * Restored alarm clock in downstairs bedroom for co-op mode
 * Restored missing rain particle systems
 * Restored some missing chopper pilot lines
 * Moved survivors out of view during the escape sequence

General EMS
 * Fixed possible insta-kill when shoving a jockey who is mid-leap
 * Fixed Cold Stream image in Campaign select menu
 * Removed ammo piles in Gib Fest Mutation
 * ent.GetEntityIndex
 * ent.EyePosition
 * ent.GiveItem( itemname ) - Give an item/weapon by name. ("health", "katana", "rifle_ak47", etc.)
 * ent.GetButtonMask - Returns a bitfield of currently pressed buttons. Recognized buttons are: IN_ATTACK, IN_ATTACK2, IN_JUMP, IN_DUCK, IN_FORWARD, IN_BACK, IN_USE, IN_MOVELEFT, IN_MOVERIGHT, IN_RELOAD
 * Not tried that one myself, I must admit. Go forth, guinea pigs!

Left 4 Dead 2 update puts an end to insta-killing mid-leap-jockeys

March 21, 2013
Changes:
 * Fixed a possible buffer overflow in keyvalues
 * Fixed player_death event setting "victimname" to "Charger" when the Spitter gets killed.
 * Fixed a bug that sometimes caused the rescue vehicle to arrive immediately when the second team in a versus match started the finale.

March 15, 2013
Left 4 Dead 2 Workshop Manager
 * Updated scheme
 * Added new tags
 * New field for change notes when editing existing workshop items

January 29, 2013
Custom Campaign select screen:
 * Show all installed custom campaigns, not just the ones that support the current mode.
 * Disable list items for campaigns that don't support the current mode, and sort them to the bottom of the list.
 * Fixed some uninitialized text fields when no campaign is selected.
 * Moved an informational string so it doesn't overlap the campaign list.

Workshop Publishing Tool:
 * Removed the file count from the download progress bar to avoid confusion when stale meta-data indicates there are more files than actually exist.
 * Don't show the download progress bar if no valid files were found.
 * Fixed the "Failed to write file chunk..." error message not correctly showing the number of bytes written.

January 24, 2013

 * Fixed Workshop add-ons not mounting correctly on the Mac

January 22, 2013

 * Updated a Steam binary that may have been causing some Windows Dedicated Servers to crash

January 18, 2013

 * Workshop now available for Left 4 Dead 2.
 * Added Workshop Manager upload tool to Left 4 Dead 2 Authoring Tools.
 * Add-ons screen now supports browsing the workshop and subscribing to workshop content.
 * Moved add-on menu option to main menu.
 * Added the ability to filter add-on content by tags.
 * Fixed scoreboard not showing the campaign name for custom campaigns.
 * Fixed "Rescue" label not drawing correctly in the scoreboard for campaigns with more than five maps.
 * Cleaned up DLC add-on file dependencies and simplified talker file picture - the manifest has changed.
 * Fixed an issue where some L4D1 vocalizations that were also present in L4D2 weren't firing.
 * Fixed transition dialog in L4D1 campaigns.
 * Various fixes for character dialog including conversations, weapon spotting, defibs, and other misc audio.
 * Added data on L4D1 characters so corresponding Talker rules would work (i.e. Elevator Speech in No Mercy)

December 11, 2012

 * Updated menu navigation for Big Picture mode so the joystick doesn't always have to be active

November 20, 2012

 * Fixed the Tank's primary attack sometimes choosing different sequences between the client and the server. Fixes hit traces not always matching the visible animation.
 * Fixed the Tank's left-handed attack using the right hand's position for hit traces.
 * Player-controlled Tanks now always choose the right arm horizontal swing sequence for primary attacks. Fixes some attacks not connecting when it appears they should have, due to the inability to predict which swing animation would be randomly chosen.

November 2, 2012

 * Fixed the game and tools not launching on machines with 16+ CPUs.
 * Fixed missing and incorrect music being played in L4D1 campaigns
 * Swamp Fever - The Swamp: Added additional self-terminating survivor-only blockers to the areas above the airplane wreckage to prevent players from skipping the airplane event. These blockers are killed once the airplane door is opened.
 * Cold Stream South Pine Stream: Added a small blocker next to a crate near the military truck near mid-level to resolve a minor stuck spot.
 * Fixed controller navigation in mutation menus

October 25, 2012

 * Fixed fire from incendiary ammo re-igniting itself and never burning out.
 * New achievement: "Good Guy Nick - Plays games with free weekend players and helps them survive a campaign."

October 19, 2012

 * Fixed player movement using joystick settings when playing with keyboard and mouse.
 * Fixed a secure convar warning when scrolling the mouse wheel as a player infected.

October 17, 2012

 * Enable controller navigation of menus to support Big Picture mode.
 * Allow client menus to execute restricted client commands.
 * Fixed special infected not catching fire if they were already burning from incendiary ammo. Hunter and Jockey won't be killed if slashed mid-leap by another infected.
 * Infected damage applied to a Jockey rider is ignored for the Jockey and no longer passed on to the Survivor. This fixes Jockey victims being subject to double damage from infected attacks and instant incap from Tanks.
 * Tweaked boss zombie spawn timing in Versus to prevent the Tank spawning as soon as the Survivors exit the safe room.
 * Fixed the first maps in Dead Center and Swamp Fever not using the boss spawning rules for starting maps, which are more restrictive than other maps.

October 6, 2012

 * Allow custom radial menus to execute restricted client commands

October 5, 2012

 * Added new startup and connection warnings if the player has -insecure in the launch options
 * Protected against a crash in infected ragdolls
 * Added fallbacks to common infected spawning to prevent common crash when population data is missing
 * Fixed a bug that allowed malicious servers to execute restricted console commands on players
 * Fixed a bug that allowed malicious servers to prevent players from executing console commands
 * Fixed incorrect "Survivors Have Escaped" state for Player Infected when a scripted crescendo event is played after a successful finale escape.
 * Update to Confogl mutation to fix a possible crash on team swap
 * If you are receiving an "Error 55" while connecting to dedicated servers, please make sure to accept the Steam Beta update then restart Steam.

September 21, 2012

 * Console commands update_addon_paths and unload_all_addons can't be used while connected to a server.
 * Some custom UI's give the ability to change which add-ons are active from the in-game menu. Now those changes won't be applied until the player returns to the lobby or main menu.
 * Melee weapon scripts can optionally define the HUD icon data inside the script, similar to other weapons. See golfclub.txt for a format example.
 * Fixed a rare crash in the Spitter attack.
 * Fixed a rare crash in bot navigation involving ladders.

August 25, 2012 (Authoring Tools)

 * Added handlers for two crash types that weren't getting picked up by our crash reporting system

August 24, 2012

 * Added protection against possible memory corruption from oddly sized avatar images
 * Added handlers for two crash types that weren't getting picked up by our crash reporting system
 * Added DLC directories to whitelist for consistency checking
 * Flagged whitelist.cfg, motd.txt and host.txt to not clobber local versions on updates
 * Updated some translations

June 24, 2012
CRASH COURSE
 * Made all mutations accessible from the main menu

Crash Course 1: Crash Course 2: DEATH TOLL
 * Fixed survivors being able to climb into infected-only territory from the top of the white truck in the early alley.
 * Survivors can no longer leave the map bounds near the riverfront.
 * Closed off a shortcut method to bypass the howitzer event.
 * Survivors can no longer jump on the generators in the finale area.

Death Toll 1: Death Toll 2: Death Toll 3: Death Toll 4: Death Toll 5: DEAD AIR
 * Moved car near the tunnel entrance away from the drooping traffic light, as standing on parts of the car near the traffic signal could put you into a permanently stuck position.
 * Moved a traffic sign that allowed survivors to climb the drooping traffic light prop up to the top of the tunnel entrance.
 * Added an infected ladder leading in to the upper pipe in the large drain room.
 * Survivors should no longer be able to cross the bridge-lowering event before the bridge has fully lowered.
 * Survivors should no longer be able to access the infected-only areas toward the end of the level.
 * Survivors should no longer be able to leave the playable areas of the map from the areas beyond the saferoom.
 * Added "Checkpoint" flag to the nav square at the end of the intro saferoom to prevent versus rounds from starting when survivors stand next to the door.
 * Removed a nav square by the next-level saferoom door to prevent infected players from standing there to prevent the round ending.
 * Tweaked saferoom level transition trigger brushes to pvetent infected players outside of the saferoom preventing the transition.
 * Players can no longer access the right-hand corner just outside the starting saferoom. This is to address a permanent-stuck spot when the saferoom door is opened.
 * Survivors can no longer climb over the van in the alley leading to the onslaught area, which allowed them to skip most of the level.
 * Survivors should no longer be able to leave the map/enter infected-only areas outside of the onslaught event street.
 * Made the roof of the picnic area inaccessible to survivors. This resolves an invincible spot.
 * Players can no longer jump on the electric box prop facing the water on the side of the lakehouse.

Dead Air 1: Dead Air 2: Dead Air 3: Dead Air 4: Dead Air 5:
 * Moved a bookshelf in front of the window in the second interior area (before the ladder climb) to prevent players from skipping parts of the level.
 * Moved the trailer below the office building out of jumping range to prevent players skipping the offices.
 * Moved the fence and fence-climbing props at the entrance to the construction yard further back into the alleyway.
 * Several tweaks to the area near the construction yard to prevent survivors from setting off the barricade fire event before they enter the event arena.
 * Boarded up a window in the construction yard to address survivors accessing an invincible area.
 * Survivors should no longer be able to jump over the barricade.
 * Infected players should no longer get stuck climbing over the rubble that divides the start of the map from the balcony leading to the escalator side.

Fixed a visual bug caused by a cube map being hidden inside of a prop.

BLOOD HARVEST

Blood Harvest 1: Blood Harvest 2: Blood Harvest 4: Blood Harvest 5: COLD STREAM
 * Survivors should no longer be able to leave the map by jumping to the left toward the end of the rope bridge..
 * It is no longer possible for survivors to climb in the vent above the alarm room.
 * Survivors can no longer stand on the horizontal pipes under catwalk in the area following the alarm door event.
 * The high pipes along the sides of the train tunnel are no longer accessible to survivors.
 * The roof of the starting safe room is no longer accessible to survivors..
 * Survivors can no longer jump on top of the "Richardson Atlantic" building.
 * Removed some of the crossbeams in the hay storage building.

Cold Stream 1: Cold Stream 2: Cold Stream 3: Cold Stream 4:
 * All infected can now access the roof of the watchtower.
 * Survivors can no longer jump on top of the roof of the single-storey cabin at the far end of the area after the rope bridge.
 * It should no longer be possible for survivors to jump up to the top of the tunnel entrance pipe near the start of the map.
 * Survivors should no longer be able to jump over the fence on the bridge toward the end, skipping the barrel explosion event.
 * Changed the M60 spawns into weapon_item_spawn to be more mutation friendly.
 * The walls toward the back of the bridge (opposite of the direction players go to progress the level) are no longer accessible to survivors. This is to prevent survivors from getting into infected-only areas below the bridge, which they may not be able to escape from.
 * Changed the M60 spawns into weapon_item_spawn to be more mutation friendly.
 * Hooked up a quick conversation between the chopper pilot and the triggering survivor.

June 16, 2012

 * Next Mutation: Nightmare
 * Fixed an exploit that allowed banned players to bypass the ban

May 26, 2012
Changes: Dead Center 1: Dark Carnival 3: Hard Rain 2: Hard Rain 1/5: The Passing 1:
 * Next Mutation: Flu Season
 * Removed a demo ConVar that was being used for an exploit
 * The lower windows should no longer be accessible (versus map grief).
 * Adjusted brush that was blocking a truck interior, to no longer block the truck interior.
 * Adjusted the rollercoaster event start to make it more difficult to skip.
 * Adjusted blockers on the pipe-hop shortcut to provide better coverage.
 * Adjusted blockers to better cover the added box which itself covers an invincible spot.
 * Added blockers for survivors along the railings in the upper areas to prevent them from leaving the map or getting stuck out of bounds

April 20, 2012
Today's update includes fixes that will be coming to the Xbox 360 in a future update.

Dead Center:

The Hotel: The Atrium: Dark Carnival:
 * Made dropping between the top two floors much more difficult.
 * Survivors should no longer be able to jump onto the vending machines near the start of the map, as AI infected could not see or path to this area.
 * Blocked Survivors being able to stand on the map placard, as this was a spot where infected could not path to.

The Highway: The Fairgrounds: The Coaster: The Barns: The Concert:
 * Survivors should no longer be able to jump on top the truck near the ending saferoom, as AI infected are unable to attack survivors there.
 * Survivors can no longer climb on top of an early set of generator lights.
 * Made dumpster near the first warehouse session into a static prop to prevent grief blocking map progress.
 * The forklift near the entrance to the building leading to the silly slide has been removed.
 * Blocked survivors being able to stand on a maintenance structure near the back wall by the carousel, as AI infected were unable to see survivors if they zombie-hopped their way up there.
 * Blocked top of the back wall next to above for the same reason.
 * Blocked a hop up on a light post base where survivors in VS could glitch their way to 100% map completion.
 * Blocked access to a stuck spot behind some stairs in the swan maintenance room.
 * Blocked survivors being able to jump on the shelf next to the stuck spot. Infected were unable to see survivors standing there.
 * Blocked being able to climb into the shelved swan in maintenance, as infected could not see survivors that were there.
 * Blocked survivors from jumping on several electric box props shortly before the coaster event, which could be used as invincible spots.
 * Blocked a method of climbing and skipping the roller coaster event start.
 * Blocked survivors being able to be knocked into the infected-only trash area next to the covered picnic area near the start. Players knocked over this fence could not make it back.
 * Blocked survivor access to the windows above the concert to remove an invincible spot.

SWAMP FEVER:

Plank Country: The Swamp:
 * Added a bunch of dock props to break up a pair of invincible spots at the ferry panic event.
 * Skipping the airplane event should now be much more difficult.

HARD RAIN:

The Sugar Mill: Mill Escape: Town Escape:
 * Blocked a hop-up onto some pipe-work that allowed survivors to skip the conveyor belt section.
 * Blocked access to a very tiny ledge opposite the elevator at the holdout event, which was an invincible spot.
 * Blocked survivors being able to jump onto the roofs near the start which allowed them to avoid the sugar cane field altogether.
 * Added a few props to block access to a table in the restaurant, which was an invincible spot.
 * Blocked survivors being able to climb on top of the generator, another invincible spot.
 * Removed an invincible spot off the dock.

THE PARISH:

The Waterfront: The Park: The Cemetery: The Quarter:
 * Added a few props for infected to climb out from a garden behind a wall, which had previously been inescapable.
 * Blocked survivors from jumping on the generator and the tops of the metal fences just after the park area, removing an invincible spot.
 * Blocked access to an out-of-map exploit area which was reachable by climbing an electrical box prop.
 * Blocked survivors getting on top of the white trucks near the end of the alarmed car lot, as these were invincible spots.
 * Blocked survivors from jumping the fence from the shed into inescapable infected-only territory following the bridge explosion.
 * Blocked players following the highway to the end of the map, which led to a spot where players could get under the map.
 * Blocked being able to hop back up a one-way drop following the pool hall.
 * Blocked survivor access to the landing exiting the parade float event zone until the event itself has been started.
 * Blocked player infected from perching in a high window in the ending saferoom, which could prevent a VS round from ending.

THE PASSING:

The Riverbank: The Port:
 * Block infected ghost players in VS from getting under the map by crossing the bridge at the start.
 * Block infected from leaving map bounds by going beyond the first area, and slipping past the water kill brush.
 * Block survivors jumping the fence just after the first interior, allowing them to leave the map bounds.
 * Block an out-of-map exploit near the wedding party area.
 * Block an infected out-of-map exploit near the saferoom.
 * Survivors will no longer be able to stand on the indoor generator and access rooftop areas.

THE SACRIFICE:

The Port: NO MERCY:
 * Survivors will no longer be able to stand on the indoor generator and access the rooftop areas.

The Apartments: COLD STREAM
 * Adjusted player blocker for the corner drop safe-landing at the start to be slightly larger.
 * Added blockers to both air conditioning units near the start to prevent survivors from using them to skip the apartments.

Cut-Throat Creek:
 * Fixed a stuck spot in the rocks above the river tank fight.

April 13, 2012

 * Next Mutation: Last Man on Earth

March 29, 2012

 * Next Mutation: Versus Survival

March 16, 2012 (Patch 1)
General: No Mercy 1 - Apartments: No Mercy 2 - Subway: No Mercy 3 - Sewer: No Mercy 4 - Hospital: No Mercy 5 - Rooftop: Cold Stream 4 - Cut-throat Creek:
 * Fixed survivors being able to climb some infected-only ladders
 * Survivors should no longer be able to fall into the street-level infected-only area from the starting rooftop -Players should no longer be able to drop down onto the invisible brush at the corner.
 * Survivors should no longer be able to incapacitate themselves by jumping toward the electric box prop opposite the starting rooftop. It should now be fatal
 * Players should no longer get stuck when in the back corner underneath the starting room
 * Survivors should no longer be able to jump onto the tiny ledge on the side of the building following the door/generator event
 * Made the piano near the ending safe room into an immobile, static prop to solve an issue with infected players using it to block the safe room.
 * Survivors who somehow manage to get on top of the gas station should no longer be able to leave the map.
 * The work light at the mid-way point in the sewer is now an immobile, static prop to solve an issue with infected players using it to block survivor progress.
 * Added the missing "breakable" decals to the breakable wall in the second part of the stairwell.
 * Made the breakable wall in the second part of the stairwell breakable to all infected.
 * Survivors should no longer be able to enter the infected-only vents and passages above and near the elevator event.
 * The two tank-only breakable walls in the upper, under construction floor can now be broken by any infected.
 * Added several props to cover and remove an invincible spot on one of the lower tiers of the rescue rooftop.
 * Fixed infected not being able to path to survivors when standing in the boat near the tank fight.

March 16, 2012 (Patch 2)

 * Temporarily removed a change that broke a ladder in Dark Carnival.

February 17, 2012
General: Crash Course 1: Crash Course 2: Dead Air 3: Blood Harvest 4: Blood Harvest 5: Cold Stream 1: Cold Stream 2: Cold Stream 3: Cold Stream 4:
 * 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.
 * 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.
 * 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.
 * 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.
 * Widened the gap in the railing on the final bridge.
 * Falling off the cliff or the final bridge is now fatal to both teams.
 * Fixed a potential bug for low-end machines where certain walls and textures near the starting safe room would vanish in certain views.
 * There is now only a single hunting rifle in the cabin after the rope bridge.
 * 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 recude the chances of players getting caught on geometry.
 * New infected ladders added.
 * Added a weapon to 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.
 * 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.
 * 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.

February 3, 2012
Blood Harvest campaign: Blood Harvest 3: Blood Harvest 4: Blood Harvest 5:
 * Item density revision.
 * Several minor bugs fixed.
 * Fixed a potential exploit where survivors were able to jump off onto the cliff side prior to the train onslaught.
 * Added tooltip to prompt players to fight to the safe room when the onslaught begins.
 * Changed the lights on first large train depot building to be non-solid, to prevent survivors to be able to jump into the upper windows.
 * Moved a bookshelf in front of a window on the ground-floor of the last building in the level.
 * Adjusted the slope of the concrete that makes up the bottom section of the last building in the map so that players slide off of it. It was previously used as part of an exploit to skip content.
 * Doubled the height of the fence that leads around the last building in the map to prevent players from skipping the final building.
 * Added tooltip to prompt players to fight to the safe room when the onslaught begins.
 * Added a new spawn location on the final bridge for infected.
 * Removed a piece of railing along the final bridge to create an opening for infected attacks.
 * It should now be much harder to get stuck inside of the APC when it arrives.

January 27, 2012
Dead Air 2 - The Crane: Dead Air 3 - The Construction Site: Dead Air 4 - The Terminal: Dead Air 5 - Runway Finale: Death Toll 5 - Boathouse Finale:
 * Item density revision
 * Various minor bugs fixed.
 * Fixed bug where the tooltip for the Crane Event would appear near the start of the map instead of near the crane.
 * Fixed an exploit where survivors could skip the crane event by jumping onto the fence and across the gap.
 * Removed hotel luggage carts to prevent survivors from having their progress blocked.
 * Removed an exploit where survivors were able to jump from the roofs following the crane to the ground, skipping the office section entirely.
 * Fixed a case where an SI ladder was being blocked by a door prop in the construction site.
 * Fixed an invisible wall in a resscue closet in the construction site.
 * Fixed a bug where the Van event tooltip would appear at the start of the map, instead of when nearing the van itself.
 * Tweaked van event start so that the horde begins after the van begins to make noise, not before.
 * Added tooltip to prompt players to fight to the safe room when the onslaught begins.
 * Added an info_director entity.
 * Swapped out L4D2 mounted gun for the L4D1 mini-gun.
 * Fixed a bug where the survivor closet doors near the finale could not be broken by infected players until the finale started.

January 20, 2012
Death Toll 1: Death Toll 2: Death Toll 3: Death Toll 4: Death Toll 5:
 * Item density pass.
 * Minor visual bugs fixed across all maps.
 * Fixed a case where several rock props were intruding through a wall near the safe room.
 * Fixed a case where survivors could jump into infected-only areas using an electrical box in the bridge holdout room.
 * Removed an exploit where players could jump from the wheel pedestal of a flarcar onto a train car to skip the balcony area and exit the trainyard.
 * Altered the PZ spawn area near the trainyard exit. Instead of a tanker and a pile of gravel, it is now an overturned truck and van.
 * Church Guy zombie returns!
 * Blocked survivors jumping onto the left bus from the fence near the start, which allowed the allowed player to skip the beginning of the map.
 * Fixed pipe hanging in the middle of a room during end-level onslaught.
 * Removed the mounted gun, as this was causing players trying to outlast an infinite horde.
 * Added tooltip to prompt players to fight the safe room when the onslaught begins.
 * Fixed a case where survivors could climb an electrical box prop into infected-only areas during the onslaught.
 * Fixed end-level trigger size exploit, which allowed players to stall the end of the map trigger by standing on top of a water-cooler.
 * Swapped out the L4D2 mounted gun for the L4D1 minigun.

January 16, 2012

 * Fix for Windows Dedicated Servers operating in LAN mode only.

January 13, 2012
General:
 * Added game event calls for onslaughts to explain to players that they need to fight their way to the safe room. Modders can make use of this by pointing an info_game_event_proxy entity to "explain_onslaught"
 * All maps received minor tweaks and bug fixes, the significant changes are listed.

Crash Course 1 - The Alleys:
 * Item spawn density revision.
 * Opened the side-doors leading to potential item spawns.
 * Switched out L4D2 mounted gun for the L4D1 minigun.
 * Removed exploit where survivors could get onto a roof near the drop down to the river.

Crash Course 2 - The Truck Depot Finale:
 * Item spawn density revision.
 * Switched out L4D2 mounted gun for the L4D1 minigun.
 * Removed exploit where survivors could jump onto the top of a generator during the finale.

Cold Stream 1 - Alpine Creek:
 * Fixed water moving uphill in some spots.

Cold Stream 2 - South Pine Stream:
 * Removed "shortcut" through the bushes between a pair of barricades leading to the barrel explosion event.
 * Added tooltip to prompt players to fight to the safe room when the onslaught begins.
 * Turned the horde numbers back a bit during the onslaught event.
 * Moved the sun to help guide new players.
 * Blocked ability to get under the river.

Cold Stream 3 - Memorial Bridge:
 * Added many more infected ladders around buses.
 * Rebuilt catwalk under the bridge to prevent players getting caught on geometry.
 * Moved the M60 and Laser Sights upgrade to more vulnerable locations.
 * Removed ammo pile in the shop just before the junk yard, but kept the weapons.

Cold Stream 4 - Cut-throat Creek:
 * Added some light cover for the Tank in the basin area.
 * Removed survivor manhole exit into the second half of the map.
 * Added side-hall in the sewer as a shortcut for infected players going to the second half of the map, and as a strategic place to spawn in the sewer.
 * Added new truck depot area near the tower for infected to spawn in.
 * Opened a warehouse door for infected to spawn in.
 * Added infected ladders in the CEDA checkpoint area.
 * Rebuilt stairway up the finale tower to prevent players getting caught on geometry.

January 11, 2012 (Patch 1)

 * Fixed a bug where server tags were getting truncated, preventing players from finding Steam Group servers.
 * Updated video card data base with the latest hardware

January 11, 2012 (Patch 2)

 * Reverted some new driver settings that caused bad glows on some video cards

December 20, 2011

 * Adjusted Holiday Gift drop frequency

December 16, 2011

 * Fixed Tank Spawning issue in Finales
 * Fixed issue in Boat House finale where winning survivors would die on the boat
 * Added new achievement, Valve Gift Grab 2011 – L4D2
 * Added I Hate Mountains 2 as the featured community campaign
 * Added blocklist functionality to Left 4 Dead 2
 * Undocumented: Added melee weapon lists to original campaigns and Cold Stream

November 18, 2011

 * Mutation: Headshot!
 * Fixed a few missing or invalid entries in campaign menus.
 * Fixed a long-standing bug that could cause occasional memory corruption or crashes on level transitions.

November 4, 2011

 * New Community Mutation: Confogl
 * Crash Course campaign
 * Fixed intro music not playing in some campaigns
 * Fixed some missing survivor audio

October 21, 2011

 * Encore Mutation: Iron Man

October 12, 2011

 * Fixed an issue that prevented some Add-Ons from loading if there were a significant number of unique audio files

October 7, 2011
Death Toll: The Boathouse Cold Stream: Cut-Throat Creek
 * Encore Mutation: Gib Fest
 * Added VCVAR_RELEASE to the following rcon cvars: sv_rcon_minfailures, sv_rcon_minfailuretime, sv_rcon_maxfailures, sv_rcon_banpenalty and sv_rcon_log
 * Fixed a bug with processing entity packets.
 * Fixed various audio bugs for the Left 4 Dead 1 Survivors.
 * Moved rope barrier closer to dock.
 * Added rock for Infected Specials to spawn behind.
 * Moved melee weapon spawn off picnic table to avoid floating weapons.
 * Redesigned start of map. There is missing Audio, use the handset and then the door in the big building to begin.
 * Removed the ability for Common Infected to spawn on top of ridge along the first ravine.

September 23, 2011
Left 4 Dead 2
 * Fixed configurable weapon spawns not allowing Confogl mutation to override spawn behavior
 * Encore Mutation: Healthpackalypse

September 16, 2011
Death Toll campaign released Blood Harvest; The Bridge Blood Harvest: The Train Station
 * Fixed scoring in finale
 * Infected will spawn in front of the survivor team on their way to the Safe House.
 * Added Infected spawn locations on the hill by the Safe House.
 * Fixed exploit that allowed Infected team to trigger the onslaught.

September 9, 2011

 * Encore Mutation - Hunting Party
 * Dead Air: The Crane - The alarm car is now disabled until you are on the street
 * Dead Air: The Construction Site - Blocked windows to prevent early triggering of the Crescendo event

September 2, 2011

 * Bots now get into the rescue vehicle on the Dark Carnival finale

August 26, 2011

 * Encore Mutation: Versus Survival
 * Fixed issue where Male survivors wouldn't speak lines if Nick was dead

August 18, 2011

 * Fixed Blood Harvest Finale scoring.
 * Fixed missing skybox in Blood harvest with low shader settings.
 * Fixed campaign search filter dropdown missing Dead Air, Blood Harvest, and Cold Stream.

August 12, 2011

 * Encore Mutation: Healing Gnome
 * Blood Harvest Beta Campaign

August 9, 2011

 * Fixed issue with awarding the "Connecting Fights" achievement

August 6, 2011

 * Fixed corrupted scripts for the 4th map of Dead Air
 * Removed legacy UI audio

August 5, 2011

 * Updated Dead Air Campaign
 * Added "Connecting Fights" Achievement

July 30, 2011

 * Fixed Poll Question

July 29, 2011

 * Encore Mutation: Taannnkkk

July 27, 2011

 * Updated Dead Air
 * Made change to prevent rushing issue in The Terminal.
 * Removed truck roof exploits in finale.
 * Added Infected entry points to respawn closet in finale.
 * Fixed finale scoring.
 * Remove defib from Versus Finale.

July 22, 2011

 * Beta release of Dead Air Campaign

July 15, 2011

 * Encore Mutation: Bleed Out Versus
 * Decreased the spawn distances in finales
 * Pressing the use key (default "E") during a finale while in ghost spawn mode will teleport the infected player to a survivor's location

July 1, 2011

 * Encore Mutation: Lone Gunman
 * Cold Stream, map 3
 * Fixed a missing texture on a sign at the beginning of the map

June 27, 2011

 * Updated Cold Stream Beta campaign
 * Known Bug - No audio for radio. Use the radio twice to activate the finale.

June 17, 2011

 * Encore mutation: Hunting Party
 * Fixed double scoring bug when Survivors would incapacitate themselves in the safe room.
 * Dark Carnival The Concert: Fixed invulnerable spot on top of the plywood.

June 3, 2011

 * Encore mutation: Versus Survival

May 20, 2011
Left 4 Dead 2
 * Encore mutation: Gib Fest
 * Localization updates to all languages

May 6, 2011
Left 4 Dead 2

Encore mutation: Taannkk!

Dead Center - The Mall Dark Carnival - The Barns The Parish - The Waterfront The Parish - The Quarter Cold Stream To help with public testing, we fixed more buugs and exploits than we normally would on maps that are still in a transitional state. We are holding off on many changes to the finale right now as that map will change the most.
 * Survivors can no longer bypass the storefront mini-finale.
 * Survivors can no longer bypass the barn interiors.
 * Removed the Survivor zombie-jump exploit in the first alley.
 * Survivors prevented from using short cut over the top of the fence.
 * Various bug and exploit fixes for the first 3 maps.
 * Added survivor respawn closets - some temporary while we work on the maps.
 * Added navigational aids to maps.
 * Changed the first map's ending as an experiment - please give feedback!
 * Added alternate route around boat mast - please give feedback.

April 27, 2011
Left 4 Dead 2
 * Fixed a crash on Intel Sandybridge parts when turning up graphics options

April 22, 2011
Left 4 Dead 2 The following map fixes are part of an ongoing series of exploit fixes. These will appear on the Xbox 360 in a future update.
 * Encore Mutation: Survival Versus

Swamp Fever: Swamp
 * Survivors can no longer bypass the airplane crescendo event.
 * Swamp Fever: Shanty Town


 * Survivors can no longer use a shanty roof to bypass a large section of the map
 * Swamp Fever: Plantation


 * Survivors can no longer bypass the first street by walking on top of a fence

April 8, 2011
Left 4 Dead 2 The following map fixes are the first of a series of exploit fixes coming. These will appear on the Xbox 360 in a future update.
 * Encore mutation: Last Man on Earth
 * Fixed some missing particle declarations for the Cold Stream campaign

Dark Carnival: The Fairgrounds Dark Carnival: The Coaster The Parish: The Park The Parish: The Cemetery
 * Survivors can no longer get onto the elevated track.
 * Infected players can no longer block the carousel gate.
 * Survivors can no longer skip the roller coaster crescendo event
 * Survivors can no longer use shortcuts on the roller coaster
 * Survivors can no longer skip the bus station crescendo event
 * Survivors can no longer skip interiors by jumping over a fence or getting onto rooftops

March 24, 2011
Left 4 Dead 2
 * Encore mutation: Last Gnome On Earth
 * Cold Stream
 * Fixed audio cache's for intro/outro audio
 * Fixed spawning outside of safe rooms on map transitions

March 23, 2011
Left 4 Dead 2
 * In-game bug reporting activated

Beta Version of Cold Stream Campaign Released
 * If you have a problem with a spawn room, vote to restart that chapter.
 * Everyone needs to be by the radio headset to start the finale map.
 * There are bugs, this is a work in progress. Please read the blog for more information

March 11, 2011
Left 4 Dead 2
 * Encore Mutation: Follow The Liter
 * Added support custom campaign particles. Custom campaigns can specify their own particles_manifest.txt file as well as any per map files. The per map files need to reside in the maps directory and be in the form: _particles.txt

February 25, 2011
Left 4 Dead 2
 * Mutation Classic #2: Bleed Out

February 24, 2011
Left 4 Dead 2
 * Improved performance for a range of ATI graphics parts

February 23, 2011
Left 4 Dead 2
 * Improved performance for a range of ATI graphics parts

February 15, 2011
Left 4 Dead 2
 * Newer version of Death's Door Mutation with fewer defibs

February 11, 2011
Left 4 Dead 2
 * New Community Mutation: Death's Door

February 2, 2011 (2.0.5.8)
Left 4 Dead 2
 * Fixed a console command exploit that could be used to crash dedicated servers

January 28, 2011 (2.0.5.7)
Left 4 Dead 2
 * New Community Mutation: Nightmare

January 14, 2011 (2.0.5.6)
Left 4 Dead 2
 * New Community Mutation: Riding My Survivor
 * Added support for raw mouse input on PC. Raw input reads directly from the mouse, bypassing Windows control panel mouse settings. This addresses issues with high DPI mice, and provides for a more reliable controller experience at various resolutions
 * Improved Support for mouse acceleration, for use with raw mouse input
 * Fixes for stability issues on some Intel chips
 * Various rendering fixes for Mac

December 31, 2010 (2.0.5.5)
Left 4 Dead 2
 * Community Mutation: Flu Season

December 17, 2010 (2.0.5.4)
Left 4 Dead 2
 * Community Mutation: Special Delivery
 * Added protection against servers executing restricted commands on clients
 * Fixed clients sometimes not getting disconnected from the server after getting a consistency error
 * Fixed an exploit that could cause players to fall through the elevator in No Mercy
 * Fixed the still-crownable witch in Realism Versus

December 3, 2010 (2.0.5.3)
Left 4 Dead 2
 * Encore Mutation: Hard Eight
 * Fixed dedicated servers not launching if "hl2" was in the installation path
 * Allow m60s to spawn on original campaigns for mod use.
 * Fixed edge case to prevent Infected Players from cycling to survivors whose glows have nearly faded.
 * Tweaks to survivor health glow settings to make states easier to recognize.
 * Fixed a glow color transition point that was off by one.
 * Added cvars to control the behavior of survivor health glows
 * cl_glow_survivor_health_bleed_pulse
 * cl_glow_survivor_health_bleed_pulse_speed
 * cl_glow_survivor_health_bleed_pulse_amount
 * cl_glow_survivor_health_include_buffer

Gameplay
 * Increased spawn times slightly for special infected in Realism Versus.
 * Removed ability to crown witches in realism game modes

November 19, 2010 (2.0.5.2)
Left 4 Dead 2
 * Encore Mutation: Gib Fest!

The following changes are for the PC and will be available for the Xbox 360 in a future update.

Competitive Modes
 * Removed Special Infected spawn music in competitive modes.
 * Added a glow outline to the witch, visible only to the infected team.
 * Added cvar "director_allow_infected_bots" for confogl and other configs.
 * Survivor health glow changes:
 * Adjusted glow color transitions to match movement speed transitions.
 * Use combined regular and temp health when calculating glow color.
 * Glow pulses slightly when the Survivor is on temp health.
 * Realism Versus
 * Cut Special Infected spawn times by half in Realism Versus.

All
 * Fixed limping Survivors moving slightly faster in water.
 * Fixed voice recording intermittently stopping on Mac OS X
 * Client-side plugins
 * Clients must run with –insecure to load unsigned plugins.
 * Insecure clients cannot connect to secure servers.
 * Servers can opt to allow insecure clients by running with –insecure.
 * Secure clients can connect to both secure and insecure servers.

November 12, 2010 (2.0.5.1)
Left 4 Dead 2
 * Encore Mutation: Taaannnkk!!!
 * A vote-kick ban is now applied to players even if they disconnect during voting
 * Additional script commands are cheat-protected

November 5, 2010 ( 2.0.5.0)
Left 4 Dead 2
 * New Mutation: Healing Gnome
 * Pressing E while in ghost mode will teleport you to the next visible player
 * Voting has been restricted to stop vote spam

October 29, 2010 (2.0.4.9)
Left 4 Dead 2
 * New Mutation: Bleed Out Versus
 * Tank speed is no longer reduced when on fire
 * Fixed team votes passing without a majority from both teams
 * Fixed a bug where the add-on list could become unresponsive to mouse input
 * Protected against some console commands that could be used to lag or crash servers

October 23, 2010 (2.0.4.8)
Left 4 Dead 2 Xbox 360 dedicated servers
 * Fixed versus servers sometimes shutting down before both teams have fully connected.
 * Fixed No Mercy door exploit

October 22, 2010 (2) (2.0.4.8)
Left 4 Dead 2
 * Fixed versus servers sometimes shutting down before both teams have fully connected

October 22, 2010 (1) (2.0.4.7)
Left 4 Dead 2
 * New Mutation: Lone Gunman

October 20, 2010 (2) (2.0.4.7)
Left 4 Dead 2
 * Fixed lobbies not being able to join Steam Group servers

October 20, 2010 (1) (2.0.4.6)
Left 4 Dead 2
 * Fixed the fix of the fix of the fix of the door exploit in No Mercy

October 15, 2010 (2.0.4.5)
Left 4 Dead 2
 * New Mutation: Hunting Party
 * Fixed door exploit in No Mercy
 * Now Allow thirdperson settings in cooperative game modes
 * Fixed add-on campaigns not always appearing in the campaign selection screen
 * Restored dedicated server support for add-on campaigns
 * Fixed some rendering artifacts on Mac
 * Added support for Russian audio in The Sacrifice and No Mercy
 * Game correctly recognizes the audio language set in Steam

October 7, 2010 (2.0.4.2)
Left 4 Dead 2
 * Fixed missing subtitles
 * Re-enabled the "wait" command, fixes a hang at startup
 * Fixed several crashes that were reported to our crash database
 * Fixed some addon content eclipsing game content even when not playing an addon campaign. This resolves several issues with missing or incorrect models, textures, and effects. This fix temporarily affects the ability to host custom campaigns on dedicated servers. We are working to restore that functionality as soon as possible.

October 5, 2010 (2.0.4.1)
Left 4 Dead 2
 * Game is fully playable on the Mac platform.
 * Fixed a few third person camera cheats.
 * Added "The Sacrifice" content.
 * Added "No Mercy" content.
 * Versus: Infected players will get a respawn time reduction against teams that rush.
 * Removed need for Left 4 Dead 2 Add-on Support for Community Campaigns

September 24, 2010 (2.0.3.8)
Left 4 Dead 2
 * Dev Choice Mutation: Versus Survival

September 17, 2010 (2.0.3.7)
Left 4 Dead 2
 * Dev Choice Mutation: Healthpackalypse

September 10, 2010
Left 4 Dead 2
 * Dev Choice Mutation: Follow The Liter

September 02, 2010 (2.0.3.6)
Left 4 Dead 2
 * Developer Choice - Hard Eight.
 * Fixed a remote DLL loading exploit (MS KB2264107).
 * Fixed a crash when disconnecting a rcon connection due to an invalid password when multiple sessions were already connected.

August 27, 2010 (2.0.3.5)
Left 4 Dead 2
 * Encore mutations: Gib Fest (PC) and Chainsaw Massacre (Xbox 360)
 * Fixed accessing corrupted sentence data after flushing sound caches, likely the cause of an audio crash.

August 20, 2010 (2.0.3.4)
Mutation
 * Developer Choice - Last Man On Earth

UI
 * Added vote option to enable All Talk in Versus.
 * Added vote option to Restart Chapter in Versus.
 * Added the ability in the lobby for all players to vote on starting the game.

Gameplay
 * Removed Defibs and First Aid Kits in Realism Versus. Survivors start with a First Aid Kit, but all world spawns are disabled.

Addons
 * To avoid conflicts between Community Campaigns, only content vpks get loaded when starting a campaign.
 * Added console command "show_addon_load_order" that prints out the order of loaded vpk files.

Authoring Tools
 * VPK files now support their own sound.cache file.
 * Use the command "snd_buildsoundcachefordirectory " to create the sound.cache file that you should include when you create your vpk file.

August 13, 2010
Left 4 Dead 2
 * New Mutation: Iron Man
 * Fixed Russian localization strings

August 6, 2010 (2.0.3.2)
Left 4 Dead 2
 * New Mutation: Gib Fest!
 * Localization updates and fixes

July 31, 2010 (2.0.3.1)
Left 4 Dead 2
 * Fixed bug in Versus-Survival where a team could get 5 survivors

July 30, 2010 (2.0.3.1)
Left 4 Dead 2
 * Encore mutation: Versus Survival (PC), Four Swordsmen of the Apocalypse (Xbox 360)
 * Added a setup timer to Versus Survival
 * Fixed an exploit that dropped players from dedicated servers

July 28, 2010 (2.0.3.0)
Addons
 * Client's custom HUDs will be reloaded when changing between Official and Non-official servers.

GamePlay
 * Bullets that first pass through an infected character before striking a Survivor are now ignored as friendly fire.
 * Fix for survivors speaking The Passing Finale lines in other campaigns.

Versus
 * Charger now receives 300 points for any Survivor that is insta-killed.
 * Charger now receives 100 points for any Survivor that is insta-incapped by a charge.
 * Any infected that causes a Survivor to stumble into a "ledge hang" situation will receive 50 points.

Tank
 * Tanks go into a stasis when they spawn and leave stasis when the human player takes over.
 * Tanks in stasis are invisible but still show a glow to the infected team.
 * Tanks do not attack when they are in stasis.
 * Tanks in stasis cannot be set on fire or damaged.

SDK Tools
 * Fixed crash whenever a VMT was loaded in L4D2 tools mode.

July 23, 2010 (2.0.2.9)
Left 4 Dead 2
 * New mutation: Healthpackalypse!

July 21, 2010 (2.0.2.8)
Left 4 Dead 2
 * Added additional protection for critical files
 * All add-on files will be loaded when connecting to a Non-Official server regardless of game mode
 * Only approved custom maps will be loaded when connecting to an Official server
 * Player's can print the contents of the consistency list with "cl_print_consistency_list". If the server has sv_consistency disabled, the user will be notified when they attempt to print the list
 * Improvement to Hammer load times

July 16, 2010 (2.0.2.7)
Left 4 Dead 2
 * New mutation: Hard Eight

July 9, 2010 (2) (2.0.2.6)

 * Removed left4dead2\pak02_dir.vpk from the whitelist.

July 9, 2010 (1) (2.0.2.6)
Left 4 Dead 2
 * New mutation: Four Swordsmen of the Apocalypse

Addon Changes
 * By default in single player and co-op gamemodes custom content will eclipse game content.
 * Addon campaign's custom content now loads first to avoid conflicts.
 * In competitive modes addon loading is a server option.
 * Fixed an exploit that allowed people to modify materials on pure servers.
 * Default consistency checks now include pak01_dir.vpk. Addon authors should not hack the pak01_dir.vpk directly but instead include content in a VPK.

Server changes
 * The "whitelist.cfg" file located in the "steamapps\common\left 4 dead 2\left4dead2" directory is now functional. Instructions on how to use this file are located in the file itself. Basically this allows the server operators to decide what files need consistency checks.

July 2, 2010 (2.0.2.4)
Left 4 Dead 2
 * New mutation: Versus Survival
 * Updated default configuration for Intel HD Graphics card

June 25, 2010 (2.0.2.3a)
Left 4 Dead 2
 * Encore mutation: Chainsaw Massacre

June 18, 2010 (2.0.2.3)
Addon Update
 * Fixed a crash when the vpk file limit was reached.
 * Fixed an issue where wireframes were displayed while playing Addon Campaigns.

Versus Updates
 * Added a 25-point scoring penalty for using a Defibrillator.
 * Scaled dynamic Defibrillators based on map length with a maximum of 1 per map.
 * Removed dynamic Pill conversion to First Aid Kits.
 * Removed Explosive Ammunition.
 * Increased Jockey damage per second.
 * Removed Jockey's damage delay.

June 11, 2010 (2.0.2.2)
Left 4 Dead 2
 * New mutation: Room For One.
 * Improved SurvivorBot's ability to support players who stop moving to fight infected.
 * Improved SurvivorBot's ability to support players in tight spaces.

Match Making Changes
 * Server searches for Official Dedicated servers no longer automatically fall back to Best Available. Lobby leaders will be given the option.
 * Lobby leaders can select "Steam Group Server" as a server option. This will allow them to select individual servers.

June 9, 2010 (2.0.2.1)
Left 4 Dead 2
 * Changed Survivorbot item hunting behavior
 * SurvivorBots now stay closer to human players in all game modes
 * Fixed Survivorbot navigation issue in The Passing: Riverbank
 * Fixed bug where a SurvivorBot could become catatonic when attempting to save another Survivor from a Smoker
 * Fixed condition where SurvivorBots would not enter the saferoom
 * Increased self-inflicted friendly fire damage from the Grenade Launcher
 * Fixed bug where the M60 would reset its ammo if dropped in certain situations
 * Car Alarms will now trigger anytime a Special Infected pushes/pulls/rams a Survivor into an alarm car. This change only affects game modes with human-controlled Infected.

June 4, 2010 (2.0.2.0)
Left 4 Dead 2
 * New mutation: Chainsaw Massacre
 * In Versus Special Infected bots spawn within 10 seconds of the Survivors leaving the safe room
 * Shortened spawn times for human Special Infected when the Infected team isn't full. The time difference is added to the timer of the next bot in line to spawn
 * Exposed client console variable cl_viewmodelfovsurvivor to let players adjust their viewmodel FOV
 * To use this type cl_viewmodelfovsurvivor ## in the console. ## can be any number from 0-128 the default is 51

May 28, 2010 (2.0.1.9)
Left 4 Dead 2
 * New mutation: Last Man On Earth
 * Blocked a map exploit at the start of The Passing
 * Fixed a crash if a Spitter lost her spit target mid-attack
 * Updated video config for new NVIDIA cards

May 21, 2010 (2.0.1.8a)
Left 4 Dead 2
 * Encore mutation: Last Gnome On Earth
 * Realism Versus added as a permanent game mode
 * Lobbies now default to "Official Dedicated"

April 30, 2010 (2.0.1.6)
Left 4 Dead 2
 * Fixed original survivors cheating in Bleed Out mode by throwing first aid kits

April 27, 2010 (2.0.1.5)
Left 4 Dead 2
 * Fixed addons content not loading if coop was the first game mode loaded
 * Fixed versus modes sometimes using incorrect game rule settings after server hibernation
 * Fixed a crash in The Parish: The Park on Linux dedicated servers
 * Updated dlc1 Russian UI text

April 23, 2010 (2.0.1.4)
Left 4 Dead 2:
 * Fixed the localization sound caches
 * Fixed AI tanks sometimes not getting assigned to human players
 * Fixed exploit in C5M2 where players could jump through a gap in the fence
 * Fixed commentary maps crashing on load

SDK:
 * Removed Perforce integration and Manifest UI when running Hammer under and SDK deployment
 * Removed Version control menu for SDK
 * Material nudging only works if the user has nudging enabled

April 22, 2010 (2) (2.0.1.3)
Left 4 Dead 2:
 * Fixed SDK load Issue
 * Fixed Mutation Achievement display

April 22, 2010 (1) (2.0.1.2)
The first game add-on for Left 4 Dead 2 brings the original Left 4 Dead Survivors down south for a meeting with the L4D2 cast, while delivering new single-player, multiplayer and co-operative gameplay.

Left 4 Dead 2 will be automatically updated with this free add-on. To celebrate this release, L4D2 and the 4-Pack will be 33% off until Monday.

About the update:

"The Passing" features 3 new maps, new weekly game modes (Mutations), a new "uncommon common" zombie class (the fallen survivor), melee weapon (golf club), firearm (M-60), support for infected bot play in Versus, 10 new achievements and more!

February 24, 2010 (2.0.1.1)

 * Fixed a Linux dedicated server crash.

February 19, 2010 (2.0.1.0)

 * Fixed all bot teams not leaving the starting area if sb_all_bot_team 1 was set.
 * Fixed a case where survivor bots would fail to rescue a friend from charger attacks.
 * Updated Thai translations.
 * Fixed an issue where servers wouldn't relist after the master server was bounced.
 * Fixed Charger jumping exploit.
 * Fixed Spitter bug where spit could emit from a location several inches from the head, causing the spit to unexpectedly strike nearby objects and fall.

February 5, 2010 (2.0.0.9)
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% )
 * Fixed a case where a player who dies, then is rescued from a rescue closet, and then is revived from a ledge hang receives the secondary weapon that 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 missing cs models/textures.
 * Added missing acunit01 model/texture
 * Added missing ammo_can_02 model/texture.
 * Added missing patio_chair model/texture.

January 12, 2010 (2.0.0.8)
Gameplay:
 * Fixed where last round of upgraded ammo didn't have upgrade effect.
 * Survivors driven by a Jockey now glows for infected team in all cases.
 * Fixed exploit that allowed Jockey players to get instant recharge of their ability.
 * Fixed Charger ability timer not resetting when killing a survivor with low health on their third strike.
 * Charger now applies a small amount of damage when charging through physic props.

Match Making:
 * Changed how requests are made to master server for group servers.
 * Fixed sorting on group servers UI.
 * Reduced update work on group servers UI.

Miscellaneous:
 * Made the water shader support splitscreen on the PC.
 * Miscellaneous fixes in the subtitles.
 * Updated system tray icon.
 * Fixed Survival timer issue caused when voting for round restart.

SDK/L4D2-LD/Hammer changes:
 * When browsing for a func_instance filename, the proper path relative to the current bsp will be returned. This allows level designers to use instances from the base game in dlc maps without having to manually fix up the filename.
 * Changed base.fgd default skybox to one that exists in L4D2.
 * Added env_instructor_hint to fgd, as well as content/game icon images.
 * Deadline URL fix.
 * Added missing vmt for env_instructor_hint.
 * L4D Addon Support - restored missing delivery van modified VMT.
 * L4D Addon Support - restored missing shelves metal 3.
 * L4D Addon Support - restored floodlight generator switch.
 * L4D Addon Support - restored missing airliner content.
 * Updated vbsp to correctly handle instances within instances.
 * Fixed the fullscreen engine changing the Hammer views, requiring a restart of Hammer.

December 18, 2009 (2.0.0.7)

 * Reduced Dedicated Server max search ping to 150 ms.
 * Teams that prefer listen servers will no longer be matched with teams that prefer dedicated servers.
 * Official dedicated servers are now preferred when searching for team matches.
 * More populous lobbies are now preferred over less populous ones when searching for games.
 * Players who crash or have failed to load are no longer banned if they have been kicked.
 * Update Russian subtitles.
 * Fixed not being able to interlink teams in team-on-team mode.
 * Fixed not being able to properly migrate team lobby after team leader would leave the lobby.
 * Fixed not being able to invite friends if player was not team leader in a team-on-team game.

December 12, 2009 (2.0.0.6)

 * Fixed players getting a bad spawn position after a level transition.

December 9, 2009 (2.0.0.5)

 * Changed rules for ghost placement in Scavenge Mode.
 * Player controlled Special Infected are no longer forced to un-crouch and lock strafe when they crouch attack.
 * Spitter spit that damages players on a moving elevator will now fizzle quickly.
 * Allowed the survivor and infected to rotate the camera view while being attacked by a Charger or Smoker.
 * Smoker that has dragged a survivor to the end now gets the same cinematic flashlight as the Hunter and Charger.
 * Fixed a crash in physics.
 * Updated the Charger's hit boxes.
 * Updated the Jockey's hit boxes.
 * Updated the Spitter's hit boxes.
 * Fixed player health on being revived after a Charger slam over a high ledge.
 * Fixed versus scores not resetting after a vote to change campaigns.
 * Fixed being able to use defibrillator on dead players who were far above or below you.
 * Fixed pink glow on dead survivors.
 * Fixed being able to hold crouch while incapacitated to get better weapon accuracy.
 * Fixed players pushing against some props causing them to accumulate downward velocity and then take falling damage when they let go of the forward key.
 * Fixed a case where an incapacitated survivor inside a rescue vehicle would trigger both the escape sequence and a round restart.
 * Fixed the helping hand from getting stuck when extended.

December 4, 2009 (2.0.0.4)

 * Fixed crash on startup when using FAT32 file system.
 * Fixed in-game chat input where the local encoding differs from the input language's.
 * Fixed bug where Survivor Bots would sometimes become unresponsive in Scavenge games.
 * Updated subtitle localization files for Hungarian, Portuguese, Romanian and Russian.
 * Fixed exploit that allowed players on the Infected team to spawn directly next to the Survivors.

December 1, 2009 (2.0.0.3)

 * Fixed case where game failed to launch in certain machine configurations.
 * Fixed bug where a burning witch could get into a state where she's invincible.
 * Fixed bug where bots would not shoot at Jockeys and Chargers while approaching to save a teammate.

November 27, 2009 (2.0.0.2)

 * Updated stats collection and related steam pages.
 * Fixed issue where players could be stuck if caught in charger pound.
 * Updated CPU detection.

November 21, 2009 (2.0.0.1)

 * Fixed performance problem when rendering lots of decals, notably when fighting tanks with shotguns.
 * Fixed rcon response not working on Linux dedicated servers.
 * Fixed matchmaking problem matching into Advanced and Expert games.
 * Fix bug that would cause other specials to try to pummel a player a Charger disconnects or reconnects.
 * Fixed versus mode results panel being cut off in transition stats screen in non-English.
 * Found games: fixed non-player entries drawing the wrong type of icon in the selected item name label.
 * Game mode selector on main menu now takes keyboard input.

November 17, 2009 (2.0.0.0a)

 * Fixed stability problem during level transition experienced by some users.