# Left 4 Dead 2 changelog > Set in the zombie apocalypse, Left 4 Dead 2 is a co-operative action horror FPS takes you and your friends through the cities,… - Vendor: Valve - Category: Games - Official site: http://www.l4d.com - Tracked by: What's New (https://whatsnew.fyi/product/left-4-dead-2) - Harvested from: Steam (app 550) - Entries below: 25 of 30 (newest first; the rest are on https://whatsnew.fyi/product/left-4-dead-2) What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog. ## Releases ### Left 4 Dead 2 - Update - Date: 2026-06-30 - Original notes: https://store.steampowered.com/news/app/550/view/687509549434800452 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-687509549434800452 - **security** — Apply latest security patches to Linux build - **changed** — Revise fix for Linux build An update has been released for Left 4 Dead 2. - Revised fix for Linux build including latest security patches. ### Left 4 Dead 2 - Update - Date: 2026-06-26 - Original notes: https://store.steampowered.com/news/app/550/view/687509549434799120 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-687509549434799120 - **fixed** — several crashes and exploits reported via HackerOne An update has been released for Left 4 Dead 2. - Fixed several crashes and exploits reported via HackerOne. ### Left 4 Dead 2 - Update - Date: 2025-02-05 - Original notes: https://store.steampowered.com/news/app/550/view/521956605068050680 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-521956605068050680 - **fixed** — Fixed a compatibility issue that was causing a crash on Linux clients An update has been released for Left 4 Dead 2. - Fixed a compatibility issue that was causing a crash on Linux clients. ### Left 4 Dead 2 - Update - Date: 2025-01-17 - Original notes: https://store.steampowered.com/news/app/550/view/626663655055818919 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-626663655055818919 - **fixed** — Fixed exploits used to crash remote servers An update has been released for Left 4 Dead 2. - Fixed exploits used to crash remote servers. ### Left 4 Dead 2 - Update - Date: 2024-12-02 - Original notes: https://store.steampowered.com/news/app/550/view/4478362535967327379 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4478362535967327379 - **fixed** — Fixed some exploits used to crash remote servers An update has been released for Left 4 Dead 2. - Fixed some exploits used to crash remote servers. ### Left 4 Dead 2 - Update - Date: 2024-10-24 - Original notes: https://store.steampowered.com/news/app/550/view/4538032056440979617 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4538032056440979617 - **security** — Fixed several crash and remote code execution exploits - **fixed** — Fixed a crash on some NVIDIA graphics cards when shader detail is set to High An update has been released for Left 4 Dead 2. - Fixed several crash and remote code execution exploits. - Fixed a crash on some NVIDIA graphics cards when shader detail is set to High. ### Left 4 Dead 2 - Update - Date: 2024-07-26 - Original notes: https://store.steampowered.com/news/app/550/view/4352250327663410166 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4352250327663410166 - **security** — Player connect message is no longer networked to clients to prevent exposing player IP addresses An update has been released for Left 4 Dead 2. - Player connect message is no longer networked to clients, to prevent exposing player IP addresses. ### Left 4 Dead 2 - Update - Date: 2024-06-26 - Original notes: https://store.steampowered.com/news/app/550/view/4255420398661517980 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4255420398661517980 - **fixed** — Fixed a regression that blocked taking screenshots An update has been released for Left 4 Dead 2: - Fixed a regression that blocked taking screenshots. ### Left 4 Dead 2 - Update - Date: 2024-06-25 - Original notes: https://store.steampowered.com/news/app/550/view/4192369369678526786 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4192369369678526786 - **fixed** — Memory leak exploit in lobby chat - **security** — Prevent running arbitrary script code on a remote server - **security** — Prevent a network exploit that gave the client access to server settings - **added** — Implementation example for a new beta feature in Steam An update has been released for Left 4 Dead 2: - Fixed a memory leak exploit in lobby chat. - Prevent running arbitrary script code on a remote server. - Prevent a network exploit that gave the client access to server settings. - Implementation example for a new beta feature in Steam. ### Left 4 Dead 2 - Update - Date: 2024-06-04 - Original notes: https://store.steampowered.com/news/app/550/view/4185612701673745271 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4185612701673745271 - **fixed** — An exploit that could block a player from connecting to any game, whether online or local - **fixed** — Two exploits that used invalid content to crash the game or prevent it from loading - **fixed** — A memory leak when rejecting invalid content An update has been released for Left 4 Dead 2: - Fixed an exploit that could block a player from connecting to any game, whether online or local. - Fixed two exploits that used invalid content to crash the game or prevent it from loading. - Fixed a memory leak when rejecting invalid content. ### Left 4 Dead 2 - Update - Date: 2024-05-26 - Original notes: https://store.steampowered.com/news/app/550/view/4168722935772243545 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4168722935772243545 - **fixed** — Fixed a bug that prevented the community server list from appearing An update has been released for Left 4 Dead 2: - Fixed a bug that prevented the community server list from appearing. ### Left 4 Dead 2 - Update - Date: 2024-05-14 - Original notes: https://store.steampowered.com/news/app/550/view/4186736071078420633 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4186736071078420633 - **security** — Fix two exploits that could remotely crash servers - **fixed** — Fix music not playing at the main menu on Linux An update has been released for Left 4 Dead 2: - Fixed two exploits that could remotely crash servers. - Fixed music not playing at the main menu on Linux. ### Left 4 Dead 2 - Update - Date: 2024-04-23 - Original notes: https://store.steampowered.com/news/app/550/view/4213755760606354384 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4213755760606354384 - **security** — Fixed an exploit where malicious network packets could severely degrade server performance - **security** — Fixed a client exploit that could cause long server stalls - **fixed** — Fixed a potential crash if a Charger failed to return to valid nav for an extended period of time - **fixed** — Fixed a rare hang from ray traces encountering NaN values An update has been released for Left 4 Dead 2: - Fixed another exploit where malicious network packets could severely degrade server performance. - Fixed a client exploit that could cause long server stalls. - Fixed a potential crash if a Charger failed to return to valid nav for an extended period of time. - Fixed a rare hang from ray traces encountering NaN values. ### Left 4 Dead 2 - Update - Date: 2024-04-12 - Original notes: https://store.steampowered.com/news/app/550/view/6658083997556345850 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-6658083997556345850 - **security** — Blocked an exploit that could forcibly disconnect a player from any server, even when playing a local game An update has been released for Left 4 Dead 2: - Blocked an exploit that could forcibly disconnect a player from any server, even when playing a local game. ### Left 4 Dead 2 - Update - Date: 2024-03-26 - Original notes: https://store.steampowered.com/news/app/550/view/4103415032728534407 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4103415032728534407 - **fixed** — Fixed two exploits that could crash remote servers - **fixed** — Fixed missing lobby state messages - **fixed** — Fixed community server searches not always returning the full set of lowest-ping results An update has been released for Left 4 Dead 2: - Fixed two exploits that could crash remote servers. - Fixed missing lobby state messages. - Fixed community server searches not always returning the full set of lowest-ping results. ### Left 4 Dead 2 - Update - Date: 2024-03-13 - Original notes: https://store.steampowered.com/news/app/550/view/4121428800362167585 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4121428800362167585 - **changed** — Improved the reliability of mm_dedicated_force_official_servers to find the lowest ping server across the supplied IPs An update has been released for Left 4 Dead 2: - Improved the reliability of "mm_dedicated_force_official_servers" to find the lowest ping server across the supplied IPs. ### Left 4 Dead 2 - Update - Date: 2024-03-11 - Original notes: https://store.steampowered.com/news/app/550/view/4121428166613667501 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4121428166613667501 - **fixed** — Fixed several matchmaking lobby exploits - **changed** — The cvar mm_dedicated_force_servers now only applies to lobbies with the Best Available Dedicated server type as originally intended - **added** — Added new cvar mm_dedicated_force_official_servers for forcing official dedicated server selection An update has been released for Left 4 Dead 2: - Fixed several matchmaking lobby exploits. - The cvar "mm_dedicated_force_servers" now only applies to lobbies with the "Best Available Dedicated" server type as originally intended - for all other lobby types the cvar is ignored. Lobby leaders who wish to force official dedicated server selection due to location or network issues should use the new cvar "mm_dedicated_force_official_servers", which only pulls from available official dedicated servers at the requested IPs. ### Left 4 Dead 2 - Update - Date: 2024-02-29 - Original notes: https://store.steampowered.com/news/app/550/view/4111294434899099665 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4111294434899099665 - **fixed** — Fixed an exploit where reliable network fragments could stall out a server indefinitely - **changed** — Re-enabled uploads by default so sprays will work again An update has been released for Left 4 Dead 2: - Fixed an exploit where reliable network fragments could stall out a server indefinitely. - Re-enabled uploads by default so sprays will work again. ### Left 4 Dead 2 - Update - Date: 2024-02-22 - Original notes: https://store.steampowered.com/news/app/550/view/4179973693296412157 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4179973693296412157 - **fixed** — Fixed a degenerate case where malformed network packets could delay processing the remainder of the stream, severely impacting server performance An update has been released for Left 4 Dead 2: - Fixed a degenerate case where malformed network packets could delay processing the remainder of the stream, severely impacting server performance. ### Left 4 Dead 2 - Update - Date: 2024-02-21 - Original notes: https://store.steampowered.com/news/app/550/view/4179973693289710072 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4179973693289710072 - **fixed** — Fixed possible corruption of the unreliable network stream during high network loads - **changed** — Increased default command limits to prevent spurious disconnects An update has been released for Left 4 Dead 2: - Fixed possible corruption of the unreliable network stream during high network loads. - Increased default command limits to prevent spurious disconnects. ### Left 4 Dead 2 - Update - Date: 2024-02-07 - Original notes: https://store.steampowered.com/news/app/550/view/4014465139622194025 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-4014465139622194025 - **security** — Add protections against malformed network packets - **changed** — Reduce server-side command limits per client - **fixed** — Fix a regression in script handling of regular expressions - **security** — Fix several vulnerabilities and exploits reported via HackerOne An update has been released for Left 4 Dead 2. - Added protections against malformed network packets. - Reduced server-side command limits per client. - Fixed a regression in script handling of regular expressions. - Fixed several vulnerabilities and exploits reported via HackerOne. ### Left 4 Dead 2 - Update - Date: 2024-01-17 - Original notes: https://store.steampowered.com/news/app/550/view/3955916441765458302 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-3955916441765458302 - **security** — Fixed several vulnerabilities and exploits reported via HackerOne An update has been released for Left 4 Dead 2: - Fixed several vulnerabilities and exploits reported via HackerOne. ### Left 4 Dead 2 - Update - Date: 2023-08-31 - Original notes: https://store.steampowered.com/news/app/550/view/3649658979104139653 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-3649658979104139653 - **removed** — Removed auto-revive from Tank Run mutation - **changed** — Re-enabled water slowdown in Tank Run mutation - **changed** — Re-enabled crawling when incapped in Tank Run mutation - **changed** — Lowered revive health to 40 in Tank Run mutation - **changed** — Set revive duration to 3 seconds in Tank Run mutation - **fixed** — Fixed issue where Tanks deleted by triggers were still counted as alive - **changed** — Starting the two extra generators in Sacrifice finale will now decrease the finale timer by 30 seconds and spawn a Tank for each generator - **fixed** — Fixed issue where Tanks wouldn't spawn if some players were still connecting An update has been released for Left 4 Dead 2. Tank Run mutation fixes based on feedback from Tank Run community groups: - Removed auto-revive. - Re-enabled water slowdown. - Re-enabled crawling when incapped. - Lowered revive health to 40. - Revive duration set to 3 seconds. - Fixed issue where Tanks deleted by triggers were still counted as alive. - Starting the two extra generators in Sacrifice finale will now decrease the finale timer by 30 seconds and spawn a Tank for each generator. - Fixed issue where Tanks wouldn't spawn if some players were still connecting. ### Update - Left 4 Dead 2 - Date: 2023-08-22 - Original notes: https://store.steampowered.com/news/app/550/view/3646280012042428636 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-3646280012042428636 - **fixed** — Fixed several exploits reported via HackerOne - **fixed** — Fixed controller navigation in some menus - **fixed** — Fixed not being able to open the train door in Crash Course when playing the Tank Run Mutation - **changed** — Only the original attacker gets credited for damage caused by exploding props - **changed** — Restored the knife's original horizontal swing trajectory - **fixed** — Fixed incorrect instructor lesson bindings for the Tank - **fixed** — Fixed LDR skybox rendering on low shader settings - **added** — Added new script functions AreAllSurvivorsInBattlefield, GetClosestCharacterWhoIsIT, GetClosestSurvivor, GetHighestFlowSurvivor, GetLowestFlowSurvivor, and GetRandomSurvivor - **added** — Added new response criteria TankActive and Chapter for script responses - **fixed** — Fixed numerous stuck spots across multiple maps in various game modes - **changed** — Restored window clip-hang bugs in Dead Center Map 1 to re-allow access to the rooftop in Coop mode - **changed** — Tank will now only spawn after Survivors have exited the elevator in Dead Center Map 1 Versus mode - **fixed** — Fixed issues with THE MAIN ATTRACTION Achievement in Dark Carnival Map 5 by adding more triggers - **changed** — Named the TLS Swamp gator Fred in Swamp Fever Map 1 - **changed** — Restored a shortcut in Hard Rain Map 2 and fixed the soft-lock where Survivors cannot progress if one player skipped the elevator - **changed** — Reduced jet strike trigger damage after the balcony drop in The Parish Map 4 Versus mode from 25 damage per touch to 2 damage per touch - **changed** — All sets of railings in No Mercy Map 2 will now appear for all players regardless of graphics settings - **changed** — Simplified The Last Stand Map 2 finale difficulty scaling to only increase on Advanced and Expert difficulties - **changed** — Lowered the number of required gas cans in The Last Stand Single Player by 25 percent An update has been released for Left 4 Dead 2. - Fixed several exploits reported via HackerOne. - Fixed controller navigation in some menus. - Fixed not being able to open the train door in Crash Course when playing the Tank Run Mutation. - Only the original attacker gets credited for damage caused by exploding props. - Restored the knife's original horizontal swing trajectory. - Fixed incorrect instructor lesson bindings for the Tank. - Fixed LDR skybox rendering on low shader settings. New response criteria: - "TankActive"- 0 means no Tank aggro, 1 means Tank is aggro. - "Chapter" - 0 is first map of mission. New Script Functions: - "AreAllSurvivorsInBattlefield" - Returns true if all Survivors are in the battlefield - "GetClosestCharacterWhoIsIT" - Returns the closest character who is IT - "GetClosestSurvivor" - Returns the closest Survivor to the passed origin - "GetHighestFlowSurvivor" - Returns the Survivor with the highest flow - "GetLowestFlowSurvivor" - Returns the Survivor with the lowest flow - "GetRandomSurvivor" - Returns a random Survivor Maps and Mutations: Dead Center Map 1:  - Restored window clip-hang bugs that were patched with TLS to re-allow access to the rooftop in Coop mode.  - Versus: Tank will now only spawn after Survivors have exited the elevator, and no later than leaving the kitchen. Map 3:  - Blocked a stuck spot at vending machine alternative path. Dark Carnival Map 1:  - Patched a rarer stuck spot at the swamp's cargo container.  - Patched an elaborate SI out of bounds exploit. Map 5:  - Addressed some issues with "THE MAIN ATTRACTION" Achievement by adding more triggers so it no longer fails if any Survivor disconnects or goes idle while on stage. Swamp Fever Map 1:  - Patched janky ladder near the ferry event.  - By popular community request the TLS Swamp gator is now canonically named Fred. Map 2:  - Blocked a stuck spot behind some rocks at the start near the parachutist.  - Blocked a stuck spot on a cypress knee near the parachutist area dock. Map 3:  - Blocked stuck spots at two sets of cypress knees around the event start area.  - Versus: Blocked a stuck spot for SI behind a bush to the left of the first bridge upon entering the water.  - Versus: Blocked a stuck spot for SI in the bush near the lantern/event start.  - Versus: Improve SI clipping of first ladder outside saferoom to allow drop through a large gap.  - Versus: Moved a TLS Infected ladder out of the Survivor's way at the start. Map 4:  - Versus: Blocked a stuck spot for SI behind a bush in the back of the enclosed hedge area. Hard Rain Map 2:  - Restored a shortcut that was patched with TLS; instead fixed the soft-lock where Survivors cannot progress if one player skipped the elevator. The Parish Map 2:  - Eliminate a stuck spot that a previous ladder patch created. Map 3:  - Versus: New ladder in far corner of manhole drop area to fix stuck . Map 4:  - Versus: Reduced a jet strike trigger after the balcony drop that previously dealt 25 damage per touch (75 total) to Survivors, down to only 2 damage per touch to behave like the other triggers. The Passing Map 1:  - Blocked a stuck spot in a corner behind a floodlight in the top floor after the alarm cars. Map 2:  - Fixed collision issue with clips on the stairs by the saferoom that caused noticeable teleporting when not on a local server. The Sacrifice Map 2:  - Versus: Delete func clip that blocks SI access into end closet. No Mercy Map 1:  - Lift anti-grief kill trigger off the ground to prevent an incap glitch.  - Versus: Add clip to patch a ladder shortcut at the start. Map 2:  - All sets of railings will now appear for all players regardless of graphics settings. Crash Course Map 1:  - Block rare stuck spot between the box wreck and traffic light. Map 2:  - Clip to prevent gas cans from falling between finale buses. Death Toll Map 3:  - Blocked a stuck spot at the top of a rock cliff cluster just after the church bus.  - Blocked a stuck spot between the clif _[Truncated at 4000 characters — full notes: https://store.steampowered.com/news/app/550/view/3646280012042428636]_ ### Left 4 Dead 2 - Update - Date: 2023-05-19 - Original notes: https://store.steampowered.com/news/app/550/view/3712699861433828965 - Permalink: https://whatsnew.fyi/product/left-4-dead-2/releases/steam-3712699861433828965 - **fixed** — Console chat regression from previous update An update has been released for Left 4 Dead 2. - Fixed console chat regression from previous update.