Latest
Oct 27 · 42.22 pre-release: ladders and crowbar break-insOct 23 · First-person mods are not officially supportedOct 21 · The Indie Stone on Java mods: download responsiblySep 28 · Build 42.21 Stable: zombie duplication fixesAug 26 · Security fixes on every branchAug 17 · Servers now handle up to 254 playersJul 29 · Build 42 goes Stable

Project Zomboid patch notes

Every Build 42 update of 2026, newest first, in plain English: the Stable releases since July 29, then the Unstable builds that led up to them. We keep the parts that change how you play, host or mod, and link the official notes for the full list. Current Stable: 42.21.

27Oct

Build 42.22 Pre-Release: “Moving on Up”

Pre-Release · October 27, 2026

The first build on the new Pre-Release branch, which replaces Unstable. Pre-Release builds stay up at least one week before going Stable. Back up long-term saves before trying it. Stable is still 42.21.

New

  • Ladders around the map can be climbed with E or the context menu. Zombies cannot climb them.
  • Crowbars force locked doors, windows, garage doors and gates. Strength helps; failures can damage the crowbar. Burglars are faster and quieter. Security doors and jail cells cannot be forced.

Changes

  • You can push with both hands full; items that block pushing are dropped.
  • No sleeping while the Bad Smell moodle is active.
  • Ammo boxes can be opened while walking.
  • XXL trees render better and block less while driving.

Fixes

  • Animals dying when a cell unloads; rabbit kits starving when the mother has no milk; chickens vanishing from full hutches.

Multiplayer

  • PvP damage is now calculated on the server.
  • Duplicate and cloned characters fixed; faster server backups.
  • Trailer physics and towing desync fixed; map notes and the All Known on Start option save again; anti-cheat updated.
Pre-ReleaseLaddersOfficial notes on Steam »
28Sep

Build 42.21 Stable

Stable · September 28, 2026

The first incremental update after Build 42 is now live for everyone. It spent five days on Unstable and testers reported no major problems. From now on, every update goes to Unstable first, then Stable.

Zombies

  • Zombies no longer vanish when you leave an area and come back, in single player and multiplayer.
  • The worst zombie duplication bugs in multiplayer are fixed. A few cases remain and are due in the next update.

XXL trees

  • Giant trees cut away better while you drive.
  • They no longer hide houses and furniture underneath them.
  • They are more see-through overall. More work is planned.

Modders and server admins

  • The loadstring and loadstream Lua functions, removed in 42.20.4, are back.

Thanks

  • The Indie Stone credited Scribl (Boris) and Rasmus Moorats (nnsee) for reporting the security holes fixed in 42.20.4.
StableFixesOfficial notes on Steam »
23Sep

Build 42.21 Unstable: "Re-population of the Dead"

Unstable · September 23, 2026

The test version of 42.21, with the full list of smaller changes that later went Stable. Back up your save before testing an existing world on Unstable.

Quality of survival

  • Characters re-equip items automatically after exercising.
  • The in-game map is more accurate while exploring.
  • Pathfinding avoids trampling your crops where it can.
  • Welders now start with Welding recipes instead of Blacksmithing.
  • 86 more fluid containers can purify water in the right oven.
  • Washing machines clean dirty rags, strips and bandages.
  • Fridges and freezers warm up gradually on the day the power goes out, and food in a bag inside a fridge now stays cold.
  • Antibiotics can be packed in boxes.
  • Explosives now work in basements.

Split-screen

  • Read-book status and XP boosts are no longer shared between players.
  • Fishing works properly.
  • Fixed a crash when two players shared a moving vehicle.

Multiplayer

  • Anti-cheat covers more cheats, and safehouse exploits are closed.
  • The server browser shows the last wipe, not the last restart.
  • You get a warning when joining a server on a different game version.
  • Driving at high ping (around 150 ms and up) is smoother: fewer unloaded roads, teleporting passengers and judder.
  • Fixed a height-level desync between players.

Security

  • Fixed a hole that let players join dedicated servers without proper Steam login, which got around SteamID bans.
UnstableMultiplayerSecurityOfficial notes on Steam »
26Aug

Hotfixes: 42.20.4 Stable, 42.19.2 Unstable, 41.78.21 Legacy

All branches · August 26, 2026

A security patch for every branch at once. It should not break saves.

Security

  • Fixed security vulnerabilities on Stable, Unstable and Legacy.

Modders

  • loadstring and loadstream were removed. Mods that used them had to change (both came back in 42.21).
SecurityLegacy B41Official notes on Steam »
17Aug

42.20.3 Stable hotfix

Stable · August 17, 2026

Bigger servers and fewer memory problems.

Multiplayer

  • Servers handle player limits better, up to 254 players, and admins can still get in when a server is full.
  • Fixed the game hanging forever on "Loading Map".

Fixes

  • Several memory leaks fixed that slowed the game down and caused crashes over time, plus extra memory savings.
  • Fewer black and grey boxes when travelling fast through the world.
  • Fixed errors during lighting updates.
MultiplayerPerformanceOfficial notes on Steam »
05Aug

42.20.2 Stable hotfix

Stable · August 5, 2026

A small technical fix, mostly for mod makers.

Modders

  • Percent signs in files are handled properly again. Mods should use %% to show a % sign; a temporary workaround will be removed in a later update.
  • Error logs now point out text that needs updating.

Fixes

  • Quick tips no longer show % as %%.
  • Memory info added to the FPS debug display.
ModdingOfficial notes on Steam »
05Aug

42.20.1 Stable hotfix

Stable · August 5, 2026

The first fix-up after Build 42 went Stable, aimed at busy servers.

Multiplayer

  • Much less lag on high-population servers, from a fix to how map chunks unload.
  • Stronger Lua checksum checks for anti-cheat.
  • Vehicles no longer disappear when another player disconnects.
  • Broken Build 41 worlds can no longer be hosted on Build 42 servers.
  • Fixed crashes in the Multiplayer menu with some languages, and a missing menu for players coming from Build 41.

Fixes

  • Fixed a memory leak and reduced memory use.

Modders

  • Mods can now write .json files.
MultiplayerPerformanceOfficial notes on Steam »
29Jul

Build 42.20.0: Build 42 goes Stable

Stable · July 29, 2026

The day Build 42 became the default version of the game. These are the changes from 42.19 to 42.20; Build 41 stays playable on the legacy41 branch (Steam → Properties → Game Versions & Betas).

New

  • Map Glowup: many areas overhauled with new tiles, buildings and locations.
  • XL and XXL trees added to the world. They drop more wood, and you can hide their overhang with right-click while driving.
  • Challenges: "28 Minutes Later" and "Top of the World" replace "Cabin in the Woods".
  • New main menu artwork, plus search boxes in the Discovered Recipes and Media screens.

Balance

  • More meat from large animals with the butcher hook.
  • Towing reworked: trailers can now come loose on sharp, fast turns.
  • The "zombie count before deletion" sandbox limit rises from 500 to 5,000.

Multiplayer

  • Anti-cheat reworked and switched back on, with better logging.
  • Faster loading after "Click to Start", and big stacks of items move much faster.
  • Ping shown for each player, and a server option to show or hide coordinates.
  • Many exploits closed, including ways to spawn items or gain XP illegitimately.
  • A long list of desync fixes for zombies, players, corpses, vehicles and trading.

Fixes

  • Fixed hypothermia killing players too fast.
  • Fixed lights not using generator power.
  • Fixed point-blank shots missing.
  • Fixed a rare crash on certain AMD graphics cards and a crash on macOS.
  • Fixed desktop icons not appearing on Linux and Mac.

Controller and sound

  • Better controller support across trading, crafting, crops and menus.
  • New sound effects for welding, sawing and packing, and fixed voice chat cutting out under heavy sound.

Security

  • A security patch for Builds 41 and 42.19, credited to Jorge Escabias.
Build 42MajorOfficial notes on Steam »
Before Stable: Build 42 on the Unstable branch
01Jun

Build 42.19.0 Unstable

Unstable · June 1, 2026

The last big Unstable update before Build 42 went Stable.

New

  • Controller remapping with a new gamepad customization screen.
  • Extended idle animations when sitting on the floor.

Balance

  • Hunter now starts with +1 Tracking instead of +1 Trapping; Hiker costs -5 instead of -6.
  • Weaving a fabric roll now takes 400 thread instead of 100.
  • The Discomfort moodle has a new colour so it is easier to tell apart from Unhappy.

Multiplayer

  • More anti-cheats switched on: command line, safehouse, XP and permissions.
  • IP bans are back for direct connections on Steam servers.
  • Fixed magazines vanishing after reloading, endless-endurance and map-download exploits, and item duplication.

Controller fixes

  • Many fixes across the spawn picker, load screen, crafting stations and world map.
UnstableControllerOfficial notes on Steam »
11May

Build 42.18.0 Unstable

Unstable · May 11, 2026

A modding and multiplayer polish update.

New

  • Reload animations for lever-action rifles and shotguns.
  • Option to pause the game automatically while reading maps.
  • A keybind to sit on the ground.

Balance

  • Park Ranger gains +1 Carving instead of +1 Tracking; Rancher gains +1 Fitness instead of +1 Agriculture.
  • Improvised gas masks reworked: clean rags now work as filters.
  • Bigger water containers: jerry can 20 L, canteen 900 mL, hydration backpack 2 to 3 L.

Modding

  • Recipes from mods now work in multiplayer, with new functions for recipes, traits and factions.

Multiplayer

  • Better sound for distant events and fixes for vehicles hitting players.
UnstableModdingOfficial notes on Steam »
20Apr

Build 42.17.0 Unstable

Unstable · April 20, 2026

More places to start and a round of game-mode tuning.

New

  • Sandbox games can start in Brandenburg, Echo Creek, Ekron, Fallas Lake, Irvington, March Ridge or Valley Station. Occupation spawns stay limited to the four classic towns.
  • Skill VHS tapes for Aiming, Animal Care, Blacksmithing, Electrical, First Aid, Knapping, Pottery, Tailoring and Welding.
  • An updated in-game Survival Guide and a credits screen.

Game modes

  • Infected wounds now hurt in every mode.
  • More cars spawn with fuel in Apocalypse, and more general loot in Apocalypse, Outbreak and Rising.

Occupations and traits

  • Cheaper Doctor, Nurse, Rancher, Electrician and Welder; DIY Expert now gives the Inventive trait.
  • Farmer gains +1 Strength; Chef now uses Short Blade, not Short Blunt.
  • Smoker now gives 3 points, High Thirst 2, and Nutritionist costs 2.

Animals

  • Animals stress out less from zombies, rain and noise, and calm down more when petted.
UnstableBalanceOfficial notes on Steam »
31Mar

Build 42.16 Unstable (and hotfixes .1 to .3)

Unstable · March 31 to April 8, 2026

The big occupations and traits rework. Saves from 42.15 and earlier do not carry over.

Occupations

  • Most jobs now start with more skill, so they feel like professionals rather than apprentices.
  • Fire Officer is renamed Firefighter, and Angler is renamed Fishing Guide.

Traits

  • New traits: Tinkerer (+1 Maintenance) and Target Shooter (+1 Aiming).
  • Wilderness Knowledge is renamed Bushcrafter.
  • Cat's Eyes and Wakeful cost more; First Aider and Iron Gut cost less.
  • Desensitized now also blocks Discomfort.

Game modes

  • Extinction sprinters now run in daylight too.
  • Slower world erosion in Apocalypse, Outbreak and Rising.

Tailoring and guns

  • Tailoring XP now rewards crafting items, not grinding patches.
  • New weapon attachment models and several firearm capacity fixes.

Security (April 8)

  • 42.16.3 and Build 41 (41.78.19) patched security holes, the same day malicious Workshop mods were removed.
UnstableBalanceSecurityOfficial notes on Steam »
09Mar

Build 42.15 Unstable (and hotfixes .1 and .2)

Unstable · March 9 to 11, 2026

New game modes and new guns.

Game modes

  • Apocalypse becomes the lore-canon mode, with no zombie respawn, more firearms and firearm jamming.
  • Outbreak for faster progress, Rising for cozy building, and Extinction with sprinters for veterans.
  • Each mode has a matching preset in Custom Sandbox.

New firearms

  • JS-14 rifle, JS-3T tactical shotgun, L92 carbine, L94 rifle, MSR7T tactical rifle and Trapper carbine, with reworked gun loot.

Quality of life

  • Reading is faster when sitting down.
  • Shift-click to select several items in workstation menus.

Hotfixes

  • Fixed the game not loading for usernames with non-English characters, and animals on a rope not moving.
UnstableMajorOfficial notes on Steam »