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Project Zomboid
Zombie Survival · Isometric · The Indie Stone
Project Zomboid Build 42 Server Setup (Multiplayer)
How to create a Project Zomboid Build 42 server: B42 multiplayer at RespawnHost or self-hosted (app ID 380870, unstable beta) — status, B41 comparison, tips.
Last updated July 20, 2026 · RespawnHost
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Build 42 multiplayer: where things stand
Build 42 multiplayer has been available since December 11, 2025 — but only on the unstable branch. As of July 2026, the current unstable version is 42.19, while the stable branch remains 41.78.16. At RespawnHost, a B42 server is up in minutes; for self-hosting you need the dedicated server app 380870 with the unstable beta branch.
Is Build 42 multiplayer stable yet?
No. B42 MP is officially work in progress:
| Milestone | Date / status |
|---|---|
| B42 unstable (singleplayer) | December 17, 2024 |
| B42 multiplayer | December 11, 2025 with unstable 42.13 (older B42 saves incompatible) |
| Current unstable version | 42.19 (as of July 2026) |
| Stable branch | still 41.78.16 |
| Stable candidate | 42.20 — “later this summer” according to The Indie Stone |
| Planned afterwards | ”Build 42 Support Update” (rest of 2026) |
Warning
The Indie Stone's official recommendations for B42 multiplayer: fewer than 20 players, start without mods and disable ragdolls in MP. Expect bugs on the unstable branch — take regular backups.
B41 or B42 — which version for your server?
| Build 41 (41.78.16) | Build 42 (unstable) | |
|---|---|---|
| Status | Stable, battle-tested | Unstable, officially WIP |
| Multiplayer | mature | since Dec 11, 2025, in development |
| World | 8 height levels | Basements + 32 height levels, new towns (Brandenburg, Ekron, Irvington, Echo Creek) |
| Animals | — | Ranching (chickens, cows, sheep, pigs) + hunting (deer, rabbits, rats) |
| Crafting | base system | Overhaul: blacksmithing, pottery, brewing and more |
| Save games | — | B41 worlds are incompatible with B42 |
In short: If you want maximum stability and the full mod selection, stick with B41. If you want the new features and can live with bugs, go B42 — ideally with a small group.
How do you create a B42 server at RespawnHost?
- Rent a Project Zomboid Server — fixed package or pay-per-use, the server is online in under 90 seconds.
- Pick a package based on player count — see the How much RAM? guide.
- Enable Build 42: In the panel, switch the game version to the B42 unstable branch under configuration (default is the B41 stable branch).
- Start the server and connect: You’ll find IP and port in the panel — in the game, enter the IP and port 16261 under Join. Basics like password, PVP and slots are configured in servertest.ini.
How do you self-host (SteamCMD)?
The dedicated server uses app ID 380870. You install Build 42 via the unstable beta branch:
steamcmd +login anonymous +app_update 380870 -beta unstable validate +quit- Start:
StartServer64.bat(Windows) orstart-server.sh(Linux) - Configs:
%USERPROFILE%\Zomboid\Server\(Windows) or~/Zomboid/Server/(Linux) — this is whereservertest.iniandservertest_SandboxVars.lualive - RAM: allocated as a Java parameter via
-Xmxin the start script - Port: open
16261(UDP) — the range 16261–16262 is used
What do we recommend for a B42 launch?
- Start small: stay under 20 players (official recommendation)
- Launch without mods and add them gradually once the server runs stable — see server settings
- Plan for backups: unstable updates can cause problems — at RespawnHost, take a panel backup before every update
- Set your sandbox up front: zombies, loot and XP are covered in the sandbox settings guide
Frequently asked questions
When will Build 42 go stable? Version 42.20 is the stable candidate — “later this summer” according to The Indie Stone (as of July 2026). A “Build 42 Support Update” is planned for the rest of 2026 afterwards.
Can I bring my B41 world to B42? No — B41 worlds are incompatible with Build 42. You start a fresh world for B42.
Is Project Zomboid available on consoles or with crossplay? No. Project Zomboid is PC-only — Windows, macOS and Linux play together, and there is no console release.
Do mods work in B42 multiplayer? In principle yes (Workshop support), but The Indie Stone recommends launching B42 servers without mods. How to add mods is covered in the server settings guide.
Related guides
- Server settings (servertest.ini) — PVP, whitelist, mods & ports
- Sandbox settings — zombies, loot & XP
- Admin commands — becoming admin & managing the server
- How much RAM? — finding the right package