Project Zomboid multiplayer works in the stable Build 42 branch since July 29, 2026, when The Indie Stone released 42.20 to the public branch on Steam. Everyone on stable plays on Build 42, servers are limited by their own player cap (up to 254 players since the 42.20.3 hotfix), and anyone who wants Build 41 has to switch to the legacy41 beta branch. The one rule that decides who you can play with: you and your group must be on the same build.
We checked The Indie Stone's Steam announcements and the Steam store data on November 2, 2026. The official posts do not describe every step of hosting a server, so where a detail is not in them, we leave it out rather than guess.
Quick facts
| Topic | What we found |
|---|---|
| Developer | The Indie Stone |
| Platform | PC on Steam (Windows, macOS, Linux) |
| Price | $24.99 on Steam (US), November 2, 2026 |
| Build 42 on stable | 42.20, released July 29, 2026 |
| Latest stable | 42.21, released September 28, 2026 |
| Player cap per server | Up to 254 players, supported since the 42.20.3 hotfix (August 17, 2026) |
| Build 41 | Still available through the legacy41 beta branch in Steam |
| Build 41 saves | Not compatible with Build 42 |
| Same-screen play | Split-screen co-op is listed on the Steam page |
| Mods | Steam Workshop; only Lua mods are officially supported |
What changed with Build 42 stable
Build 42 spent a long time in the Unstable beta before it reached everyone. The Indie Stone announced on its Steam news feed that 42.20 would land on the stable public branch on Wednesday, July 29, 2026, and the 42.20.0 release did exactly that. Multiplayer ships as part of it: the patch notes list a reworked and re-enabled anti-cheat, faster stackable item transfers, ping values in player lists and many desync, trading and exploit fixes.
Hotfixes followed quickly, and several matter for multiplayer:
- 42.20.1 (August 5, 2026) improved Lua checksum validation for anti-cheat, fixed severe chunk unloading lag on busy servers and blocked broken Build 41 worlds from being hosted on Build 42 servers.
- 42.20.3 (August 17, 2026) added support for up to 254 players and administrator access when a server is full.
- 42.21 (September 28, 2026) went through Unstable first and fixed zombie duplication in multiplayer, plus zombies vanishing when a player leaves and re-enters a chunk.
On October 27, 2026, The Indie Stone replaced the Unstable branch with a new Pre-Release branch: each update now stays there for at least one week before it reaches Stable. 42.22 is in Pre-Release as of November 2, 2026, with more multiplayer fixes, so it is not stable yet.
Build 42 or Build 41 (legacy41)
A server runs one build, so a Build 42 player and a Build 41 player cannot share a world. The Indie Stone states that Build 41 savegames are not compatible with Build 42, and the 42.20.1 fix blocking broken Build 41 worlds on Build 42 servers points the same way.
To go back to Build 41, the official instructions are:
- Right-click Project Zomboid in your Steam library.
- Select "Properties".
- Under "Game Version & Betas", select "legacy41".
The legacy branch still gets security hotfixes: 41.78.21 shipped on August 26, 2026. Server owners who stay on Build 41 should tell their players to opt in to the same branch. Everybody else gets Build 42 by default.
Ways to play with others
The Steam page lists online co-op, online PvP and shared/split-screen co-op, so there are three setups worth knowing:
| Setup | Good for | Watch out for |
|---|---|---|
| Dedicated server | A persistent world, large groups, admins and rules | Someone has to run it, update it and keep it online |
| Public server | Joining a community with regulars, no setup | Each server has its own rules, wipes and mod list |
| Split-screen co-op | Two people on one PC, with a controller | The Indie Stone calls the split-screen audience small |
Dedicated servers received specific fixes in Build 42, including a startup exception fix in 42.20.0 and a fix in 42.21 for an exploit that let players join without Steam authentication. In the in-game server browser, 42.21 also made the "Server Update" column show the last wipe, which is useful to know whether a server's world is fresh.
We did not find official instructions for hosting steps such as ports or SteamCMD in the Steam announcements, so check the official Project Zomboid wiki or your server provider's guide for those.
Mods and multiplayer
The Steam page lists Steam Workshop support, and mods are a big reason many groups pick a server. Three points from The Indie Stone's own posts:
- Only Lua-based modding is officially supported. Java mods, loaders and frameworks are not, and The Indie Stone warns they can break with any update.
- Java mods usually need manual installation. The Indie Stone's advice is to only install mods from sources you trust and to prefer open-source ones.
- Security changes can hit mods. 42.20.4 disabled the
loadstringandloadstreamLua methods, and 42.21 re-enabled them after further investigation.
So before a group night, agree on the mod list with the server admin and update everything at once. If a mod shows on the Workshop, that alone does not guarantee it works on the current build.
What to agree on before you start
- The build: Build 42 on stable, or
legacy41. Settle this first, before anyone downloads anything. - The server: which one, and whether it has a wipe schedule.
- The mod list: one list for everyone, same versions.
- PvP rules: is it a cooperative base, or can players raid each other?
- Roles: who farms, who handles power and water, who scouts and drives.
- Time zones: survival worlds move on while you sleep, so overlapping play hours help.
Finding a survival group
You have several real options, and they work better together.
Friends and Steam
The easiest group is one you already have. Pick the build and the server together, and keep one person responsible for the mod list.
Server communities
Public servers often have their own Discord with rules, wipe dates and regulars. Joining one is the quickest way to meet people who play at the hours you do.
Discord LFG servers
General LFG servers work for a one-evening team. Say your build, region, playstyle (cooperative or PvP) and time zone. Our list of the best LFG Discord servers in 2026 shows where to post.
GameVerse
GameVerse is a desktop app for Windows, macOS and Linux, with mobile coming soon. It shows players online now for the same game and region, chill or competitive, and lets you message them, with up to 8 players per search. It does not match on rank, role, schedule or game build, so use the built-in messaging to agree on Build 42 or legacy41 and the server before you join anyone. You can look at the Project Zomboid page or browse find players.
Common problems
- Can't join a friend's server: check you are on the same build. A Build 41 client and a Build 42 server do not mix.
- Mod errors after an update: wait for the mod author to update it, and have the admin and players update together.
FAQ
Does Project Zomboid have multiplayer in Build 42?
Yes. Multiplayer is part of Build 42 on the stable branch since 42.20 on July 29, 2026, and the Steam page lists online co-op, online PvP and split-screen co-op.
How many players can a Project Zomboid server hold?
The 42.20.3 hotfix added support for up to 254 players. The real limit depends on how the server is configured and the hardware behind it.
Can I play Build 41 and Build 42 together?
No. A server runs one build, and Build 41 saves do not carry over to Build 42. Players who want Build 41 opt in to the legacy41 beta branch in Steam.
How do I go back to Build 41?
In your Steam library, right-click Project Zomboid, open Properties, and under "Game Version & Betas" select legacy41.
Are mods safe in Project Zomboid multiplayer?
Only Lua mods are officially supported. The Indie Stone recommends installing mods only from sources you trust, and warns that Java mods are unsupported and can break with any update.
How do I find people to play Project Zomboid with?
Join a server community with its own Discord, ask in the official Discord or on r/projectzomboid, or look for players online now with a tool like GameVerse. Agree on the build, server and mod list in the first message.