Project Zomboid Build 41 or Build 42 for your server?
Updated 24 October 2026 · 3 minute read · Project Zomboid · By Exclsv Support
Build 42 is Steam’s public branch; Build 41 is the legacy41 branch. Players need the same build as the server, and many Workshop mods support only one of them.
Which to choose
- Build 42 if your group plays the current game and your mods support it.
- Build 41 if your group has stayed on legacy41, or you rely on mods that only support Build 41.
- Everyone joining needs the same build as the server.
Switching build
Choose the branch in HQ, under Settings, Updates. Switching reinstalls the server, with a backup first, so you can go back.
Mods
Build 42 mods use a different format from Build 41. When you paste a Workshop collection, HQ writes the mod lines in the format for your build and flags mods that only support Build 41.
Keep both
A saved setup is a complete copy of your server: game, version, mods, settings and world. Keep a Build 41 world and a Build 42 world as two saved setups, and switch between them in seconds.
If it doesn’t work
Players can’t join after a switch
They need the same build as the server. In Steam, they choose the matching branch for Project Zomboid under Properties, Betas.
Some mods stopped working
Those mods probably support only one build. Remove them, or switch back with the backup HQ took first.
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