How To Update Project Zomboid Server
To update your Project Zomboid server on Sparked Host, open the Startup tab in Apollo Panel, make sure Steam Auto Update is enabled and restart. The server downloads the latest version of its branch from Steam as it boots.
This is how to update Project Zomboid server installs without losing a world, including the branch change that catches most admins off guard since Build 42 went stable.
Take a backup before you restart. A Build 41 world won’t load on Build 42, and without a backup there’s no way back.
How Do Project Zomboid Server Updates Work?
Your Project Zomboid server runs a Steam branch, and every restart with auto-update on pulls the newest build of that branch. Players need the same game version on their client to connect, so everyone has to be on the same branch as the server.
Game updates and Workshop mods are managed separately. Updating the server does not automatically update Steam Workshop mods to a compatible version, which is why a server can be current and still crash on boot.
Most game server hosts include an automatic update feature in their control panel. In Apollo Panel, it’s a single setting, and the branch is another.
Back Up Your Server Files Before You Update
Back up your files before you update your Project Zomboid server, every time. Shut down the server first so the world isn’t saving while the backup runs.
In Apollo Panel, open the Backups tab and click Create Backup. For larger or modded servers, create regular backups too: a task in the Schedules tab can make one every night.
What to Include in the Backup
Backup copies should include server configurations and save folders. On Sparked, both live inside ServerFiles in the Files tab.
The world is in ServerFiles, inside a folder named after your server. Your game settings, including the .ini and sandbox settings files, are in ServerFiles/Server/.
If you want a copy of the host, download both folders from the Files tab or through SFTP.
How to Update Your Project Zomboid Server in Apollo Panel
The update runs during startup, so the whole process is one setting and a restart. Large patches simply take longer to download.
Enable Steam Auto Update in the Startup Tab
- Log in to Apollo Panel and select your server.
- Navigate to the Startup tab.
- Locate Steam Auto Update and make sure it’s enabled.
Startup tab in Apollo Panel showing the Steam Auto Update variable enabled
Restart the Server and Watch the Console
Important: restarting disconnects every player. Give them a warning in chat or update during a quiet hour.
- Open the Console tab.
- Click Restart.
- Wait while SteamCMD downloads the new version. The console log shows the progress before the game starts loading the world.
Console tab in Apollo Panel showing SteamCMD download progress during a restart
If nothing downloads, there was no update for your branch. That’s normal.
Confirm the Game Version
Launch your own Project Zomboid client and check the build number in the bottom-right corner of the main menu. If you can join, your client and the server are on the same version.
How to Switch Branches: Build 42, legacy41 and Beta Versions
Build 42 became the default stable branch with version 42.20 on July 29, 2026. Build 41 moved to the legacy41 beta branch, and The Indie Stone replaced the old unstable branch with a Pre-Release branch for testing upcoming updates.
Changing major game branches may require creating a new world. Build 41 saves don’t load on Build 42, so a server that jumps from one to the other starts a fresh map.
Which Branch Should You Use?
Steam Beta Branch value | Version | Use it when |
|---|---|---|
Empty (default) | Build 42 stable | Starting a new world or keeping a Build 42 world current |
legacy41 | Build 41.78 | Finishing an existing Build 41 world or keeping mods that only work on B41 |
42.19 | Build 42.19 | Finishing a world started on the 42.19 unstable branch |
Pre-Release | Upcoming Build 42 updates | Testing a beta version before it reaches stable |
Stay on the default branch unless you have an existing server with a world worth finishing. |
Change the Steam Beta Branch in the Startup Tab
Important: switching between Build 41 and Build 42 makes your current world unloadable on the new version. Create a backup before this step.
- Stop the server from the Console tab.
- On the Startup page, find Steam Beta Branch.
- Type or paste the target branch (for example, legacy41), or clear the field to go back to the default branch.
- Keep Steam Auto Update enabled so the server can install the new version.
- Start the server. Variables only apply after a restart.
Steam Beta Branch variable on the Startup page set to legacy41
Match the Branch on Every Player’s Steam Client
Each player who joins your Project Zomboid server has to select the same branch in Steam, or they’ll get a version mismatch error.
- Right-click Project Zomboid in the Steam library and choose Properties.
- Open Game Versions & Betas.
- Select the same branch as the server, or None for the default.
Post the exact branch name in your Discord or server description so nobody joins on the wrong build.
Do Workshop Mods Update With the Server?
No. Updating a Project Zomboid server changes the game files, not the mods, and an outdated mod stays outdated after the update. Players also need the same mod versions as the server.
After a major update like Build 42, many older mods stop working. Remove them from the Mods= and WorkshopItems= lines in your game settings, start clean, then add them back a few at a time and test each one.
Updating a Self-Hosted Server With SteamCMD
If you manage your own Project Zomboid dedicated server, SteamCMD is the recommended tool for updates. The Project Zomboid Dedicated Server App ID is 380870, and SteamCMD allows login anonymous for it, so you don’t need a Steam account that owns the game.
Stop the server, then run this update command, replacing C:\PZServer with your installation directory:
bat
steamcmd +force_install_dir C:\PZServer +login anonymous +app_update 380870 validate +quitvalidate checks the integrity of the server files. To stay on Build 41, add the branch flag: +app_update 380870 -beta legacy41 validate. If you type commands one by one inside SteamCMD instead, enter quit to close SteamCMD once the download completes.
On Windows, a self-hosted dedicated server keeps its data in the Zomboid folder: multiplayer saves in C:\Users\YourUsername\Zomboid\Saves\Multiplayer\ and configuration files in C:\Users\YourUsername\Zomboid\Server\. Back up both before each update.
Frequently Asked Questions
How do you update your server?
Enable Steam Auto Update in Apollo Panel and restart. The server downloads the newest build of its branch as it boots. On a self-hosted server, stop it and run app_update 380870 in SteamCMD.
How do I configure a Zomboid server?
Most game settings live in the server .ini file and the sandbox settings file in ServerFiles/Server/. Edit them in the Files tab, save, and restart so the new settings apply. For example, PVP, MaxPlayers and Password are all in the same file.
How do I keep my Project Zomboid server up after updates?
Back up before every update and keep Steam Auto Update on, so the server matches what players automatically get from Steam. A scheduled restart in the Schedules tab lets updates apply at a quiet hour instead of mid-session.
How do I fix “Getting server info” in Project Zomboid?
A player stuck on “Getting server info” usually can’t complete the connection because their branch doesn’t match the server, or the server is still downloading mods or loading the world. Check the console, confirm both sides use the same branch, and have the player verify the game files in Steam.
If Something Goes Wrong
Players get a version mismatch error
The client and the server are on different builds. Have players select the server’s branch in Game Versions & Betas, or restart the server so it pulls the same version they have.
The server won’t start after the update
An outdated mod is the usual cause, followed by a full disk. Read the last lines of the console log, remove the mod named in the error and restart.
Your world reset after updating to Build 42
The server moved to Build 42 and couldn’t load a Build 41 save. Set Steam Beta Branch to legacy41, restart, and restore your backup from the Backups tab if the world doesn’t load.
The update didn’t apply
Either Steam Auto Update is off or the server wasn’t restarted after a variable changed. Check both and restart. If it’s still on the old version, contact Sparked Host support with your server ID from Settings.
Updated on: 04/11/2026
Thank you!