Updating your Valheim server to 1.0

The order to update a Valheim dedicated server in, what the new chunked save format does to your world files and your backup scripts, and how to get back if it goes wrong.

The short version

Back up, strip your mods, update the server before you let anyone in, and expect a slow first boot while the world converts to the new chunked save format. A server left on the old build refuses every updated client with a version mismatch.

Steam updates clients the moment 1.0 goes live. Your server does not update itself unless something tells it to, and a server on the old build refuses every one of those clients with a version mismatch. That is patch day for most groups, and it is over in one restart.

The part that catches people out arrives afterwards, in the file system.

#Back up first, and look at it

Take a manual backup from the dashboard before you touch anything, then open the list and confirm it is there. A backup nobody has looked at is a guess.

This matters more than usual on this patch, because the update rewrites how worlds are stored on disk and there is no clean way back once that has happened.

#The save format changes underneath you

Iron Gate put a new save system on the public test branch on 6 May and have not shipped it to live. 1.0 is where it goes.

Today a world is two files sitting side by side, YourWorld.db and YourWorld.fwl, in worlds_local under your save directory. After the update each world is a folder, the database is split into chunk files inside it, and backups get folders of their own. Each save writes only the chunks that changed and the game verifies the write afterwards, which is the point: Valheim has lost worlds to corrupt saves for years and this is the fix.

Character saves are not affected.

One knock-on Iron Gate flagged themselves: some platforms cap how many files can go into cloud storage, and this turns a couple of files into a great many. That one lands on clients, not servers, and it is the kind of thing that surfaces a week later on somebody's Steam Deck.

#The conversion, and why first boot drags

Load a world that is not already chunked and the game converts it, taking a backup before it begins so nothing is lost if the conversion hits a bug. An established world with hundreds of build pieces has more to chew through than a fresh one.

Give the first boot a few minutes before deciding something is wrong. Watch the console rather than the clock.

#What this breaks in your tooling

Anything that expects two files with the same base name. In practice:

SFTP downloads that grab *.db.
Cron jobs or rsync scripts pulling the world to another machine.
Third-party backup tools written against the old layout.
Your own habit of copying the .db before a risky session.

All of it needs pointing at the world folder. Check it before the update, not after somebody needs the file.

#The update itself

On Hostd the Valheim image runs a Steam update on every boot, so 1.0 arrives with a restart from the dashboard. Nothing to install and no commands to run.

Anywhere else it is SteamCMD:

steamcmd +force_install_dir /path/to/valheim +login anonymous +app_update 896660 validate +quit

Order matters on patch day. Update the server, confirm it boots and reports the new version, then let people back in. Doing it the other way round produces a stream of version mismatch reports from players who cannot tell the difference between a broken server and one that is thirty seconds behind.

#Take the mods off first

Every plugin is compiled against the old build and none of them have been rebuilt yet, because there was no public test branch to rebuild against. Update to vanilla, confirm the server is healthy and people can join, then start putting mods back as authors publish. Iron Gate also note that the new save system has not been tested with mods at all, which is a good reason not to have any loaded the first time a world converts.

The sequence is in Valheim mods after 1.0.

#Getting back

Iron Gate's own advice is not to move save files between game branches by hand. If you need the old build, restore the backup you took beforehand onto it. A converted world does not drag backwards.

Steam's Betas tab can put a client on an older version. A world that has already converted is not going back on its own, which is the whole reason the backup step comes first.

#Next steps

#Frequently asked questions

Why do players get a version mismatch after the Valheim update?

Steam updated their clients and the server is still on the old build. Valheim will not let a client and server on different versions talk to each other. Update the server, then have people reconnect.

Where did my world.db file go after updating Valheim?

The new save system stores each world as a folder with the database split into chunk files, and backups in their own folders alongside. Nothing is lost, the layout changed. Any script matching *.db needs pointing at the folder instead.

Why is the first boot after the Valheim update so slow?

The game converts a world that is not already chunked, and takes a backup before it starts. An established world with a lot built on it has more to convert. It is a one-time cost on that first load.

Written and maintained by the Hostd engineering team. Last updated 2026-09-04. Notice a mistake? Tell us.