Factorio: "Version mismatch" when joining your server

Factorio multiplayer requires every player and the server to run exactly the same game version and the same mods. That is a Factorio rule, not something we control, so no server setting can let an out-of-date player in.

A running server keeps the version it started with. On patch day Steam updates players right away while your server waits for a restart, so updated players get the mismatch until then.

1. Open My Servers and find your Factorio server's card.

2. Press and hold the yellow Restart button until the ring completes.

3. Wait for the status to show Online, then have everyone join again.

During startup the server picks up the newest stable Factorio build on its own. No reinstall, no file work, and your world is saved and backed up before the restart as always. A server that was powered off or sleeping does the same thing on its next start.

Two things to know:

• There is no update triangle for Factorio. Some games show an orange "update available" warning on the card; Factorio servers do not. The sign of a pending update is simply that freshly updated players cannot join.

• Restarting in the first minutes after a release can still bring the old build back. New stable releases take an hour or two to reach us after Factorio publishes them, so wait a bit and restart once more.

• They are on the experimental branch. Factorio's experimental releases run ahead of stable, and your server runs stable. In Steam, right-click Factorio, open Properties, then Betas, and set the dropdown to None. Steam downloads the stable version and they can join. Standalone players from factorio.com should install the stable build. We do not offer an experimental server channel, so there is no server-side setting for this.

• Their game has not updated yet. Quit and reopen Steam to force the download, then launch Factorio again.

• Nintendo Switch players need the matching Factorio update installed on the Switch, and can only join servers with no mods installed.

Factorio usually fixes mod mismatches for you: joining a modded server brings up the game's offer to sync mods with the server, which downloads the exact versions your server runs. That download needs a free factorio.com login inside the game.

After a big Factorio update, some mods take a few days to catch up. If a mod is stopping your server from starting, turn its Enabled switch off in the Mods card until the author updates it: see Mod load order and toggles.

If the error mentions Space Age, quality, or elevated rails, your server has Space Age DLC ticked in the Details tab of its Overview card, and every player needs to own the DLC to join.

Auto Restart, in your server's expanded Overview settings under Basic, doubles as set-and-forget updating. New servers come set to Every 48 hours; switch it to Every 24 hours (daily) and a server that goes quiet each day picks up new releases on its own. Scheduled restarts wait until the world has been empty for 15 straight minutes, and a player joining cancels them until the next quiet moment, so nobody gets pulled out of the factory. Details in Automatic server restarts.

There is no way to pick an older Factorio version, pin one, or run the experimental branch. Backups cover your save, not the game build, so restoring a backup does not put the server back on an older patch either.

Reach us on Discord or at support@haptic.gg. Include your server name and a screenshot of the version error the affected player sees.