Factorio only lets a player join when their game is exactly the same version as the server. The server’s version is on the World page. Either the player installs that version, or you change the server’s version to match them.
Find the server’s version
Open the World page. In the Game version card, Installed (1) is the version the server runs now. Next start runs (2) is the version it will use after its next start.
On 13 November 2026, factorio.com listed 2.1.24 as both the stable and the experimental server version.
- Installed
- Next start runs
- Update at every start
Option 1: the player matches the server
Ask the player to install the version shown under Installed. Their game must be exactly that version, for example 2.1.24.
Option 2: change the server
In the Game version card, pick a Version:
- Stable follows the newest stable release.
- Experimental follows the newest experimental release.
- One version keeps one number. Then pick the number in Which version, for example
2.1.24.
Choose Save. The server changes version at its next start. Restart it with Restart at the top of the server page. A restart drops everyone who is on, so warn them first with Message everyone on the Players page. Players need the same version to join.
Update at every start (3) decides if the newest version of that kind is installed before each start. With it off, the server stays on the version it has until you change it. With One version, the number never changes by itself.
Before you go to an older version
If it does not work
- The server starts on the wrong version. The change waits for the next start. Use Restart at the top of the server page.
- Save refuses the number. The panel says “factorio.com publishes no headless server (version)”. Use a number that exists, or choose Stable.
- Players are on the right version but still cannot join. Their mods differ. See mods mismatch on join.
- Crashes says “The world is newer than the game”. Pick that newer version, or Stable, on the World page.
More about the game: Factorio servers.
Sources: wiki.factorio.com: Multiplayer, factorio.com: Latest releases