A RimWorld Open World server needs players on RimWorld 1.4 with Open World mod version 1.3. The mod's Workshop page lists RimWorld 1.4 only, and Open World was last updated in July 2023, before RimWorld 1.5 and 1.6. On Steam, players switch to the version-1.4.3901 branch. On PlayNHost, the server's Player Version is already 1.3.
Why 1.4?
Open World is a community multiplayer mod by D12 and Primate Prime. Its Steam Workshop page is titled "[ABANDONDED] Open World", carries the tag 1.4, and was last updated on 23 July 2023 (the "1.3 patch"). Its authors wrote that they "decided to abandon and open source Open World" and that nobody plans to support it further.
RimWorld moved on since then: update 1.5 came out with Anomaly in April 2024 and 1.6 with Odyssey in July 2025. Open World was never updated for either. In October 2026 the main RimWorld branch is still 1.6, and Ludeon is testing update 1.7 on its unstable branch. When 1.5 came out, Ludeon wrote: "If you want to keep playing on version 1.4, use Steam beta branch "version-1.4.3901"".
Switch RimWorld to 1.4 on Steam
Ludeon's own steps for picking a branch:
- In your Steam library, right click RimWorld and click Properties.
- Open the Betas tab (Valve's current Steam client calls it Game Versions & Betas).
- Choose
version-1.4.3901. Steam downloads RimWorld 1.4.
Every player who joins your server does this. Switch back the same way to play the current RimWorld again.
Which Player Version does the server need?
1.3. Player Version is the Open World mod version the server lets in. The last mod version is 1.3, and the mod sends 1.3 when it connects. A new PlayNHost server is already set to 1.3, so there is nothing to change. If yours shows another value:
- Open your server in the panel and click the Settings tab.
- In Game Settings, set Player Version to
1.3and press Enter. - Click Restart now.
A player can check their mod version in RimWorld under Options, Mod settings, Open World, which shows Running version:. A mismatch gives the message "You have a different version of the mod from the server!": see RimWorld Open World server problems and fixes.
Which server version runs on PlayNHost?
PlayNHost installs Open World server v1.0.4, released on 5 May 2023 together with mod version 1.3. It is the last server release, so there is nothing newer to update to. The Open World Version setting is read only by the install, so changing it later does nothing to a running server. See RimWorld Open World server settings reference.
Questions people ask
Can I play Open World on RimWorld 1.5, 1.6 or 1.7? The mod was never released for them, so we cannot tell you it works there. Use 1.4.
Do the expansions work? Royalty, Ideology and Biotech existed in RimWorld 1.4. The world itself must be generated with them off: How to generate the world on your RimWorld Open World server. Anomaly and Odyssey came after 1.4, so they are not part of RimWorld 1.4.
Is RimWorld Together the same thing? No. RimWorld Together is a different multiplayer mod, and PlayNHost hosts it as its own server type. Open World players join an Open World server with the Open World mod; RimWorld Together players need that mod and a RimWorld Together server.
