Ludeon Studios is moving RimWorld from Unity to Waylith, an engine it built itself, in update 1.7, the studio said in a Steam announcement on 12 October 2026. The change comes eight years after the colony simulator’s 1.0 release. Ludeon says the game should look and play the same, and that its internal tests show performance improving by two to four times.
Ludeon’s performance figures
The announcement lists faster start-up, faster loading with large mod lists, quicker map and world generation, and more ticks per second, the measure of how fast RimWorld’s simulation advances. Ludeon gives two examples:
- a stress-tested late-game colony ran 2.2 times faster on 1.7 than on 1.6;
- a pack of 1,500 mods loaded in about six minutes instead of about fourteen.
These are the developer’s own figures, and Ludeon says results will vary by PC and mod list. No independent benchmarks were available when this article was written.
Saves, mods and older PCs
Ludeon says players need to do nothing to switch. Saves from 1.6 load in 1.7, and 1.7 saves load back in 1.6. Most mods should work without changes, though some may show a yellow “potentially unsupported” warning only because the version number changed; modders are asked to publish a 1.7-compatible version to clear it. More than two dozen modders helped test the build, and for modders the studio highlights support for the latest C# features and easier access to larger visual changes and custom effects, as GamingOnLinux also reports.
The caveat is hardware. Ludeon warns that PCs more than about ten years old may not run 1.7, and asks affected players to report problems on its official Discord.
How to try the 1.7 beta
Update 1.7 is a public test for now. On Steam, players can open RimWorld’s Properties, go to the Betas tab and select the “unstable” branch. The main branch stays on 1.6, and Ludeon has not given a date for moving 1.7 to it. The announcement covers the Steam PC build only and does not mention the separate console edition. GameTales has not tested the beta.
A new Ludeon game on the same engine
Waylith is not a one-game project: Ludeon says it will power a new, unnamed game from the studio, with details to come later. The announcement does not say how long Waylith has been in development or why Ludeon chose to leave Unity.