RimWorld Update 1.7: The Waylith Engine Arrives
RimWorld update 1.7 is the biggest technical change in the game’s history: Ludeon Studios announced on October 12, 2026 that the game is moving from Unity to the Waylith Engine — a custom in-house engine — with performance improvements of 2-4x in their tests. The main Steam branch stays on 1.6 for now; 1.7 is playable today on the unstable beta branch.
What Changes in 1.7
- Same game, faster engine. The game “looks and plays exactly the same,” but startup, load times with big mod lists, map generation, world generation and ticks-per-second all improve.
- Stress-test results. Ludeon saw a late-game colony run at 2.2x better performance than on 1.6, and a 1,500-mod pack load in 6 minutes instead of 14. Individual results vary by PC and mods.
- Save compatibility. Your 1.6 savegames load on 1.7, and 1.7 saves work if you switch back to 1.6. No action needed from players.
- Mod compatibility. The vast majority of mods work on 1.7 without author changes. Some show a yellow “potentially unsupported” warning only because the version number changed.
What This Means for Modders
- Most mods need no changes; Ludeon asks authors to publish a version marked 1.7-compatible so the yellow warning clears for players.
- Waylith gives modders more power: latest C# language features, easier high-performance complex mods, and more accessible big visual effects.
- Over two dozen modders helped test Waylith before launch.
How to Try Update 1.7
- Open Steam → right-click RimWorld → Properties.
- Select the Betas tab and choose branch “unstable”.
- Restart Steam if needed, then choose “Play 1.7 Unstable”.
Note: 10+ year-old PCs may not run 1.7 — report issues on the official RimWorld development Discord.
One More Thing
RimWorld isn’t the only game on Waylith — Ludeon is working on something new using the same engine. They also credit RocketWerkz’s Brutal framework for making Waylith possible.
RimWorld 1.7 FAQ
Will my mods break in 1.7?
Almost certainly not — the vast majority of mods run unchanged. A yellow warning just means the version number changed, not that the mod is broken.
Can I keep playing 1.6?
Yes. The main branch stays on 1.6 until 1.7 is fully released, and saves are compatible in both directions.
Source: Ludeon Studios — Announcing the Waylith Engine and Update 1.7 (official, Oct 12 2026). Information compiled per official statements; individual performance results may vary.