RimWorld 1.7 Waylith Engine: How to Try the Faster Beta

RimWorld just got a new engine, and somehow your colony of traumatized pawns will not even notice. Ludeon Studios announced Update 1.7 on October 12, 2026, moving the beloved colony sim off Unity and onto the studio's own in-house Waylith Engine. The pitch is simple: the game looks and plays exactly the same, and it runs a lot faster.

• What changed: RimWorld 1.7 runs on Ludeon's in-house Waylith Engine.
• Performance: 2 to 4 times better in Ludeon's tests.
• Saves: 1.6 saves load in 1.7, and 1.7 saves load back in 1.6.
• Availability: on the Steam unstable beta branch now.

How Much Faster Is RimWorld 1.7?

Ludeon says its tests showed a 2 to 4 times performance improvement. Two specific examples from the announcement tell the story better than any average:

• A late-game colony ran 2.2 times better than it did on 1.6.
• A modpack with 1,500 mods went from 14 minutes to 6 minutes to load.

If you have ever watched a late-game RimWorld colony slow to a slideshow while forty colonists, three hundred chickens and a mechanoid raid all path across the map at once, you know why this matters. The late game is where RimWorld's best stories happen, and it is also where the old engine struggled the most.

Ludeon notes that results will vary depending on your PC and your mods. These are the studio's own figures, so expect community benchmarks to fill in the picture over the coming days.

Will My Saves and Mods Still Work?

This is the part that made the community exhale.

According to Ludeon, 1.6 saves load on 1.7, and saves made on 1.7 still work if you go back to 1.6. That two-way compatibility makes the beta a low-risk experiment. Still, back up your favorite colony first. You know the one.

On mods, the studio says most work without changes. Some may show up flagged as potentially unsupported, and Ludeon explains that this is only because the version number changed. Mod authors are being asked to publish a 1.7-compatible version to clear the flag.

For modders, the engine brings real upgrades: access to the latest C# features, easier construction of complex mods without a large performance cost, and more accessible large visual changes and custom effects. Given that RimWorld's mod scene is basically a second game, that is a big deal.

One caveat from the announcement: PCs more than 10 years old may not be able to run 1.7.

How to Try the RimWorld 1.7 Beta

The update is opt-in for now. Here is the path Ludeon gives:

1. In Steam, right-click RimWorld and open Properties.
2. Go to the Betas tab.
3. Select the unstable branch.
4. If prompted at launch, choose Play 1.7 Unstable.

The main branch stays on 1.6 for now, and Ludeon has not given a date for the full release. It is called unstable for a reason, so treat it as a preview.

Why a 13-Year-Old Game Changing Engines Is a Big Deal

Swapping the engine under a live game with thousands of mods is the kind of project most studios would never attempt. Ludeon did it while keeping saves compatible in both directions. That is a serious technical flex, and a generous one, since it arrives as a free update.

There is also a tease. Ludeon says it is developing another game on Waylith, with no details yet beyond a cheerful note that it is working on something new. A studio that spent years simulating organ harvesting and tragic pet deaths now has its own tech and a second project. I am equal parts excited and afraid.

It caps a great stretch for long-running PC favorites, following Valheim 1.0 and its Deep North update and the Team Fortress 2 summer community update. More in our gaming coverage.

Sources: Ludeon Studios blog — October 12, 2026; RimWorld Steam news — October 12, 2026; PC Gamer — October 13, 2026.