So, what is UI Compatibility Mode? It’s Apple’s way of ensuring that your app’s UI appears in macOS 26 and iOS 26 just as it did on previous OS versions. No Liquid Glass effects, no unexpected changes in control sizes or behavior, everything stays as you designed it. This means your pixel-perfect layouts from older OS versions, like Sequoia or iOS 18, will continue to look exactly as intended.

More technically, when UI Compatibility Mode is enabled, your app behaves as if it were compiled with an earlier SDK.

The caveat: Apple only guarantees this behavior while macOS 26 and iOS 26 are current. With the next major OS releases, this mode may no longer be available, so it’s a temporary solution.

The upside: At the time of writing, Apple is still refining these OS versions with point releases. If you need your app to run on macOS 26 or iOS 26 with full compatibility, you can enable UI Compatibility Mode in the Inspector Panel under Build Settings > macOS and Build Settings > iOS.

When enabled, both your debugged apps and the built versions (including those submitted to Apple via Publish) will look and behave on macOS 26 and iOS 26 as if they were compiled with the previous SDK. In fact, the behavior is even more consistent than if they had been compiled using the prior Xojo release.

Below, you can see how the same app appears when running on macOS 26 and iOS 26 with UI Compatibility Mode turned off (showing Liquid Glass and all the new UI effects), compared to how it looks when the switch is turned on:

The Last Word

All in all, macOS 26 and iOS 26 introduce a major UI overhaul, which can change the appearance of existing layouts. To help developers, Apple has added UI Compatibility Mode, which lets your apps appear on these new OS versions just as they did on previous releases—no Liquid Glass effects or layout changes. Technically, enabling this mode makes your app behave as if it were compiled with an earlier SDK. While Apple only guarantees this behavior for macOS 26 and iOS 26, it ensures consistency for both debugged and built apps, including those submitted via Publish.

UI Compatibility Mode gives you a choice: enable it to preserve your exact layouts across all OS versions, or leave it off to adopt the new macOS 26 and iOS 26 look and feel, which may require adjusting your UI for some quirks.

Javier Menendez is an engineer at Xojo and has been using Xojo since 1998. He lives in Castellón, Spain and hosts regular Xojo hangouts en español. Ask Javier questions on Twitter at @XojoES or on the Xojo Forum.

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Apple released macOS 26 and iOS 26 today, the first versions to ship with Apple’s new Liquid Glass look and feel.

The current release of Xojo (2025r2.1) runs smoothly on macOS 26 and can build apps that run on both macOS 26 and iOS 26. However, because 2025r2.1 uses an older version of Apple’s SDKs, many controls in both the IDE and the apps you build will still use the previous look and feel when running on these new macOS and iOS versions.

We’ve been working throughout Apple’s beta cycle to bring full support for Liquid Glass to Xojo. As you might imagine, Apple made a lot of changes to the OSs along the way — changes that affected things like our layout editor, control sizing, and behavior. Some of these changes were still happening very late in the process. Now that macOS 26 and iOS 26 are officially shipping, we finally know what the end result looks like and how it behaves.

Supporting Liquid Glass and the underlying system changes is a big undertaking and we still have more work to do. Since we build Xojo with Xojo, this means updating not only the Xojo framework but also parts of the IDE itself so it looks and behaves correctly on macOS 26 with Liquid Glass. Our goal is to let you use Liquid Glass in both built-in Xojo controls and third-party party plugins as soon as possible. That’s why the next release of Xojo, 2025r3, will be built for macOS 26 and iOS 26, giving your apps the latest look and feel while still allowing them to run on older versions of macOS and iOS. This includes projects still using API 1 windows and controls.

Because of the scope of these changes — along with other big, exciting features in the works — the testing cycle for 2025r3 will be longer than usual. As a result, 2025r3 will likely be our last major release of the year, followed by any needed point releases. The good news is that 2025r3 will pack in everything you’d normally see across two releases, plus more. It’s shaping up to be one of the biggest Xojo releases in recent years, with plenty beyond just Liquid Glass to look forward to. Additionally, the updates for 2025r3 aren’t limited to macOS or iOS — there are improvements and new features coming for all platforms, so every Xojo user benefits.

If you have a current license and would like to get early access, we’d love your help testing 2025r3. Just reach out and we’ll be happy to add you to the beta program. We can’t wait to hear your feedback once testing begins!

If you are a long time Xojo user, you know we have been through a lot of big changes like this. Sometimes we get it all done in a single release and sometimes it takes a few to get to 100%. Regardless, our goal is to make the transition for you a smooth one.

Geoff Perlman is the Founder and CEO of Xojo. When he’s not leading the Xojo team he can be found playing drums in Austin, Texas and spending time with his family.

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