Designed for the fourth and fifth-generation Apple TV models, the tvOS 11.2 developer beta can be downloaded onto the Apple TV via a profile that's installed using Xcode.
According to Apple's release notes, the tvOS 11.2 update enables a new AVDisplayManager feature for developers, designed to allow the device to automatically switch video display modes to match the native frame rate and dynamic range of video content.
The update includes support for switching the Apple TV 4K display output to SDR for apps that are GPU-bound when running in HDR and it re-introduces the Unwatched category in Home Sharing for Movies, TV Shows, and Home Videos.
Apple says tvOS 11.2 also adds new features, bug fixes, and security improvements to the tvOS operating system.
Update: Apple has also seeded a new version of tvOS 11.2 for public beta testers.