Designed for the fourth and fifth-generation Apple TV models, the new tvOS 11.4 developer beta can be downloaded onto the Apple TV via a profile that's installed using Xcode.
It's not yet clear what new features the tvOS 11.4 update will bring, but it's likely to include bug fixes for issues that have been discovered since the release of tvOS 11.3.
Apple's tvOS updates have historically been minor in scale. tvOS 11.3, for example, introduced Match content support, automatic frame rate switching on the fourth-generation Apple TV, and automatic mode switching for AirPlay video sessions.
We'll update this post should any new features be found in the update.