Apple releases watchOS 4.3.1, tvOS 11.4 with AirPlay 2
Apple has released tvOS 11.4 for Apple TV and watchOS 4.3.1 for Apple Watch users less than a week before WWDC where it is more than likely tvOS 12 and watchOS 5 will be announced.
tvOS 11.4
tvOS 11.4 can be downloaded over the air through the Settings app on the Apple TV by going to System --> Software Update. Apple TV owners who have automatic software updates turned on will be upgraded to tvOS 11.4 automatically.
The key feature, when paired with iOS 11.4, is AirPlay 2 functionality. AirPlay 2 is designed to bring multi-room audio to the Apple ecosystem, allowing the same music to be played on multiple devices throughout the home. tvOS 11.4 turns the Apple TV into an AirPlay 2-compatible device that's listed in the Home app for HomeKit devices. AirPlay 2 playback can be controlled through the Apple TV, through an iOS device, or using Apple's personal assistant, Siri, to play content using voice commands.
Apple has released a list of supported speakers their AirPlay page.
tvOS 11.4 also introduces performance improvements, security enhancements, and bug fixes for issues that have been discovered since the release of tvOS 11.3.
watchOS 4.3.1
The watchOS 4.3.1 release is a minor update that mainly includes bug fixes, security updates and performance improvements. It resolves an issue on startup where some watches would freeze on the Apple logo.