The developer found in the first beta version of iOS 11.3 and tvOS 11.3 features that indicate the imminent emergence of technology AirPlay 2. In particular, it is about supporting multiroom on Apple TV when playing music from the iPhone.
If you install iOS 11.3 on your iPhone or iPad, and tvOS 11.3 on the fourth or fifth generation of Apple TV, you can use AirPlay 2 to play music on multiple devices at once.
For example, with two Apple TVs in different rooms of a house or apartment, it is possible to play the same song on both iPhone using the AirPlay 2 multi-room function.
After installing tvOS 11.3, the Home application prompts you to add Apple TV to HomeKit, and select a room for it. After that, Apple TV is displayed as an available device in the application.
AirPlay 2 technology was introduced as part of iOS 11 at WWDC in June this year. It includes functions such as audio playback in several rooms from iOS devices and improved buffering.
The functionality of AirPlay 2 is limited to devices that use the current beta versions of iOS 11.3 and tvOS 11.3. AirPlay 2 has not yet been officially released by Apple, but in the future, third-party speakers and HomePod will support this feature.