In the latest beta versions of iOS and tvOS released earlier today, iOS 11.3 beta 3 and tvOS 11.3 beta 3, Apple has removed support for the AirPlay 2 protocol. That indicates strongly indicates the feature won’t ship when both software versions officially land to the public this spring.
AirPlay 2 allows multi-room audio and the ability to stream music to multiple sources simultaneously. The Apple TV also appeared in the Home app.
The protocol will also allow multiple HomePods to be paired in a stereo configuration and act as a multi-room audio source.
More than likely, AirPlay 2 will be re-introduced again with iOS 12 sometime later this year.