The AirPlay 2 update allows you to play multiple rooms between multiple Generation 2i speakers or systems and other AirPlay 2-enabled devices, including HomePod, Apple TV, selected speakers from Sonos, Libratone, and Bang & Olufsen. and select audio receivers from Denon and Marantz.
With AirPlay, users can easily stream audio from Apple devices to Generation 2i speakers, including music, movies, videos, news, podcasts, radio, audiobooks, and more from apps like iTunes, Netflix, and YouTube on a Mac or Mac iOS device.
AirPlay also allows Siri control of Apple Music playback or podcasts via iPhone, iPad, iPod touch, HomePod and Apple TV.
Generation 2i speakers and systems appear in most apps in the AirPlay Picker and on iOS 1
If you use the BluOS Controller app for iPhone or iPad, older bluesound speakers and systems can be grouped with a Generation 2i speaker or system so that the same AirPlay 2 content can be streamed throughout the house.
AirPlay 2 is Apple's latest wireless streaming protocol, released in May. Apple has a list of supported speakers on its website.