Airport Express already supported the original Airplay protocol. With Airplay 2, users can now connect it to legacy speakers and HiFi systems (via the audio output) to turn them into multi-room systems. From Apple TV, iPhone, iPad or Mac you can target multiple wireless Airplay 2 speakers for TV audio or music.
Airport Express now also appears in Apple’s ’Home’ app, allowing you to set room configuration and assign to it a name.
Airplay 2 is quickly emerging as a flexible multi-room protocols that allows users to mix and match speakers from various brands. Besides Apple TV and HomePod – and now Airport Express – Airplay 2 is supported on select products from Sonos, Marantz, Denon, and soon Bang & Olufsen and Libratone. Sonos was one of the pioneers in the area but it has chosen to partner with Apple. Google’s Chromecast protocol also supports multi-room features.
To update the firmware on your Airport Express you must use the Airport app on iOS and macOS. Only the 2nd generation Airport Express – that has been discontinued – supports Airplay 2.