When Sonos announced forthcoming support for AirPlay 2 back in October, it was pretty vague about exactly what that would look like. Now, it's clarified matters, and while support is definitely on its way, there are a few caveats involved. In an announcement to MacObserver, the company says that AirPlay 2 will only be compatible with the Sonos One, Sonos Play:5 and Playbase. Older speakers won't have native support.
But here's the workaround. AirPlay 2 will work on older speakers if they're grouped with compatible models (that is, the ones listed above). So a set of Play:1s can utilize AirPlay 2 as long as they're grouped with a Sonos One, for example. Basically, if your speaker has touch controls, it'll support AirPlay 2. If it has buttons, it'll need to be part of a group to support it.
When support will actually arrive is another matter, and probably up to Apple, rather than Sonos. When Apple announced HomePod earlier this year, AirPlay 2-enabled features such as multi-room playback and stereo pairing were held back until "later this year" -- and that's the most optimistic timeframe we can expect for Sonos support, too.