I’m assuming you mean Apple Music? The interface within the Sonos app did change recently; it now looks much more like the native Music app. I’m surprised that Sonos didn’t make a bigger deal of it actually; the limited options for Apple Music from within the Sonos app was my biggest complaint about the system and it’s a huge improvement.

The reason Sonos didn’t make a bigger deal about it is that Sonos had no real part in it. It was all done by Apple, using the API that has been provided to Apple from the beginning by the folks at Sonos, much as Sonos has given the exact same API to every music streaming company. Apple finally rolled out their new implementation of that API.