Apple really wants you to use their …

Apple really wants you to use their music app and not to bal to “airplay 2” other sources on the Sonos it seems. If you’ve used volume up or down in your pocket this matters.

“Following Sonos version 9.0, if you have an AirPlay capable device in your household with AirPlay enabled, it will no longer be possible to control your Sonos system from the lock screen of your iPhone or iPad when using the Sonos App to initiate playback. This includes use of the hard volume buttons from the lock screen. It is still possible to use the hard volume buttons to adjust Sonos volume from within the Sonos app."

“If you aren’t using AirPlay, you have the option to disable third-party AirPlay endpoints and continue using lock screen control on Sonos. We recognize this isn’t an ideal solution for those who use AirPlay regularly at home, but if you prefer to continue using lock screen controls, refer to the device manufacturer’s instructions for disabling AirPlay.“