3/2/22 update: App stopped working on my new Android 12 phone, I suspect a recent update. It can't find my system even though no settings have changed. My old 8.1 Android phone still works fine on all spkrs ## Great speakers but app leaves a lot to be desired. Confusing interface, limited functionality and it quickly runs out of 'slots' for playlists etc. ("Sorry you have no slots available to add this song to your Sonos playlist"). I've found it doesn't work well with Amazon music or Spotify.