I have 5 Sonos devices integrated into ST: Two Play:5’s as a paired L/R set with a Sonos base in our living room, one Play:1 in the bathroom and a Play:5 in the Kitchen. I most always have them grouped using the native Sonos APP with the Kitchen Sonos being the lead Sonos in the music selection and grouping.
I configured the ST Sonos Notify APP to play a canned ST message when our mailbox with a contact switch is opened “You’ve Got Mail”. The Sonos system never plays when you expect it or rarely at all. Sometimes the Sonos Notify APP pauses the Sonos group that is playing, and plays nothing. When I check why, the “You have Mail.mp3” is queued but not playing. I have to play the message and then manually restart the music. Needless to say, I have de-installed the ST Sonos Notify APP. I do not use ST APP to control my Sonos systems since the native Sonos APP does that so well.
Many ST community forum members have been very disappointed in ST and the weak Sonos integration when it comes to having Sonos either play music or suspend music currently playing and provide a custom message and return playing the song that was playing before the Sonos Notify.
The ST Sonos Notify App might work for some people who do not group their Sonos speakers or have them playing when an event fires, but that is not how we use our Sonos system. Why have Sonos and not group or have them play all the time?