Sounds more likely like a local network issue, rather than a problem with the Sonos app. I’d certainly try a network refresh, by unplugging all your Sonos devices from power, then rebooting your router. Give the router a couple of minutes to come back up before plugging back in your Sonos. 

If this doesn’t resolve your issue (if it does, the problem is more likely with the router, not Sonos), then I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

If your music feed drops, that really has nothing to do with the new Sonos App. The App itself is merely a ‘remote’ and not a ‘player’ and once the music playback is started from the App on your Sonos products, it can be fully closed and the mobile device also powered off and the speakers will continue to play the audio ‘direct’ from the chosen source/service. If that ‘feed’ stops, then it’s unlikely anything to do with the new App - you need to perhaps look elsewhere to get to the root cause of your playback issue. So this reported issue would likely have taken place with the previous Sonos App aswell. My thoughts are to maybe start with reading the things mentioned in these two Sonos Support links below…

• https://support.sonos.com/en-us/article/music-service-audio-stops-or-skips
• https://support.sonos.com/en-us/article/reduce-wireless-interference

If the issues still persist after trying the things mentioned in those links, then it maybe best to reproduce the issue and immediately submit a Sonos system diagnostic report from within the Sonos App, note it’s reference and then contact/chat with Sonos Support Staff via this LINK and see what the Staff can perhaps suggest to help you to resolve the matter.