Same issue here.

Oddly enough I was playing from my Subsonic server this morning.  I hit the play button when I got home and it’s playing fine - just can’t do anything with it in the new app.

Same issue, just went back to version 16.1 (Android)

This was a deal breaker for me, I had to roll back to the previous android app.

Also no more now playing home screen widget was an issue. Sounds like from reading there's lots of other issues. 

Does anyone know of an alternative to the Sonos app on ios? 
I need to access my library locally, (SMB or Subsonic equivalent)
I'm really disappointed with Sonos, how can they release such a disastrous app, they should have left the old version alongside the new one.

Not an ios user but can you not just roll it back? 

Same issue here, this is a deal breaker. Sonos is a home system, it should connect to home servers

Support told me: 

“Subsonic doesn't show on the services on Sonos. I believe we never supported Subsonic since they do not work the way a normal music service would.”

Which clearly isn’t true. 

Personn

I personally use bonob, an intermediate plugin that connects a subsonic or navidrome instance.

Me too. I misremembered how it was added. Either way it no longer shows up as a service to add or play from.  

Clearly Sonos doesn't understand their customers. This is a terrible upgrade 

Can someone advise if there is a work around to roll back to the previous version of the app on ios? 

Unfortunately, there is no solution, you can’t downgrade an app on iOS.

Same issue here. Subsonic works on the new app for desktop windows pc but will not show on iOS or android. This is the only why I’ve been using Sonos speakers and now with the mobile app breaking this functionality my music library is now useless on this app. Please fix. 

Come on Sonos...You broke something that worked really well. Roll back the App untill you have it ironed out and tested properly

 I am unable to reach anyone via the Chatbot or telephone (wait > 70 minutes).

The newest iOS update broke the connection to Subsonic.  There is a HUGE community of us who use Subsonic, both in the US and abroad.  The newest desktop updated version still works, which is interesting.

Can you PLEASE have this repaired ASAP?  I invested a ton of time and effort into this Sonos system less than 1 year ago.  My family uses Subsonic for all of our music and playlists, and this really sucks.  Things are nonfunctional unless we walk into the basement and change the song on my office computer every time.

Sonos has become over the years more and more strange. From being a innovative company (I was one of the first customers in my country with a Sonos ZP80) to a tec company that is far away from customers and even does not listen to customers anymore. Their own agenda seems more important than customer needs.

The new upgrade of the system simply ignored my configuration and deleted the subsonic access to my music library….no cost-free or easy to install alternative is available anymore.

I still have one system with a S1 App which I will continue to use. My second system that migrated to the new Sonos has no worth for me anymore and will need to be put in trash! 1000 eur lost….thank you Sonos!!!!!

Same issue here: new Sonos update broke the connection to my home music server. Its also buggy as all hell connecting to the different devices, saying it cannot connect, but then does without warning. Thanks for the update Sonos! I worked around this by downloading SonoPhone. Back in business! Please please please fix this app or just give users an option to roll it back to the perfectly fine S2 controller.

Sonos has made my system totally unusable, best thing it can do now is play a radio station, I’ve lost access to over 10,000 CDs I’ve personally ripped stored on a nas and accesibile via Subsonic, I can’t even seem to find a way of adding the nas to Sonos.

Thanks for making my system totally redundant Sonos, good job.

As a suggestion, you could try Plex for your local music while they fix the app and possibly correct this. 

I’d need plex+, I love the flexabilty I have with subsonic, start playing at home via Sonos, add to a playlist using the web, then pick up where you left when out and about using iSub, at worst you have to listen to the same song twice, I already run jellyfin and subsonic, not sure the computer would thank me for running another media server on it, desktop app seems to fill the void while Sonos sort their proverbials out. 

I confirmed that both the Windows and Mac desktop apps still have access to Subsonic. 

Sonos, please add support back to the mobile apps!

Can confirm that this still works with the Windows desktop app. The new app is absolute garbage, I  can’t access Subsonic (Airsonic-Advanced in my case), and it crashes after 20 seconds on the loading screen 80% of the time.

This is really incredible. Now after some months of downgraded to 16.1 this app says that the app has to be actualized and it does not work anymore with the existing system. So it seems the option of downgrading is now also gone. I assume this has to do with a firmware upgrade on the speakers or not? Does anyone know? If yes, can I downgrade the speakers as well? On the subsonic forum I read this: 

http://forum.subsonic.org/forum/viewtopic.php?f=4&t=19008&p=79354&hilit=sonos#p79354

Does anyone know how and with which version of Sonos? Because with the android version I tested, subsonic is still not there as a service.

Fyi, there is an issue at GitHub for bonob, which gives hope that it can be made to work again with the new app - it apparently needs adjustments on the part of bonob.

So I'll try to be patient and wait until I buy the new sonos speakers I was planning to get until it works again.