No, it is not true.  Some models can’t go back to S1 after being upgraded to S2, but from S1 to S2 is fine. 

Thank you.  Any thoughts on downgrading - should I do it ?  

I don’t see that many issues with the new Sonos App, personally speaking, but I guess it depends how you like to use the App and what features you’re looking for. The new Sonos App does a majority of the things I need with my multi-room Home Sonos system. 

If you're having problems with the current app and, more importantly, if your devices can ALL run it, I'd do it for sure.  From memory I have a feeling you need a device already on S1 to do it though but there are plenty here who could answer that categorically.

When S2 launched it promised so much that couldn't be done in S1.  The reality is it does very little different/in addition and looks remarkably similar still.

The new App supposedly promises lots too and I really look forward to that if/when it arrives - but for me, there's still quite a way to go to get there or even reach parity with its predecessor - and, as I don't have a device that necessitates the new App (Ace and possibly Arc Ultra?), I don't feel I'm missing anything at all and can do more than I could should I update.

I'd certainly not use the term downgrade either….

Thank you SJW and Ken for your replies.  I’m going to make sure I’m on the latest software version - right now I’ve lost volume control feature.  If I still have problems I’ll go back to S1.

If the setup is not using SonosNet and operating on your WiFi signal and you’re speaker(s) are having volume control issues, then I’d perhaps check the network connection SNR levels. See this link:

https://support.sonos.com/en-us/article/understanding-the-network-details-section-in-the-sonos-app

If the device supports a 5Ghz WiFi connection with an SNR level of 45dB, or higher, then I’d aim for that, as it ‘might’ help resolve the issue seen with volume control.

I don’t know what features you have or need from the new crappy app, but I have deleted it totally. I like many others are using the SonoPhone app. Works perfectly. Has all my music from my music sources exactly as the Sonos app had. It doesn’t have a timer nor can you adjust the treble and bass but that’s something that I did in the beginning and it’s remained the same. No speakers or rooms missing..and combine any rooms if you want.