Sounds like someone updated while you were gone on holiday. Those speakers will all still work with the S1 controller, you’ll just need to use the S2 controller temporarily to downgrade them back to S1.

Thx for prompt response. Stupid question (sorry!) - how do I downgrade them back to S1? Thx 

https://support.sonos.com/s/article/5097?language=en_US

Does anyone from Sonos read this?

I had the same issue. Either there's a bug or something Sonos are not telling us. How can my sonos play 1's update to S2 in their own.

I love the technology when it works but spent 4 hours of my life in this!

It seems to be the industry custom these days to make upgrades “easy” -- under the assumption that everyone would want to use the latest and greatest.

The transition from S1 to S2 is not automatic, but in my opinion it is a bit too easy. It is possible that a well meaning child or friend though that they were doing you a favor under the assumption that the old and clueless need all the help that they can get. In my orbit it’s the young ones who are clueless, but I don’t think that this is typical attitude.

If someone installs the S2 instead of the S1 controller on their phone/pad there will be a strong push to ‘upgrade’.

I think this problem would go away if the S1->S2 update process required the Sonos system password before proceeding (as S2->S2 updates do these days).