You may have been sold an item that had been in storage for a while but nobody then was aware of any difference or the possible consequences.

So I don't think you were ripped off.  On the label on the bottom, just before the serial number, is a four digit date code in the format YYMM. What do yours have?

Following up on my own question. The date code on one of the systems is 1705 and the other is 1706.

Everything I’ve been able to find says both of these should be S2 compatible so maybe the S1 App and the Sonos.com / System page are both just wrong?

The Sonos.com / System page clearly says Gen 2 on only one of the Connects...

They really should be S2. What are the implications for you? Do you want to update your whole system to S2?

I want to upgrade my whole system but the warning was scaring me off. If I do the upgrade is there any way to downgrade in the event the one device gets “stranded” on S1?
 

I run a fitness centre so we have Play 3 in the smaller rooms and Connect driving large speakers for the gyms. I really can’t have one of the devices missing.

This article sets out the position on downgrading.

https://support.sonos.com/s/article/4845?language=en_US

Are you doing this with a mobile app or the desktop app?

If you are using the desktop app then abandon it in favour of a mobile app. 

We use the mobile app. I will probably go ahead and try the update as long as there is a way to downgrade.

Thanks for the help!

It would be helpful if you were to post back with the outcome. I hope it works for you. 

I finally found some time to come in after hours and do the update of our system to S2.

All of our Connect and Play:3 successfully updated to S2 (including the Connect which the https://www.sonos.com/myaccount/system/households/devices/ page says is not Gen 2).

The only problem I encountered was that several of our older tablets can’t run the Sonos S2 app so they will have to be relegated to other purposes.