I think it should be possible to get your your system onto the latest S1 firmware.  It is sometimes the case that a unit is too far out of date to update in the normal way.  But on past cases I have seen ut has been possible for Sonos Support to force an update.  I would go back and challenge them on this.  You may get a different answer from a different Support person.

What Sonos devices do you have?

Thanks for the quick response.  I’m a retired Systems Engineer and the response didn’t sit right with me but I didn’t feel like be confrontational.  New tech’s just don’t understand the concept of just ‘making it work’ regardless of what the ‘book’ says.  Maybe I’ll try to find the tech with white hair who talks to himself.

System is Connect / Connect:Amp / Play:5 / Play:3 

You presumably have a wired Sonos device?  If so is that a bridge or a Sonos speaker / player?

All players/streamers. No Bridges or extenders.

Wired (Cat 5) - 1 - Connect / 2 - Connect: Amp / 1- Play:5

Wireless (SONOSNet) 1- Play:5 / 2- Play:3

No Bridges or other Sonos equipment

If you have decided to update to latest S1 firmware I would power off everything except the wired P:5, and then “check for updates” in whatever app you are currently using (is that the S1 app or the app that waa in use before the S1/S2 split.

If the Play:5 updates OK, please post back for further guidance, If (more likely) the update fails, call Sonos support and insist that they force an install of the latest firmware   They can definitely do this.  If first line support says they can’t then ask to speak to second line.

I really believe that it is inconceivable that your speakers are no longer capable of running under current S1 firmware.