S1 incompatibility issue with Play:3s and Connect:Amp

Incompatible in what way? What error are you receiving? Are all devices running S1? For instance, my PLAY:3s run S2, so would be incompatible with an S1 system, although I’m unsure how that would present itself as an error. Have you called Sonos Support to discuss it?

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Looking at your profile you own an Arc which isn’t S1 compatible. That said were all speaker working properly if you grouped them with the Arc? Otherwise you would have to run a S1 and S2 system and they cannot be combined.

So please explain why you downloaded the S1 app.

If you updated the Play3 and Connect Amp when you added the Arc, they are now controlled by the new app. Your Play1 can also be updated to the new app if you wanted to do that but your ZP is not compatible with the new app. 
 

Depending on how your system is configured, you can either downgrade the Play3 3 and Connect Amp back to the S1 app and only keep the Arc on the new app, or you can upgrade the Play1 as well to the new app and only keep the ZP on the S1 app

The zp might be eligible for a 30% trade-up discount on a new Sonos. You would get to keep the zp too.

A used S2 Connect might be an option, not an S1 version.