I think you’re misunderstanding the world of Sonos, and how generations apply to the ecosystem. 
 

For instance, you say you have a PLAY:5. There are two generations of the PLAY:5, and a third one now called the Five, since the previous generations are no longer in production. The first gen of this speaker works only with the S1 software, while the second gen can run with either S1 or S2, but not both at the same time. The Five can only be driven by S2.

But your PLAYBAR and PLAY:1s will run under both S1 or S2, just like the PLAY:5 gen 2.

The CONNECT:AMP is a bit odd, it turned out there were two generations of it, but Sonos didn’t call it out at the time it received an upgrade. So it’s possible that it is either S1 only, or capable odd running S1 or S2. Your best bet is to log in here to check the status of your devices. If there is an ‘upgrade available’ flag next to it, then it’s first gen, and will only run S1. If there is no flag, then it will run either S1 or S2. 

Where to upgrade first would depend on where you spend more time, listening to the PLAYBAR, or the PLAY:5. If all your devices are S2 compatible, and you use the PLAYBAR more than the PLAY:5, I would consider an Arc to upgrade from the PLAYBAR.

However, again, if all devices are S2 compatible, and you listen to the PLAY:5 more often, I’d consider upgrading that as a priority with a Five, or even perhaps a pair of Sonos Ones.

Again, though, I’d want to update any components that are not S2 capable first. 

Thanks for the info.

I use the Playbar, Play1’s and Sub most often as the are the soud system for myTV.

However to get all devices using the S2 app, upgrading the Play5 first would do that.

Yes?

Dave

What feature(s) of S2 make you want to upgrade from S1 at this time?

The Play:5 gen 2 is no longer on sale (except used, of course).

As I said in my original question, I asked about upgrading my system, not specifically the app. although it's a consideration but not primary.

You can't upgrade one and not the other. The S2 system is controlled by the S2 app. The app is just a remote control.

I ask again - why do you want to upgrade at this time? What benefit do you imagine it will give you? If you stay on S1 you don't need to replace any of your equipment. Or you can buy a Play:5 gen 2 if you really want one and add it to your S1 system.