Unfortunately you can’t. The Boost will either work on S2 or S1, but not both at the same time.

That’s disappointing but thanks for the speedy response.

it sucks that us early Sonos adopters have to deal with stuff like this.

IMO the original Sonos equipment should be able to work with the new Sonos 2 app !

Is there any way I can get my Play 5 gen 1 to connect to my Sonos 2 app?

No, that speaker is not compatible with the S2 app.

Thanks Mr. T again for the speedy reply. I appreciate it! :-)

The simple fact is there isn’t enough RAM on S1 devices in order for them to hold the S2 system, including the S2  speaker definitions.