Can I connect my recently purchased secondhand sonos 5 gen 1 to my pair of play 1s that are running in the sonos app, of which I can't connect them to the sonos 1 app but will allow me to connect the sonos5, been at it ages, getting contradicting information saying I could downgrade my play 1s to the sonos 1 app,

But with no success. 

Could someone please help me before I go mad.

Regards Marko.0121