Which binding in openHAB 3.2.0 can I use to connect to the Hornbach Smart Home Gateway WSR 1706 V 1.0

How can I connect my Hornbach Smart Home Gateway to openHAB 3.2.0?

The Hornbach gateway looks like a Vera Plus. There seems to be an OH MiOS Binding that might work with your Hornbach gateway - but IMHO the chances are vanishingly small.

An additional note:
MiOS used to expose its devices as UPnP devices, so the UpnpControl - Bindings | openHAB might be worth a try (but the Upnpcontrol Binding might be limited to AV devices).

Could you link to the OH3 version of this binding? (That isn’t for the Xiaomi Mi IO devices?)

MiOS isn’t related to Xiaomi in any way. MiOS was developed by Micasaverde and Micasaverde was bought by eZLO in 2018(?).

I couldn’t find an OH3 version of this binding, but maybe I didn’t look hard enough.

I’m aware of this, hence asking because you said

when I’m fairly certain one doesn’t exist for OH3.

@CHH if it really is a MiOS device you might have luck with some of the methods discussed in here:

I did use the http binding during my 2 to 3 migration but it was so strenuous on my vera edge, it kept freezing, being super slow and generally unreliable. In a fit of frustration I ripped off the bandaid and converted to native zwave support on an aeotec zstick gen5 I had. It’s better than the http method but the vera was a fantastic performer for zwave. I have had lots of additional zwave trouble on OH3.

I had to buy new thermostats and convert my zwave valve over to arduino mqtt cause they kept dropping off the network and Aeotec support was completely useless. They were fine on Vera but trash on Aeotec/OH FWIW.