Shelly Plus PM Mini

Where can I find or who knows what version of OH does support this new Shelly device?
My current OH 3.4.1 doesn’t support it. I get the message “IP address of the Shelly device is missing”

Go to the shelly binding documentation page: Shelly - Bindings | openHAB
You can switch between current version and archived version of the documentation and search for the different shelly products that are listed there.
As long as we can trust the documentation it looks like you need to be on 4.X version to get support for it.