I updated my Roon core and IOS devices to support 1.8 today. I also have a Raspberry Pi 3B+ with a Justboom Digi Hat running Roonbridge. The Rasperry Pi shows up as an ALSA audio device under Setup, but I can’t select it as the audio device.
I’ll try to update the OS and Roonbridge version to the latest versions soon and update this post. Hoping this will fix it.