Volumio iOS app and miniDSP SHD - master volume control

I have a miniDSP SHD and I’m frustrated that I can’t control the master volume over AirPlay in its Volumio software. Does the Volumio iOS app allow full volume control of the SHD?

Volumio Information

Volumio Version: current (updated yesterday)
Hardware: miniDSP Studio SHD (pre 2021)
DAC: irrelevant

Unfortunately this forum only deals with the standard, freely available Volumio Software.
For specific implementations, in this case miniDSP, it is best to open a ticket at their helpdesk.