Hifiberry Digi+Pro no volume control

Recently installed my Hifiberry Digi+Pro board in latest Volumio release 2.3… and works fine now. Bought the board a year ago to connect my I2S DAC to it, but the board was not supported by Volumio till recently. Now it works fine and great with Allo isolator in between.

However the volume control is not working anymore. Not in the Volumio webbage neither in Spotify (connect used). In the Volumio playback menu the hardware or software volume control can not be configured anymore.

My question is if it not possible because of the way the Digi+Pro works? Or just an omission in the Volumio release for this board and have to wait solution for this. For the Allo Digione the volume seems to work (also spdif output board as Digi+Pro but is missing I2S output).