Allo Digione and Hardware Mixer?

I just purchased a new Allo Digione and installed the latest Volumio on my Raspberry Pi 4.

Under playback options I only can choose None or Software for volume control.

How do I get hardware volume control working? I use volume control in my system via Volumio and want the highest possible sound quality.

My previous XMOS XU208 USB to SPDIF converter worked fine with Volumio and hardware mixer.

OS info

Version of Volumio: 2.699
Hostname: volumio
Kernel: 4.19.86-v7l+
Governor: performance
Uptime: 0 days, 0 Hrs, 33 Minutes, 40 Seconds

Audio info

Hw audio configured: Allo DigiOne
Mixer type: Software
Number of channels:
Supported sample rate: 

Board info

Manufacturer: Raspberry Pi Foundation
Model: BCM2835 - Pi 4 Model B
Version: c03111 - Rev. 1.1
Firmware Version: Nov 29 2019 18:44:32 - aabb1fb5c19d80db268aeccd67b9f4e0f3d48a2a

CPU info

Brand: Processor rev 3 (v7l)
Speed: 1.50Mhz
Number of cores: 4
Physical cores: 4
Average load: 10%
Temperature: 52°C

Memory info

Memory: 4044924 Ko
Free: 3417028 Ko
Used: 627896 Ko

Storage info

INTERNAL storage - Size: 12627Mo Used: 253Mo Available: 11711Mo (93%)

screen shots of volumio config for digione

There is no hardware mixer in the Digione as far as I know (pretty sure but I only got mine for 2 days now).

If you want the best audio quality, you should not enable any volume control in volumio with the Digione.

Yes, no hardware volume for SPDIF is possible. Set Volume to none for best audio quality

confirmed, that is what allo has told me, no hardware mixer on the digione.