Could someone confirm that a working volume control is yet to be implemented in Volumio 2. Have run Volumio 1 with a USB Dac with fully working volume control. In current beta the volume control does not work, constant volume regardless of how you set the volume in the web UI.
Volumio 2 Beta 3, USB X-FI HD, Volume control does not work.
If you follow the development in this thread introducing-volumio-t3169.html
You can see when an update is released and what the changes are. Volume control is planned to be added in the next few weeks.