Hifiberry DAC + Hardware Vol Ctrl not working

Newest Volumio can’t control hardware volume for Hifiberry DAC +.

see this thread after-update-657-volume-control-t13107.html

My system has Rasberry Pi 4 B connected to Dynafrips Terminator DAC via USB. All works well and Volumio (ver. 2.699) detects a hardware volume. But on selecting this the volume does not change even though the display says that it should be. As I understand it since it was detected it should work. Any ideas. Thanks