This is true for my Mytek Stereo192-DSD with the latest firmware, 1.7.6. I think in general, if your DAC/device driver needs the "2-wire", 4 channel, 176.4Khz DoP variant, there is not support currently. The latest firmware for the Mytek does do 2xDSD DoP over USB (2 channel @ 352.8 Khz).