SABRE PRO MQA: I2S vs USB

[Giovanni]

Hi Giovanni

IIS connection is not two-way communication ports, so front end device could not recognize DACs via IIS cable (HDMI cable)
MQA only could be handled through USB connection. 

which is better, it may related to your preferences. 

Thank You Cao . A last question about Sabre pro mqa DAC
I upgraded the firmware at 2.7 version
what about the 3.1 version? Is disappeared in the download section.
thanks again.Giovanni