I have just finished installing the Digi+ on a Rpi3. I am running Openelec (the version that comes with the Digi+ drivers) and have thoroughly followed the steps to enable DTS on your website, so everything is set exactly how it's supposed to.
Unfortunately I get no sound at all when playing a movie. In the GUI sound works fine, which implies that the physical cable connection is fine.
Can you please help? The Rpi3 is connected via toslink to my LG HTS that supports DTS and works flawlessly when plugged to my laptop via SPDIF.