Hi everyone,
I installed the latest version of Rasplex on my Rpi 2 and manage to select my hifiberry digi as default sound device output in rasplex preferences.
I do hear a sound when I am scrolling through my library, but then when I start a movie, nothing!
There is an issue with the hifi berry and the onboard Bluetooth of the Pi3 (they describe it over at HifiBerry https://www.hifiberry.com/2016/03/important-news-on-compatibility-with-the-raspberry-pi-3/ ). OpenElec have already updated their code to fix the incompatibility, so just need to do the same for RasPlex.
Once that is done my system will be perfect, Hi-Res music, HD audio and all my content in one easy to use place.
Can confirm that HiFiBerry is working fine in next release, no workarounds, only usual changes to config.txt on first flash of Rasplex to SD card. If you go the auto update route then nothing to do except remove any workarounds you’ve tried.