Sadly after all that, todays upgrade broke the I2S audio again. The card is detected by aplay -l and selected in kodi, but no sound.
Have you tried getting into contact with the Kodi developers?
No, because they'd probably ask me something technical about what/how Xbian works I wouldn't know the answer!
I run Kodi (15.2 Git:2015-12-04-858ee60) on RPi2. After latest upgrade http server is working again. No issues with RSS feed and I2S DAC.