if you look in the settings, under the RuneOS kernel settings, you'll see these instructions for I2S kernel modules:
Enable I²S output by selecting one of the available sets of modules (in this version you have to edit /boot/config.txt), specific for each hardware. Once set, the output interface will appear in the MPD configuration select menu, and modules will also auto-load from the next reboot.
so log onto your pi via SSH, and edit the /boot/config.txt file.
You'll see something that looks like this:
# Uncomment one of these lines to enable an audio interface
#device_tree_overlay=hifiberry-dac
#device_tree_overlay=hifiberry-dacplus
#device_tree_overlay=hifiberry-digi
#device_tree_overlay=hifiberry-amp
#device_tree_overlay=iqaudio-dac
#device_tree_overlay=iqaudio-dacplus
just uncomment the iqaudio-dacplus line (by deleting the #), save the file, reboot, and you should see then see it in the dropdown menu as an option in the MPD settings.
