However, RPI overlays are listed here....
https://www.raspberrypi.org/documentatio...ce-tree.md
For your requested Hifiberry DAC+
add a new line to /boot/config.txt (copy and paste below)
dtoverlay=hifiberry-dacplus
save ('ctrl+o' to writeout the changes. 'Enter' to accept the change, and 'ctrl+x' to close the terminal) then reboot and it should work.