Rune and Pi3/Digi+ not audio out option for optical

[davepitt]

Set up Rune 0.3 on Pi3. Have a Digi + to send via optical to external DAC. The only Audio Output Interface options are HMDI and Analog out. I cannot get Rune to give me optical out option. What am I missing?

[gcogger]

I believe you need to edit the config.txt file. Details are here