Android box running 7.1.2 - no option to select Optical Out?

Jul 15, 2018
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Hi guys, any help greatly appreciated - while I still have a few hairs left!

My system worked fine with my old Android box, using the optical (spdif) out, having selected this option from within Android settings. My new box runs Android 7.1.2 and I can see no way to select optical as my audio output. It has main settings and also "droid settings" within the apps but this option is unavailable in wither... Any ideas?