After some checks u.s. sites, Microsoft confirmed that the sound output to One Xbox support as the only format for DTS surround sound and that, at least for now, the Dolby Digital 5.1 format is not supported. This shouldn't pose a problem for audio home theater systems which of course decode the DTS, but it could be to surround the headset.

This is because different models of headphones, especially the cheaper, do not support DTS but only the DD 5.1: in this case wouldn't be able to play the positional audio by transforming it into a stereo signal.

No problem for the audio sent through HDMI, which supports the DD because the DTS; It is not known however for now if and when Microsoft will release an update to make it compatible with only-Dolby Digital optical output too.