At first it did but it never has shown the upfiring speakers. Once it rebooted then it showed it like a 5.1 config like I have. There are 3 boxes you have to check for dolby atmos. I'm not at home but I think one of them was under advanced setup under the properties tab for speakers. Also my AVR displays dolby atmos when it's working.
Yeah, my receiver says "Atmos" but youtube and MP3's only use the front L+R speakers.
My receiver can upmix stereo to all channels but with Atmos enabled in Windows 10 then the receiver loses this ability. Basically with Atmos enabled I'm still getting stereo as an Atmos signal.
Can you let me know if your Atmos is using all the channels for music?