I don't know, LMQ. I could have sworn they were but when I press the info button on the remote the OSD says 4.0 input.My gear doesn't either. But if I pass a 4.0 file to my son (Pioneer 7.1 AVR), it plays in stereo with only 2 of the 4 channels.
My point is, why doesn't Rhino format Quadio releases as 5.1? Same issue with quad floyd inside the immersion box sets I believe.
Still have an older Onkyo that won't play 4 channel without adding at least a silent C but it's not used these days. I mean it's not ancient, it's 5.1.2 Atmos capable so I guess about 2016.