Yes, working for me.maybe he can tell us if it's works for him with MP and his 4K HDR TV
I've watched a few 4K HDR movies now (with MadVR / LAV filters & MPAR) and it's just beautiful.
Make SURE you have a proper HDMI cable, at least 2.0a specs with enough bw to transfer the (HDR) video. The most important thing is that it's Premium classified (then it'll work).
A 2160p@60Hz HDMI cable didn't work for me with HDR video.