upmix

TL;DR: Are AV receivers / AV amps that upmix from 5.1 --> 7.1 still a 'thing'? I have googled av amplifier with 5.1 upmix av amplifier with dolby IIx etc. Most of the stuff that comes up seems out-of-date, and I can't find any currently available AV amps that advertise Dolby Pro Logic IIx. So...