I tried to update it again today just after 12.00pm and it worked! My Denon AVR-X3200W is now DTS X capable. Just gave it a test run with Whiskey Tango Foxtrot on Blu-ray. It worked just fine. Wasn't a great soundtrack though.
I have been able to answer my own question. Yes the local disc does indeed have a DTS X soundtrack. My local Videoezy got them in today, so I bought a copy. While I was doing that, my Denon receiver was downloading the DTS X firmware. I am a little disappointed by the soundtrack. The overhead speakers are used more to support existing sounds rather than many discreet sounds of its own. It is not as good as the Dolby Atmos tracks on Terminator Genisys, Everest & The Man From UNCLE, for example!
The review of the LG B6 Oled by rtings scored it 9.2/10 for motion only making it down for judder on 60p and 60i material and scoring it 10/10 motion blur and 10/10 motion interpolation. http://www.rtings.com/tv/reviews/lg/b6