It only works with a few new models. I have a 1DX III, 1DX II, 1DX, and 5DS R and it only is functional with files from the 1DX III. I haven't found it to be very useful so I don't think you are missing much.
Although the 1DX III uses the same resolution sensor as the 1DX II, processing its RAW files is much more computer resource intensive so a lot changed with what it is doing with files.
Rodger
EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video
