The comment at the bottom sums it up (though they snuck in the CAB M+ update since then)
"21 juin, 2019
Hello Brandon,the difference between the firmware currently in the C.A.B. M and the Wall of Sound is the C.A.B. M uses dual miking on each cabinet, whereas WOS is one mic per cabinet. Also WOS can do stereo whereas the C.A.B. M is a mono unit. This is not a minor update for the software team, as it is not about only updating the Remote but also the firmware of the C.A.B. M. We are looking to raise the compatibility between all the units and software, but this is a very lengthy process. Kind regards."