I didn’t know that. I have the MarkV-25, which has it. Although I bought mine like 6 months before the JP2C was introduced. i only have two channels, which is limiting, so I’m keeping my TriAxis for clean tones in the rig as a 3rd channel. They sell the CabClone as a standalone unit, and it seems to get consistently mediocre reviews, which I really don’t understand, because the one built into my MarkV sounds great 9or at least good enough) on monitors for recording and late night playing on headphones.
Another option, FWIW, if you have a computer or DAW connected to your guitar rig, it to take the preamp loop out of your MarkV, then DI (or split) it into a DAW running either Amplitube or similar, and ONLY use the latter to add speaker cabinet emulation. I use the H9000 via ADAT to connect to my DAW (I have a digital mixer in the middle conveniently but not required) so the H9000 can be used to connect analog (Switchblade) and digital (Amplitube cab emulation) and do serial/parallel loops at will. But this would require that your MarkV can turn off its own speaker cab while keeping at least the preamp on. I dont know if it can do that, so the above may not work.