I have a spare Passport I/O control. It has firmware version A12. It seems to work "ok" with my 2-year old SCM 16K MarineAir unit. My other unit, a 12k version, is running "better" with the supplied Passport control, which has the A22 version of firmware on it.
I got the older controls (two of them) from the used nautical supply place (can't remember the name of the place!) in St. Augustine last year. Sometime between unboxing the two A/C units when I bought them and actually installing them, I misplaced one of the new controls, so I just bought a couple used.
The problem I'm having is that the larger 16k unit constantly will error out and display "HPF" (high pressure freon), which is usually an indication of blockage or reduced flow in the cooling water
circuit. I plumbed both units off a single
3/4" thruhull, which may be the problem...
I think he just wants to know the version of the control board in the A/C unit so he can match it with a Passport control with the proper version of firmware. Of course, it would be simpler if he just told you that initially...
Let me know if you want to try it. The boat's in Hampton, VA right now.