Marshmallow 6.0.1 upgrade just been made available for the Xperia Z3c so I thought I'd give it a go and see how Mini Connected performs.
Factory reset the phone first to clear down any of my rubbish, then upgraded, and factory reset again.
Installed apps inc Connected and Journeymate XL. Started these up (and registered) to ensure working before connecting to car.
Removed phone Bluetooth profile in car, re-added and checked phone connection (contacts, calls, audio, etc) working OK
Reconnected phone to USB socket - Mini Connected starts automatically on phone and all functions available on car display. Disconnected USB, added a destination to Journeymate, reconnected USB and trip list was updated in car Journeymate.
Sorry the above is a bit long, but hopefully others can benefit from it. I'll carry on playing over the next week or so and report back if any issues arise.
(just to confirm versions:
Phone - Xperia Z3c compact
Android - 6.0.1
Mini Connected app - 1.1.3 (row_160214_449)
Journeymate app - PROD_ROW 1546: 2.0.0.1013
Mini software update - UPD5073 (Media XL = MN-002.255.071, TN-002.255.070)
)