Ok so I used midi ox to do a bit more investigation.

So the digitakt sends transport start and stop messages just like you’d expect.

The MPK has both a sequencer start/stop and a midi transport start stop. The sequencer start/stop sends no midi when you press it and pressing transport start sends a value of 127 to cc number 117!

So at the moment I have a sequencer that can neither start or stop with an external trigger or start another device that’s waiting for a transport start stop. :frowning:

I have raised a helpdesk ticket with akai…