Hi Ted.
The image is actually a raspbian jessie image, which updates using the default picroft version. I just use a newer kernel version, to enable the aiy, and adjusted some config files. The problem is that the new rpi seems to use raspbian stretch. Mycroft does not work properly on stretch, yet… I came across dependency problems, and weird ssl errors when installing it on stretch.
It seems I am not the only one: Raspberry Pi 3 Model B+ Compatibility?
Not sure how you would be able to get it working yet.
This thread has all the configuration info you need for the AIY: PiCroft issue with pairing
Good luck,
Tjoen