Comment 16 for bug 1636838

No, there's no special process required:

-take the rpi2 image: http://cdimage.ubuntu.com/ubuntu/releases/16.04/release/ubuntu-16.04-preinstalled-server-armhf+raspi2.img.xz

-enable proposed, and do a dist upgrade and you'll get all the above packages

-reboot

-does it come back? yes, fine -> verification-done