Installed as per tutorial here https://opensprinkler.com/forums/topic/tutorial-install-opensprinkler-unified-on-a-fresh-raspbian-image-for-a-pi-2/ and it works.
The OS image and the docs could use an update though, as for the new user it isn’t very clear where to start. Normally the easiest way to go is to download a pre-configured image, which in this case doesn’t contain required kernel and latest software.