As Samer said, the software changes pretty rapidly and it’s time consuming for us to make a new SD card image everything the software changes. With the unified firmware, the installation is pretty simple: you just grab the Raspbian image, burn it to SD card, and follow the firmware installation instructions:
https://opensprinkler.com/forums/topic/announcing-opensprinkler-unified-firmware-2-1-4/
the installation should take no more than a couple of minutes.