Someone mentioned that “The latest OSPi runs on IPv6 exclusively” — this is NOT correct — the firmware creates dual IPv4 and IPv6 ports, so it should work with either IPv4 or IPv6.
The only issue we are aware of is users who installed OSPi firmware originally by using the pre-configured SD card image that we created a couple years back. The Raspbian system on that SD card image is out-dated and can’t support dual IPv4 and IPv6. We will update the instructions to remove the pre-configured SD card image. But the solution is to install the latest Raspbian and then install OpenSprinkler firmware according to: