Sorry about the confusion. Because very few users take advantage of the relay, and it’s kind of expensive, we’ve made the decision to remove the relay from all OpenSprinkler hardware (including OS, OSPi, and OSBo).
Also, due to a recent supply chain problem of ATmega644, it turns out that buying ATmega644 ends up costing more than ATmega1284, that’s why we decided to upgrade to ATmega1284 ahead of schedule. I will try to check in the schematic this weekend.
You are right that you can still add your own relay to use the feature. Unfortunately I realized that when removing the relay, I didn’t add the corresponding digital pin to the pin out area. So that microcontroller pin is not mapped out. At this point, your best option is to modify the pin definition (in defines.h) to use any other available pin, and recompile the source code.