Discovered yesterday - the awful breaking changes from libgpiod-dev v1.x to v2.x. I had written code that works on the RPI4 and some other random SBCs, but discovered yesterday that it doesn't compile on the RPI Zero. Surprised to find that the RPI Zero has a newer version of libgpiod-dev. I got things working again with some #ifdef's, but still surprising how they completely broke backward compatibility.