About monthly watering: please submit a support ticket with your configurations attached so we can check. We’ve internally tested it and it should be working, but maybe your monthly percentage values weren’t saved correctly.
About weather service provider: DarkSky has become Apple Weatherkit. We’ve been working on integrating Apple Weatherkit. At the same time, we’ve also been working on using AccuWeather, and also we have a contributor who implemented using open-meteo.com. So we have plenty of backup options once DarkSky is offline.
About usb serial: well, each version of OSX seems to change something and it’s always a headache to prepare the documentation to cover all possible OSX versions. I apologize for the confusion.