There are generally two ways to make software customization: if you have experience with microcontroller programming and can get the source code to compile, you can modify the firmware yourself; otherwise you can also use an external script (like Python, Javascript etc) to interface with the controller via the firmware’s HTTP API calls. For example, you can modify the watering percentage, or each zone’s water time by using HTTP API. This does require another computer or server to send commands in real-time to the controller, but you can do it in a variety of ways like using a cheap Raspberry Pi.