We’ve just released an improved version of OS 3 (the minor revision number is 3.2) that can optionally come with an Ethernet module. It’s already available on the product page:
https://opensprinkler.com/product/opensprinkler/
You can add wired Ethernet module to the controller.
Besides, even without the Ethernet module, you can use a pocket wifi router to allow OS 3 to interface with wired Ethernet, this is described here:
https://rayshobby.net/docs/os30_wired_howto.pdf
OS 2.3 and 3.x are both actively supported, including firmware support. OS 2.3 does NOT support upgrade over the air. OS 3.0 or above does.