Modern buttplug.io uses websockets to talk to a service. That service talks to the actual devices, so you don't need to worry about the exact protocol. It should work for anything (and can be updated without any effort on your part). So it has a configurable IP and port.
If you'd like some development help (and are comfortable sharing source with a stranger on the internet) I'd def lend a hand getting up and running with it.
Did a bit of digging.
Looks like IntifaceCLI.exe is packaged with the game.
Intiface can read configuration files. How is this done in game? What is the command-line?
I've seen people use an IntifaceCLI.bat to add configuration that is easy for users to change, if "IntifaceCLI.exe" is replaced with "IntifaceCLI.bat" (which just runs IntifaceCLI.exe) that might work.