After my board shorted due to a Thermal Runaway E1, I’ve downloaded the latest firmware and because I saw that Smart Filament Runout Sensor had been enabled. After clicking that link and being wowed, I ordered one from Amazon. The BIGTREETECH BTT SFS V2.0 Smart Filament Sensor.
It’s a four wire sensor rather than the regular 3 wire, so I guess I can’t use the regular port on the 4.2.7 board.
Where do I plug it in?
Thanks so much! This site is a wonderful resource and well worth the subscription of fifteen dollaridoos 
Chris