@jasonINmadison I may be wrong about the neutral. The installation diagram for the tapo switch shows 4 wires; 2 hots, a neutral, and a ground. There are 2 wires (black & white) to the existing...

My house was built in the 1930s and does not have a neutral or ground wire for light switches. Can I use the S500 or S500D with no ground wire?