Supersede?

I was told that the part number on the gas valve in my unit has been superseded. Im not sure what that means and was hoping that someone had a little more info for me.

Hello, The definition of supersede can be found below:

take the place of (a person or thing previously in authority or use); supplant.
"the older models have now been superseded"

This means that your part has been replaced by a new part number. Therefore, you would need to purchase the new part number.