Xfinity Home wired into old security panel

When I had Xfinity Home installed - the technician was able to wire it into my old security system.  One of the sensors is in my from door.   I'm having my from door replaced, and the door frame which holds the old security sensor is going to be removed.   When I called Xfinity Home they said that they can just send me a new wireless sensor, but will the Comcast wireless sensor connect directly to my Xfinity router or will it try to connect to the old security system (which is not wireless)?