As a homeowner, you should reset the opener to prevent outsiders from opening the door with a remote that's set to a Liftmaster default code. A simple procedure allows you to reset the opener for one or more remotes.
doorsill - the sill of a door; a horizontal piece of wood or stone that forms the bottom of a doorway and offers support when passing through a doorway. doorstep, threshold. 1  doorway, room access, door, threshold - the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close; he stuck his head in the doorway.
(USA answer) The bottom of a door frame is usually called the threshold or doorsill. A sole plate is the first piece of wood that lays flat on its widest face at the bottom of a stud wall. Studs (usually 2x4's or 2x6's) rest vertically on the sole plate. It may be made of pressure treated wood to prevent decay or a specie that resists decay naturally such as cedar, or cypress, or redwood. Corrected in this answer: The plate that rests on top of a foundation wall is called the sill plate (not sole plate).