A display system including a display apparatus and an upgrading apparatus are provided along with a control method. A display apparatus includes an image processor which processes an image signal, a display which displays the processed image thereon, a connector to which an upgrading apparatus comprising at least one upgrading function is connected and a controller which communicates with the upgrading apparatus and controls the display to display thereon a user interface (UI) screen displaying at least one upgrading function list generated by the upgrading apparatus in response to a user selection.