A method for modernization of an elevator installation with several elevators in a building, wherein at least one floor terminal for input of a floor call is provided on at least one floor of the building, which floor terminal is, for communication of an input floor call, connected with a group control, and at least one elevator is controlled in drive in accordance with the communicated floor call by the group control, includes connecting at least one call detecting unit, for communication of an input floor call, with the group control. At least one new floor terminal is, for input of a floor call, mounted on at least one floor and the new floor terminal is, for communication of an input floor call, connected with the call detecting unit.