If your program directly calls the File Handler API (also referred to as the Callable File Handler), then you would have had to directly code an FCD block. If the program codes an FCD block using the FCD2 format (or relies on the xfhfcd2.cpy copybook), it will need to be modified to use the 64-bit FCD3 format instead (as defined in the xfhfcd3.cpy copybook); see File Control Description (FCD) for full details of the required format.