$('#date').datetimepicker({
        pickTime: false,
        icons: {
                time: "fa fa-clock-o",
                date: "fa fa-calendar",
                up: "fa fa-arrow-up",
                down: "fa fa-arrow-down"
            },
        startDate: new Date()
    });

$('#date').datetimepicker({
    pickTime: false,
    icons: {
      time: "fa fa-clock-o",
      date: "fa fa-calendar",
      up: "fa fa-arrow-up",
      down: "fa fa-arrow-down"
    },
    minDate: moment()
});

You can use this code, by using this code we can avoid additional scripts.
var todayDate = new Date().getDate();
var endD= new Date(new Date().setDate(todayDate - 15));
var currDate = new Date();
$('.datepicker').datepicker({
    format: 'dd/mm/yyyy',
    autoclose: true,
    startDate : endD,
    endDate : currDate
});