How to dynamically change the datepicker range?

Datepicker library I'm using: GIJGO

I'm trying to change the minDate inputs of the datepicker library depending on which option is selected by user is a drop-down menu. The options of the drop-down menu are as follows:

<select class='form-control mr-2' id='idType' name='idType' placeholder='Select' required>
<option>UserID</option>
<option>UID</option>
<option>All Records</option>";
</select>

HTML:

I am trying to set the minDate of the datepicker to be 2 months from today if "All Records" is selected. Otherwise the minDate will be '2019-11-18'. The datepicker is stuck on '2019-11-18' and will not change to 2 months prior with my if statement. What am I doing wrong?

$(document).ready(function() {

var today = moment().format('YYYY-MM-DD');
var pastMo = moment().subtract(2, 'M').format('YYYY-MM-DD');

getDatePicker('2019-11-18', today);

console.log(pastMo);

$('#idType').change(function(){
   if($(this).val() == 'All Records'){
      $("#idSearch").prop("disabled", true);
      getDatePicker(pastMo, today);
    }
   else {
      $("#idSearch").prop("disabled", false);
      getDatePicker('2019-11-18', today);
   }
 });
});
function getDatePicker(min, today) {
$('#start_datepicker').datepicker({uiLibrary: 'bootstrap4',format: 'yyyy-mm-dd', minDate: min, maxDate: today});
$('#end_datepicker').datepicker({uiLibrary: 'bootstrap4',format: 'yyyy-mm-dd', minDate: min, maxDate: today});
}

Code (JavaScript):

Thank you for any tips or suggestions!