Found:
administrator/components/com_virtuemart/helpers/vmjsapi.php
Before:
self::addJScript('datepicker','
jQuery(document).ready( function($) {
$(document).on( "focus",".datepicker", function() {
$( this ).datepicker({
changeMonth: true,
changeYear: true,
'.$yearRange.'
'.$minMax.'
dateFormat:"'.$jsDateFormat.'",
altField: $(this).prev(),
altFormat: "yy-mm-dd"
});
add:
$yearRange = 'yearRange: "1918:2018",';
$minMax = 'minDate: "-100Y", maxDate: "+1Y",';