<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="js/bootstrap.min.js"></script>    
<script type="text/javascript">
	function toggleIcon(e) {
    $(e.target)
        .prev('.panel-heading')
        .find(".more-less")
        .toggleClass('fa-plus fa-minus');
}
$('.panel-group').on('hidden.bs.collapse', toggleIcon);
$('.panel-group').on('shown.bs.collapse', toggleIcon);

</script>