If you calling the different versions of Jquery then your code can clash the mutual variables. To use each of the Jquery versions separately you have to use " jQuery.noConflict()"

Consider the links with multiple Jquery versions below:-

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js" type="text/javascript"></script>
<script>
    var $i = jQuery.noConflict();
    alert($i.fn.jquery);
</script> 

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script>
    var $j = jQuery.noConflict();
    alert($j.fn.jquery);
</script> 

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script>
    var $k = jQuery.noConflict();
    alert($k.fn.jquery);
</script> 

So by this way you can have as much as versions of Jquery that you need.