Sometimes you find yourself in a situation where you need to use a new version of jQuery but the project already uses an older version and you're not at liberty to just update it. It's possible to use multiple versions of jQuery in the same document.
This just requires the use of jQuery.noConflict() in combination with closures. This way, it is very clear what you're doing and you won't have to refactor all of your jQuery code.
Please remember that although it is possible to do this, and even include more versions of jQuery, including so many versions is a big performance hit, so I wouldn't recommend it.
First you'll include the new version of jQuery and assign it to a variable.
var jQuery18_1 = $.noConflict(true);
Then you'll include the older version. It will overwrite the $ variable.