We'll respond shortly.
A plugin introduces a regression. Wait to upgrade jQuery 2.0.x.
It's out! And it dropped support for IE versions > 9!
Full release blog post here: http://blog.jquery.com/2013/04/18/jquery-2-0-released/
Also, as JT had mentioned, there is a security hole that was introduced in 2.0. Hold off until this is fixed!