A minor update to the 1.6 version of jQuery was just released today. After a big outcry of version 1.6's changes to the way properties work, the jQuery team quickly released version 1.6.1 to make the new techniques more compatible with the older functionality, hopefully preventing sites from breaking. The release also fixed some bugs, as did version 1.6.2.
And now 1.6.3 also fixes several bugs, along with one change that some people will find disappointing: They dropped support for the requestAnimationFrame API. When 1.6 came out, support for requestAnimationFrame was added to allow for smoother animation. However, requestAnimationFrame itself has some issues, and as a result it didn't carry forward very well into jQuery. People were reporting problems with the way some animation would wait to occur, and then would run through the whole sequence at an extremely fast speed. (They called it a wormhole.) So the jQuery team decided the jQuery world would have to wait, and they completely dropped requestAnimationFrame from jQuery. They're hoping they can re-introduce it after they get the kinks worked out. (Of course, requestAnimationFrame is still there, just not a part of jQuery, so you can still use it yourself.)
In addition, there are a few minor fixes. There's a security fix to help prevent script injection. When you precede a selector with a # (which is used for specifying IDs), the jQuery library won't allow HTML tags to be in the selector. The whole list of bug fixes is pretty long for a minor release, and some of them fix situations where the browser actually crashed. For example, here are two bugs that have been fixed. (I'm copying the bug report titles verbatim):
"$.inArray crashes IE6 and Chrome if second argument is null or undefined"
"IE 8 crashes when using background-image on BODY in css"
All in all, you shouldn't have to make any changes to your jQuery code if you were running with 1.6.2 or 1.6.1. For details, see the official jQuery blog posting, as well as a link in that posting to download the new version.