Why are XP users stuck on IE8? (I mean I think there are a myriad of options that are pretty reasonable). It doesn't cost anything or fairly little labor to upgrade to a real browser over the course of a couple years. How far do we take this, why don't we all support IE5? It's time to let it go.

You can either stick with JQuery 1.9 for as long as you want to support IE8 (hopefully not more than 10 or 20 more years).