On big part you should be able to simply drop it in instead of the previous one and everything should simply work. But there are some precautions to take into account. First of all, we’ve dropped BrowserPlus and Gears support, mostly because their authors dropped them themselves. Second point to consider, is the fact, that we’ve renamed .swf and .xap shims, since they are not strictly Plupload specialized anymore (they are now part of pollyfills and not the Plupload). So in the places where you reference plupload.flash.swf and/or plupload.silverlight.xap, you must now put correspondingly - Moxie.swf and Moxie.xap (as these are the names of updated shims).