Hmmmm will lay of this one for a while before updating the 4 devices in our household. See if it breaks anything..
Oh and as to those who say you can always choose not to update, well, yes you can, if you accept the big message every time you unlock your device telling you to update!! And this is after the 24 hours roll back time expires.
So I wonder how many people do update when they see that, realise it makes their device really really slow or breaks something and they cannot uninstall it, and Apple gloats how many people are on iOS version whatever!