I have no idea what all they have done on this update. From the number series, I think its just a small maintenance update, probably some improvements to programming. If it were a major update, the number series jumps up one notch, like to 4.0 instead of 3.0, etc. This is just 3.1.3.
My iPhone went through 2 or 3 series of restarts and runs fine. I cant tell a difference really.
I believe when the iPad launches, we will have a huge (huge) update out for iPhone, since the iPad runs on a basic iPhone OS structure. It may be different, but the structure is based on it. Thus I think that things in the iPad platform will be shared with and expanded to the iPhone and iPod Touch series, probably bringing it to build 4.0. (Thats only my theory there).
I just wanted to let people know about it. Sometimes people do not always synch their devices often and miss the update by a few weeks. (My mom does that, missing two in a row for her iPhone.. All she wants is for it to work the phone and her solitaire card game, lol... )
Bill
LHC