Of course, we're hardly going out on a limb there: Apple already , at its Worldwide Developers Conference, where it showed off a handful of new major features and alluded to dozens of smaller improvements.

New details about the OS update that we didn't see in June may get some time in the spotlight Tuesday. But just to make sure that you're caught up to speed by the time CEO Tim Cook takes the stage Tuesday at 10 a.m. PT, here's a refresher on what Apple has planned for iOS 5. (For an even deeper dive, consult our from June.)

The most-hyped and most-awaited improvement in iOS 5 is probably , which has gotten a significant overhaul since push notifications were . No longer are you limited to those blue modal dialog boxes that pop up when you're inevitably in the middle of something important.

There are several different parts to iOS's new notification approach: