AppleInsider has been taking a look at the newly released iOS 5 beta 6, and discovered that some changes have been made to the way in which apps are updated on the app store, i.e., individual apps can now be updated in the App Store without you automatically being thrown out of the App Store to the home page to watch that little green bar on the updating app icon slowly creep along as the update takes place. Now, according to AppleInsider, after clicking the Update button in the app store, the app will be updated in the background, and instead of seeing that little green updating bar, you’ll see a greyed-in Installed label on what was the Update button. AppleInsider says that this feature also works when you update an app via the Purchased menu. The one exception to this welcome new change is if you click on the Update All button, when you will be thrown out to the home screen as is currently the case in iOS 4.
Source: AppleInsider | Inside iOS 5: Update apps in place within iOS App Store