Apple Insider published an in-depth review of iOS 5

At the center of Apple's iOS platform is the App Store. Developers' existing apps not only continue to run on the new iOS 5, but also automatically take advantage of many of its new features, such as the ability to select and define words in text or compatibility with the new notifications system described below.

The other changes developers must make to ensure their apps are iOS 5 savvy are relatively minor, promising another smooth transition for iOS users who have already weathered two major reference releases without significant problems.

In addition to general embellishments that run throughout iOS 5 that developers can take advantage of, ranging from AirPlay wireless video to Accessibility features to Twitter integration, Apple has also added Newsstand, a way to show off periodical app content. Subscribe to newspaper or magazine apps, and they now appear in an iBooks-like shelf interface and update in the background as new issues became available.

  In-depth Review: iOS 5