iPhone OS 4

iPhone OS 4 is a major upgrade to the iPhone OS. Again, a bunch of new features, whether or not you will be using it. Some features worth mentioning such as the Apple's way of multitasking. Bad thing is that iPhones older than 3GS will not be able to take advantage of some of the new features.

Notable new features for users include the following:


•Multitasking.
•Spell check.
•Bluetooth keyboard support.
•User-defined wallpaper.
•Tap to focus when recording video, just like with photos, and a 5x digital zoom for the camera.
•Playlist creation and nested playlists.
•App folders for sorting apps! You can even put an app folder in the dock.
•Enhanced Mail with threaded messaging and in-app attachment viewing.
•iBooks, a smaller one.
•And others.
•Game Center for iPhone games like Xbox live.
For multitasking, the following background services are available:
•Background audio.
•Background VoIP.
•Background GPS location data
•Local notifications. (Hmm.... are we getting more annoying ad messages when we are walking around and playing games in the streets? No wonder Apple also launched iAd mobile advertising service)

Some other features for developers to play with:
•Fast app switching.
•iAd. (Apple also want a cut from advertising. Less money flowing to Google AdSense)
•In-app SMS.
•Map overlays
•Quick look for previewing documents.
•Photo Library access.
•Calendar access.
•Full access to the camera.
•Video playback and capture.
•Date and address "data detectors."
•Automated testing and performance / power analysis.
 
Hands-on video available here.