iPhone OS 4.0: Multitasking, folders, home screen, iBooks, rich ads

Apple today announced the release of iPhone OS 4.0, the next generation operating system for its line of mobile devices. Scheduled to ship this summer, with a developer preview available today, OS 4.0 adds 1,500 new developer APIs and 100 new user features to the existing iPhone OS platform. The OS 4.0 update will be fully supported on the iPhone 3GS and third-generation iPod touch models, while the second-generation iPod touch and iPhone 3G will support “many” but not all of the new features. Prior-generation devices, including the original iPhone and iPod touch, will apparently not support iPhone OS 4.0 at all. The initial release of OS 4.0 will be for the iPhone and iPod touch platforms only; an iPad release is expected later this fall.

During the announcement, Apple specifically discussed and demonstrated seven major new features that will be introduced in OS 4.0: Multitasking, Folders, Enhanced E-mail, iBooks for iPhone/iPod touch, Enterprise Features, Social Gaming, and iAds. In short, the features enable background music from applications such as Pandora and background turn-by-turn GPS directions from apps such as Tomtom, folder organization of apps, unified e-mail inboxes and threaded discussions, a customizable Home screen background, greater device security, online matchmaking for games, and “emotional” advertising. The features will depend in some cases on iTunes 9.2, which will presumably be released alongside the new OS in Summer. Click on the title of this article for detailed discussion of all of these features, and more. Apple’s official press release announcing iPhone OS 4 can be seen here.


iPhone OS 4.0 adds long-awaited support for allowing specific third-party application services to run in the background. Since battery life remains a concern, Apple has chosen to expose limited multi-tasking via specific APIs rather than simply keeping every app running in the background. Applications will need to be specifically updated to take advantage of the new multitasking features in OS 4.0 and to run their services in the background.

The multitasking interface is accessed by double-clicking on the Home button, which will reveal an Exposé-like interface from which other background-running apps can be selected. The UI looks like an extension of perforated background standard dock.

iPhone OS 4.0 will allow seven types of services to run in the background via specific APIs:

Background Audio: Applications such as Pandora will be able to keep playing music even after switching away from the app. Music will continue playing in other applications in much the same manner as the iPod application currently does. The standard pop-up iPod controls can also be used on the lock screen to control playback in Pandora and other supported applications.

VoIP: VoIP applications can now stay online in the background so users can receive calls while using other applications or while the iPhone is locked at the home screen. An incoming call notification will appear similar to the one used for a normal incoming cellular phone calls.

Background Location: Applications can remain running in the background to update location data while the iPhone is off or the user is in another application. This will allow turn-by-turn GPS applications to continue tracking location for navigation purposes and still provide voice directions even while in the background. This can also be used for social networking applications such as Loopt to continue updating location information on the go. To save on battery life, social networking apps will use cell tower triangulation to determine whether a user’s location has changed sufficiently that a more detailed GPS update is needed. To account for the privacy concerns with background location services, OS 4.0 will provide an indicator on the status bar to let users know if any app is asking for their location. Location services can also be enabled or disabled on a per-application basis.

Local Notifications: Application will now be able to generate local notifications without relying on an external server or a data connection. This will be particularly useful for scheduling and task management applications that need to generate local alarms. Previously developers of these apps have had to either set up a Push Notification server or implement subscribed calendars merely to provide users with notifications.

Task Completion: Applications that are in the middle of a task, such as uploading photos to Flickr, can remain resident in the background in order to finish processing the current task.

Fast App Switching: Applications can now instantly resume exactly where the user left off without needing to worry about saving state before exiting.

Folders on Home Screen

iPhone OS 4.0 finally allows users to organize their home screen applications into folders. Users can create new folders simply by dragging one app on top of another, and folders can be renamed or added to the dock. The addition of folders increases the number of applications available on the iPhone home screen from 180 to 2,000.

Enhanced Mail application

Apple also announced some major enhancements to the built-in Mail application. New features include a unified inbox for viewing mail from multiple accounts in a single list, support for more than one Microsoft Exchange account, the ability to organize messages into threaded conversations and to open attachments in other applications directly from within the Mail app.

iBooks for iPhone OS

OS 4.0 will also include support for iBooks for the iPhone. The application will appear much the same as it does on the iPad, and iBooks can be purchased from either the iPhone, iPod touch or iPad and synced to other devices through iTunes. Pages and bookmarks will synchronize wirelessly across devices in much the same way that Kindle’s WhisperSync technology works.

Enterprise Features

Apple also announced a number of new features targeted toward expanding the role of the iPhone in the enterprise space. New enterprise features include improved data protection, with the ability to encrypt all mail and attachments with a PIN code and an API to allow developers to encrypt in-app data as well. New Mobile Device Management features are also being introduced to better facilitate mass iPhone deployments in large organizations, and Wireless App Distribution will allow enterprise IT departments to send out custom apps via their own servers rather than relying on iTunes. Support has also been added for Microsoft Exchange 2010 and SSL VPN technologies from Juniper and Cisco.


Apple announced plans to create a new social gaming network similar in concept to the Plus+ and OpenFeint networks. The social gaming network will provide support for challenging friends, automatic match making based on skill levels, and online leaderboards. During the Q+A session, Scott Forstall indicated that Apple’s goal is to unify users on a single social network so that they can easily connect with their friends.

The new social gaming network is expected to be supported in OS 4.0, but will not be fully deployed until later this year. It is being shown under the name “Game Center.”


The last major new feature Apple announced was support for a new mobile advertising platform to be built directly into the iPhone OS. The iAd platform will allow developers to display mobile ads through APIs in the iPhone OS rather than having to build their own in-app advertising solution. Jobs noted that the goal is for developers to keep free apps free by providing alternate monetization incentives. It is also hoped that the quality and interaction with the ads will be improved by this process, and that users will be able to view and access ads without being taken away from the current application in the process.

Other New Features

Although not specifically elaborated on, several other new features were also announced for OS 4.0. New features include support for sending SMS messages from directly within an application, the ability to create new playlists directly on the device and a 5x digital zoom in the camera app along with tap-to-focus for video recording. OS 4.0 will also add some iPad features such as Places support in the Photos app, the ability to set a wallpaper on the Home Screen and a built-in spell checker.

Further, developers will now have new APIs available for accessing calendar information, the photo library and both still and video camera data. Developers will also have access to the same automated testing tool used by Apple.

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