Multitasking (iOS)

Multitasking is a feature available on iOS that allows multiple applications to run and perform tasks at the same time. It is available in iOS 4 or later. Multitasking features for iPad were added, including Spilt View and Picture in Picture, since iOS 9.
Multitasking was first released in June 2010 with the release of iOS 4.0. Only iPhone 4, iPhone 3GS, and iPod Touch 3rd generation were able to use multitasking. The iPad did not get multitasking until iOS 4.2 was released in November 2010. Multitasking is currently supported on iPhone 3GS or newer, iPod Touch 3rd generation or newer, and all iPad models.
Features.
Fast app switching.
Fast app switching lets apps to pause and resume themselves quickly and easily change to other apps.An app that is on the screen is "running". An app that is not on screen but is still in memory is "suspended". All apps that are built with iOS 4 SDK support fast app switching if running on iOS 4 and a compatible device. Users can use fast app switching by opening the multitasking bar. The multitasking bar can be displayed by double-tapping the home button.
Task completion.
Task completion lets apps continue a certain task after the app has been suspended. Apps can ask for up to ten minutes to complete a task in the background in iOS 4.0 or later.
Running in the background.
Apps can run in the background by using background APIs. The following are available in iOS 4.0 or later:
The following two APIs were added in iOS 5.0: