As Apple will start distributing the new iPhone operating system, iOS 4 as of the 21st of June, iPhone users are going to need applications that are compatible with iOS 4 to start hitting the App Store, and the most notable feature that needs support is iOS 4 is multitasking.

According to an article over on Macrumors by Arnold Kim, by way of AppShopper, a prominent application in the App Store which supports the basic iOS 4 multitasking API is an application called Dropbox which is apparently a file syncing and sharing tool.

Apple has introduced 7 precise background services for iOS 4 applications which will enable them to do tasks after a user moves away from them and those 7 are…Background Audio, Background Location, Local Notifications, Push Notifications, Voice over IP, Fast App Switching and Task Finishing.

Fast App Switching is the most notable which should be implemented is all iOS 4 applications as it allows the user to switch in and out of an app without the need to restart said app, and apparently Dropbox looks to support the Fast App Switching feature.