The last-week-unveiled Apple iPhone OS 4.0 boasts a number of new features and changes, the most notable among them being – multitasking; home screen wallpapers and folders; a 5X digital zoom on the camera; an uodated Calendar icon on the home screen; and a unified mail inbox.

Interestingly, there is also a change in the blue search button of the Safari browser – it now says “Search”, instead of saying “Google by default.”

The most noteworthy of the new features is multitasking, which allows users to run a number of third-party apps at the same time. Users can access the multitasking bar, which indicates all open apps, by tapping the iPhone’s physical home button twice.

The improved video capabilities and the enhanced camera are also among the significant improvements included in the new iPhone OS. The digital zoom of the camera allows users to zoom in up to five times on an image; while a tapping on the screen allows them to focus while using the video camera.

A host of changes in the iPhone OS 4.0 facilitate the searching and organizing process for the users. The Calendars app, which earlier turned off and on all accounts, now allows users to select different accounts. In addition, the Messages app now features a search bar; and all key apps – including Notes and Messages – now boasts a spell checker integration.