First Look: Apple's iOS 4 for iPhone, iPod touch

By Daniel Eran Dilger

Apple is celebrating the summer solstice this year by making the next major reference release of its mobile operating system available, for free, on Monday June 21st. The new iOS 4 will provide existing iPhone and iPod touch users with a system-wide upgrade and pave the way for the iPhone 4 launch on Thursday.

Apple's iOS 4 provides a variety of new and enhanced features on a core OS level, on a developer API level, and on the surface for end users. Some of these features are limited to new hardware in the latest iPhone 4 (such as FaceTime video calling), while others are only available on last year's iPhone 3GS and third generation iPod touch (including multitasking).

iOS 4 is not supported on the original 2007 iPhone and iPod touch models, and can't be installed on iPad. Apple says a later release this fall will bring iOS 4 features to iPad users, much like the special iPhone OS 3.2 that was exclusive to the iPad at its launch. For all other iOS device users, iOS will be made available for immediate download as a software update within iTunes; that's an distinct advantage Apple holds over most other smartphone platforms, where users might wait months for a new software update to be made available by their mobile provider and for their specific phone model.

iPad features for other mobile devices

iOS 4 delivers a number of features from iPhone OS 3.2 (as it was called upon its release), which debuted on iPad this spring, to iPhone and iPod touch users. These include:

On page 2 of 3: New user features in iOS 4.

New user features in iOS 4

The new release also ushers in new features that aren't available on iPad and won't be until Apple delivers a custom release for it this fall. These include:

On page 3 of 3: New features for developers.

New features for developers

iOS 4 adds a lot of under the hood plumbing for third party developers to exploit in their apps, along with general core OS features that enable new functionality and make the system faster and more robust. Apple claims 1500 new APIs for developers in iOS 4. Many are rather esoteric, but there's a few that are very visible to users: