Apple is releasing a second major refresh of its mobile operating system, iOS 8, next week.

The software will have an improved messaging system and sync better with desktop devices and the cloud. It will be available for the iPhone 4 model and newer.

While the iOS 7 major software update focused mostly on visual changes, CNET says iOS 8 is expected to have major changes in functionality.

In the iOS update, Apple is fixing the notification system glitches, tie-ins with Apple's desktop OS X software and iCloud, and updating its native SMS client Messages, among other updates, according to CNET.

The iPhone will also be more compatible with other Apple devices after the update. A new addition called Handoff will let users start a task, such as composing an email, and finish it on another device.

The iOS release date is Sept. 17.