In favor of continuity, and to keep its distinct design, iOS user-interface has appeared largely the same over its 6-year history, with the same rounded-rectangle icons, 3D-appearing UI elements such as buttons, toolbars, and menu borders. With iOS 7, Apple could give the mobile operating system a major design overhaul.
According to a Boy Genius Report article, iOS 7 could feature a new UI scheme that sees flatter objects, and possibly a departure from Apple's fixation with rounded-rectangle objects. There won't be functional changes, so how you interact with the software won't change. Apple won't pull a "Windows 8" off on you. Long time Apple users could still find some changes "unsettling," but nothing that will tickle their learning curve, according some analysts.
We could get a first glimpse of iOS 7 at WWDC (worldwide developers' conference), Apple's annual software developer conference for people and companies flourishing inside Apple's ecosystems. It remains to be seen how Apple distributes the software, whether its design change could affect designs of its existing products. The next generations of Apple products, iPhone 5S, 5th gen iPad, and 2nd gen iPad mini, could all ship with iOS 7 as standard equipment.
In other news, Apple today rolled out iOS 6.1.4 update targeting iPhone 5, with just the one entry to its change-log, "updated audio profile for speakerphone." The update is available OTA (over the air), and could soon make it to iTunes.