Under the control of lead designer Jony Ive, iOS 7 will reportedly see a significant overhaul that is expected to bring about new looks for the native Calendar and Mail applications for iPhone and iPad.

Ive is said to be implementing "dramatic changes" to Apple's mobile operating system, according to unnamed sources who spoke with Bloomberg. Specifically, Ive has reportedly eschewed the "skeuomorphic" designs embraced by his predecessor, Scott Forstall, such as the wooden bookshelf look found in the current Newsstand folder of iOS 6.

Skeuomorphism is a term used to describe design elements that are made to resemble real-life objects. Examples of these can be seen throughout iOS, including the felt poker table feel of Game Center, and the leather-like textures featured in the Find My Friends application.

Ive is said to be an opponent of skeuomorphic designs, and reports from last year indicated he planned to remove such elements from iOS. Ive took over Apple's Human Interface responsibilities after Forstall, the previous chief of iOS development, was fired from the company.

Apparent sweeping changes being made to iOS 7 could cause delays, Bloomberg reported on Wednesday, citing unnamed sources. That echoes earlier claims that indicated development of iOS 7 was running behind schedule, prompting Apple to reportedly have OS X engineers pulled from their work to pitch in on the company's mobile efforts.

The report also repeated a detail earlier revealed by John Gruber of Daring Fireball: Those testing iOS 7 allegedly have a special film over their iPhone screens to obstruct what others can see, heightening security surrounding the development of Apple's next mobile operating system.

Apple still reportedly plans to release iOS 7 as soon as September, meeting the company's own internal projections. But deadlines for submitting features for testing are said to be at later dates than past releases.

"Ive is also methodically reviewing new designs, seeking to avoid a repeat of last year's release of map tools that were widely panned, and he's encouraging collaboration between the software and hardware divisions, which operated in silos under co-founder Steve Jobs, people said," author Adam Satariano wrote.

In the cards are said to be even "bigger shifts" for applications such as Mail. But those plans may not be ready for the launch of iOS 7, and could debut in future releases, Wednesday's report indicated.

One future possibility cited in the report is gesture control. It was said that Ive has met with makers of gesture technology, exploring ways that users could control devices by moving their hands and without touching a screen. Such features are not expected to be introduced with iOS 7.