The iPhone 5S', along with the iPhone 5C's, release date may happen on September 10 in the U.S. and on September 20 in Japan.

Japanese news Web site Nikkei stated that the iPhone 5S and the iPhone 5C will land in Japan on September 20. There were also previous reports that claimed that the upcoming iPhone 5S will arrive in Greece on September 20. Thus, it is speculated that September 20 is the worldwide release of the upcoming new iPhones.

Based on previous iPhone releases, the handset is made available a few days after Apple announces it. In the case of the iPhone 5, which was released last year, it arrived 9 days after it was announced. Thus, a worldwide release on September 20 is not impossible.

Another evidence that hinted the iPhone 5S release date will happen on September is the imminent release of the official version of iOS 7. According to reports, Apple is bound to release the seventh and final beta version of iOS 7 soon, which will contain the final tweaks and updates of the Apple OS.

The Gold Master version of the iOS 7 is pegged for release on September 10. However, the iOS 7 Beta 6, which boasts a whole new look as well as features, is now available for download.

The full-fledged iPhone 5S is expected to replace the current iPhone 5 with upgraded design and features. It is speculated that the iPhone 5S will include specs such as A7 quad core processor, iOS 7, up to 128 GB internal storage and fingerprint sensor in the home button.

Meanwhile, the cheaper iPhone of the company dubbed as the iPhone 5C may include a 4-inch screen display, dual core processor, 8 MP rear shooter and a plastic casing. It will bear a tag price that will compete with cheap Android-based smartphones.