Apple iPhone 5S rumors
AT&T cancelled employee vacations for the second half of September, seemingly in preparation for the iPhone 5S launch on Sept. 20. Reuters

While rumors are rife that Apple (NASDAQ:AAPL) could release the next-generation versions of its flagship smartphone -- the iPhone 5S and the iPhone 5C -- on Sept. 20, a report on Thursday said that AT&T (NYSE:T) has blacked out employee vacations for the second half of September, apparently in preparation for the launch of the new iPhones.

The news has come from BGR, saying that AT&T, which took a similar step last year ahead of the release of the iPhone 5, will not be releasing any other major handsets from other manufacturers during the second half of September, suggesting that the upcoming iPhones could indeed arrive in the highly anticipated time frame.

iphone-5s-champagner-gold
Apple iPhone 5S rendering in champagne/golden color. Shope le Monde

The BGR report came just one day after T-Mobile reportedly canceled vacations for its store employees between Sept. 20 and Sept. 22, the weekend when the iPhone 5S and the iPhone 5C are expected to go on sale.

Blacking out employee vacations is a move by major U.S. carriers supposedly meant to ensure enough staff is available to handle an overflow of customers looking to get their hands on the new version of a product such as the iPhone.

Apple is very likely to announce the next-generation iPhone 5S and the so-called low-cost iPhone 5C at a special event on Sept. 10, with a launch expected to take place 10 days after that.

The iPhone 5S, the successor to the existing iPhone 5, is rumored to feature a fingerprint sensor embedded in the traditional home button, an A7 processor that is 31 percent faster than its predecessor, motion-tracking capability and an upgraded camera with a dual-LED flash component.

In addition, various reports also point to new "champagne" and “graphite” color options for the iPhone 5S. Take a look at the videos here, courtesy of TLD and BestTechInfo, which provide a detailed look at the casings of both "champagne-" and “graphite-” colored iPhone 5S.

The iPhone 5C, on the other hand, is expected to sport a plastic shell, which is rumored to be offered in multiple color options. And while not many details are available regarding the handset’s internal specifications, some earlier reports have claimed that the device will feature the same 4-inch form factor of the iPhone 5, but with relatively older components, which will help keep its cost down.