If you're planning on lining up in August to get the next iPhone you'll be waiting for a long time -- or at least several weeks. Apple has reportedly blocked its retail staff from taking time off in September, which fits with the company's usual new iPhone launch window, and falls outside the rumored August release.
The German website ifun (English translation) said employees at local Apple retail stores have been told they can't take extra time off in September, hinting that the company is sticking with its usual fall schedule for rolling out new iPhone models.
Rumors have claimed Apple would be releasing a 4.7-inch iPhone model in August, and following up with a 5.5-inch model a few weeks later. Without any employee leave blackout dates in August, however, that seems very unlikely.
What seems more plausible is that Apple will introduce a bigger screen iPhone in September, most likely 4.7-inches, and there won't be any mention of a 5.5-inch model. Rumors also say the new iPhone will sport a redesigned body that matches the iPad mini and iPad Air. Reports that Apple will add NFC (Near Field Communication) support have cropped up again, too, although the company hasn't shown any interest in the technology so far.
Apple isn't talking about what's in store for the next iPhone model, but it's possible we'll get some hints come early June when the company hosts its annual Worldwide Developer Conference in San Francisco. New device announcements aren't expected, but Apple executives will take the stage for a keynote event where they'll likely show off new features in iOS 8 and OS X 10.10.