The first version of iOS 7 is yet to be released to end-users, but Apple seems to be in the process of testing iterative updates to the latest version of its operating system already.
The web analytics for popular Apple-centric site 9to5Mac show devices with iOS versions 7.0.1, 7.0.2, and 7.1 having visited the website recently, from locations in and around Cupertino, where Apple has its headquarters. Moreover, all the visits seem to be from iPads, which lends credence to an earlier rumor that the upcoming iPads will run a successive update to iOS 7.0 (likely 7.1), which will later be rolled out to both new and old iPhones.
As is usually the norm, both iOS 7.0.1 and 7.0.2 should be minor updates that roll out soon after iOS 7.0, in order to fix bugs and improve stability (and perhaps battery life, which often becomes an issue for users after a major iOS update). iOS 7.1 should follow a few weeks or months later and bring along new features, once the iPad 5 and iPad mini 2 are launched.