Well that didn't take long. Just hours after Apple released iOS 7.1 to the public, it's been discovered that there are references to two unannounced iPad models hidden inside the update.
A new report from 9to5Mac reveals that iOS 7.1 includes support for "iPad 4,3" and "iPad 4,6," two model numbers that don't belong to any currently-available iPads. For reference, the iPad Air features the model numbers iPad 4,1 and iPad 4,2, while the iPad mini with Retina display is also known by the model numbers iPad 4,4 and iPad 4,5.
So what might these new iPad models be? Unfortunately, the references inside of iOS 7.1 don't offer any clues as to the identities of iPad 4,3 and iPad 4,6. 9to5Mac suggests that they could be minor hardware refreshes or possibly new models intended for an overseas market. That theory makes sense because these new models suggest that one of the devices is a new iPad Air model while the other is an iPad mini with Retina display unit. It's difficult to know what iPad 4,3 and iPad 4,6 are based on the knowledge that we've currently got, though, so for now we'll just have to sit and speculate about what these mysterious iOS devices might be.