According to reports, the update will be making a number of changes and will be bringing numerous bug fixes to the operating system, as well as updating some of the visuals of the operating system, changing some color schemes and design in the process. There will also be new options added, such as the ability to directly disable the parallax effect when choosing a new wallpaper, which reportedly causes motion sickness for some users. Prior to this, the settings to disable the effect was found quite hidden in the settings which was not as accessible. There will also be new animations added to the operating system as some of the many changes that Apple will be making.
While we have no idea when Apple will release iOS 7.1, some have speculated that it might only be in March that we might see the update, putting it somewhat close to WWDC 2014 which is usually when Apple announces their next major update, which we can only assume is iOS 8.