Apple reportedly has been working on a redesign of its e-book app for iPhones and iPads, in what could be the biggest upgrade to its e-book service in years. The new app reportedly is undergoing testing and will be released in the next few months. It will have a simpler interface that better highlights books currently being read in a section called "Reading Now," and a redesigned digital bookstore that has a dedicated tab for audio books and looks more like the App Store redesign introduced last year.