Microsoft has been in a state of “shut up and ship” with Windows Phone for more than a year now. While the company has released a few minor updates to Windows Phone 8, its feature set hasn’t changed significantly from when Microsoft first introduced the mobile OS in October 2012. The software giant refuses to discuss or acknowledge an upcoming update, Windows Phone 8.1, but a recent software development kit leak has highlighted the huge number of feature changes that will arrive in the coming months and put Windows Phone more on par with iOS and Android. One of the main feature additions is Cortana, a personal digital assistant named after Microsoft’s Halo game series. Cortana first emerged after a Microsoft employee lost a phone running Windows Phone 8.1 last year. Sources familiar with Microsoft’s Windows Phone work have revealed to The Verge that Cortana will replace the built-in Bing search feature, which is currently launched through a dedicated hardware key, and acts as a digital assistant with a mix of Siri and Google Now functionality.