The new version of the mobile OS was spotted in a tool-tip message in the updated Windows Phone 8.1 SDK files. The update hints at a secondary live tile that might be removed, and the API might be re-designed for some other new features. According to rumors, Microsoft is also planning to change the start screen in Windows Phone 8.5.

The Windows Phone 8.1 update will allow developers to choose a shorter update/refresh period for live tiles. Currently, the update occurs every 30 minutes, but with the Windows Phone 8.1, update will happen after every minute. Developers will be able to manage notifications by tagging, grouping or replacing them as the new one comes in. They can also see notifications in the Action center and even set a 'Ghost toast'.

Microsoft is planning to launch the Windows Phone 8.1 update in April at the Build developer conference. The update will also bring Microsoft's much anticipated Siri-like voice assistant, called Cortana.