Windows Phone is a mobile operating system developed by Microsoft for smartphones. It is the successor to Windows Mobile, although it is incompatible with the earlier platform. With Windows Phone, Microsoft created a new user interface, featuring a design language named "Modern". Unlike its predecessor, it is primarily aimed at the consumer market rather than the enterprise market. It was first launched in October 2010 with Windows Phone 7. Windows Phone 8.1, which was released in final form to developers on April 14, 2014 and will be pushed out to all phones running Windows Phone 8 over the coming months, is the latest release of the operating system.