Microsoft showcases the latest version of Windows.

At Build 2014, an event for software developers and programmers held in San Francisco, Microsoft unveiled new advanced features for Windows, including Windows Phone 8.1, a new update to Windows 8.1, and a comprehensive platform for application development. Simultaneously, they announced a $0 licensing program for OEM and ODM partners to develop Windows smartphones and tablets under 9 inches.

Microsoft detailed new development opportunities on the Windows platform—a platform that's popular across all devices—with a single set of tools and a shared infrastructure across both Windows and Windows Phone Stores, coupled with a clear commitment to interoperability. By maximizing opportunities across the widest range of devices and services, Microsoft further emphasized its ongoing commitment to supporting partners and the solution development community.

Also at the event, Nokia launched three new Lumia Windows Phone 8.1 smartphones: the Lumia 930, Lumia 635, and the first dual-SIM phone - the Lumia 630.

Windows Phone 8.1 will replace Windows Phone 8 in the coming months. This version will also begin pre-installed on new phones this month. Cortana will launch soon in the US as a beta, in the UK and China in the second half of 2014, and in other countries in 2015. Registered developers can update their phones to Windows Phone 8.1 this month.

According to Hanoi Moi