Windows 8.1 release date: download 'BLUE' today, unveiled at Microsoft BUILD developer's conference

Microsoft is expected to release the Windows Blue 8.1 to developers today at the annual BUILD conference which will kick off at 9 a.m. PT in San Francisco.

The version that will be released Wednesday is officially for developers and Microsoft's partners, but anyone will be able to start downloading the free update starting today. The official release date of Windows 8.1 for the public has not yet been announced.

Among the added features of Windows 8.1 will be a start button that will let users automatically shut down from the start screen. The lack of a start button which was so familiar in other Windows versions has been among the complaints received by the tech company.

Apart from the release of the Windows update, fans are hoping that Microsoft will unveil a smaller 7 or 8-inch version of its popular Surface tablet computers.

Microsoft's Vice President Steve Guggenheimer gave a preview of what will happen at the 2013 BUILD Conference on the official Microsoft Blog.

"At Build 2013 this week in San Francisco, we will showcase how developers, app builder and companies of all sizes can create experience on the Windows platform to engage consumers, empower employees, solve problem and drive companies.

"We will talk about how developers of all types will be able to use Microsoft's broad portfolio of product level capabilities spanning our devices and services, and show how these capabilities can be used together to address the needs of today's developers."