Windows 8.1 is an operating system that was produced by Microsoft and released as part of the Windows NT family of operating systems. It was released to manufacturing on August 27, 2013, and broadly released for retail sale on October 17, 2013, about a year after the retail release of its predecessor. It was Microsoft's operating system for use on personal computers, including home and business desktops, laptops, tablet PCs and media center PCs until it was succeeded by Windows 10 on July 29, 2015. Windows 8.1 was made available for download via MSDN and Technet and available as a free upgrade for retail copies of Windows 8 and Windows RT users via the Windows Store. A server counterpart was released on October 18, 2013, entitled Windows Server 2012 R2. Microsoft ended mainstream support for Windows 8.1 on January 9, 2018, and extended support will end on January 10, 2023.

Windows 8.1 aimed to address complaints of Windows 8 users and reviewers on launch. Visible enhancements include an improved Start screen, additional snap views, additional bundled apps, tighter OneDrive (formerly SkyDrive) integration, Internet Explorer 11 (IE11), a Bing-powered unified search system, restoration of a visible Start button on the taskbar, and the ability to restore the previous behavior of opening the user's desktop on login instead of the Start screen. Windows 8.1 also added support for such emerging technologies as high-resolution displays, 3D printing, Wi-Fi Direct, and Miracast streaming, as well as the ReFS file system.^[6] After January 12, 2016, Microsoft announced that Windows 8 users would need to upgrade to Windows 8.1 or Windows 10 for continued support.

Windows 8.1 received more positive reception than Windows 8, with critics praising the expanded functionality available to apps in comparison to Windows 8, its OneDrive integration, its user interface tweaks, and the addition of expanded tutorials for operating the Windows 8 interface. Despite these improvements, Windows 8.1 was still criticized for not addressing all issues of Windows 8 (such as poor integration between Metro-style apps and the desktop interface), and the potential privacy implications of the expanded use of online services. As of October 2020, 4.16% of traditional PCs running Windows were running Windows 8.1

History

 report detailed that Microsoft was planning to shift to a more "continuous" development model, which would see major revisions to its main software platforms released on a consistent yearly cycle to keep up with market demands. Lending credibility to the reports, Foley noted that a Microsoft staff member had listed experience with "Windows Blue" on his LinkedIn profile, and listed it as a separate operating system from 8.^[8][9]

A post-RTM build of Windows 8, build 9364, was leaked in March 2013. The build, which was believed to be of "Windows Blue", revealed a number of enhancements across Windows 8's interface, including additional size options for tiles, expanded color options on the Start screen, the expansion of PC Settings to include more options that were previously exclusive to the desktop Control Panel, the ability for apps to snap to half of the screen, the ability to take screenshots from the Share charm, additional stock apps, increased SkyDrive integration (such as automatic device backups) and Internet Explorer 11.^[10][11] Shortly afterward on March 26, 2013, corporate vice president of corporate communications Frank X. Shaw officially acknowledged the "Blue" project, stating that continuous development would be "the new normal" at Microsoft, and that "our product groups are also taking a unified planning approach so people get what they want—all of their devices, apps and services working together wherever they are and for whatever they are doing