Windows 8.1 is a personal computer 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 reached general availability on October 17, 2013, about a year after the retail release of its predecessor. Windows 8.1 was made available as a free upgrade for retail copies of Windows 8 and Windows RT users via the Windows Store. Microsoft ended mainstream support for Windows 8.1 on January 9, 2018, but extended support will not end until 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, 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. 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, along with its user interface tweaks and the addition of expanded tutorials for operating the Windows 8 interface. Despite these improvements, Windows 8.1 was still criticised for not addressing all digressions of Windows 8 (such as a poor level of integration between Metro-style apps and the desktop interface), and the potential privacy implications of the expanded use of online services. As of November 2019[update], 5.07% of traditional PCs running Windows are running Windows 8.1.