Windows 8.1 unveiled: new apps, new features and the return of the Start button:
Windows 8.1 (codenamed "Blue"), the first major update to Windows 8 and RT, was officially announced by Microsoft on May 14, 2013. Following a presentation devoted to the update atBuild Conference 2013, a public beta version of the update was released on June 26, 2013. Windows 8.1 was released to OEM hardware partners on August 27, 2013, and released publicly as a free download through Windows Store on October 18, 2013 at 00:00 NZDT (11:00 UTC, October 17). Unlike past releases and service packs for Windows, volume license customers and subscribers to MSDN Plus and TechNet Plus were initially unable to obtain the RTM version upon its release; a spokesperson stated that the change was to allow Microsoft to work with OEMs "to ensure a quality experience at general availability." However, after criticism, Microsoft reversed its decision and released the RTM build on MSDN and TechNet on September 9, 2013.
The 8.1 update contains a number of improvements throughout the operating system, many of which were intended to address criticism that Windows 8 faced from users and reviewers on launch. Functionality within the "Metro" shell and Windows Store apps is expanded on 8.1 with the ability to snap apps to use half the screen and use up to four apps on a screen at once depending on screen size. Additional customization options (such as expanded color choices, new tile sizes, new backgrounds, the ability to use the desktop wallpaper as its background, and the ability to default to the "All Apps" view) were also added to the Start screen. The PC Settings app was expanded to include access to more options previously exclusive to the desktopControl Panel, and Windows Store apps can now be updated automatically. To improve the usability of the desktop interface, a visible Start button was restored to the taskbar, the desktop can be shown on login instead of the Start screen, and hot corners can now be disabled.
Updates were made to Windows' bundled apps (including Mail, SkyDrive, which now includes a local file manager and deeper OS integration, and Internet Explorer 11), while a number of additional stock apps were added, including Calculator, Sound Recorder, Reading List, Scan, and Help + Tips, which provides an interactive tutorial on how to use Windows. A Bing-based unified search system was also added, including full-screen "hero units" that can surface relevant multimedia content from various sources. Windows 8.1 adds support for a number of new and emerging technologies, such as 3D printing, NFC printing, Miracast media streaming, Wi-Fi Direct printing, and device encryption.
The system requirements for 8.1 remain identical to those of 8, except that x64 variants of Windows 8.1 require CPUs that support four specific x86 instructions: PrefetchW, CMPXCHG16b, LAHF, and SAHF. In addition, Windows 8.1 Preview does not work on some newer Intel Atom-based devices. PrefetchW is currently an AMD exclusive feature, so this requirement applies to AMD CPUs only.
