Windows 8
Windows 8 (also sometimes referred to as
Windows 8 (Core) to distinguish from the OS itself) is the basic edition of Windows for the IA-32 and x64 architectures. This edition contains features aimed at the home market segment and provides all of the basic new Windows 8 features.
Windows 8 Pro
Windows 8 Pro is comparable to Windows 7 Professional and Ultimate and is targeted towards enthusiasts and business users; it includes all the features of Windows 8. Additional features include the ability to receive Remote Desktop connections, the ability to participate in a Windows Server domain, Encrypting File System, Hyper-V, and Virtual Hard Disk Booting, Group Policy as well as BitLocker and BitLocker To Go. Windows Media Center functionality is available only for Windows 8 Pro as a separate software package.
Windows 8 Enterprise
Windows 8 Enterprise provides all the features in Windows 8 Pro (except the ability to install the Windows Media Center add-on), with additional features to assist with IT organization (see table below). This edition is available to Software Assurance customers, as well as MSDN and Technet Professional subscribers, and was released on 16 August 2012.
Windows RT
Windows RT is only available pre-installed on ARM-based devices such as tablet PCs. It includes touch-optimized desktop versions of the basic set of Office 2013 applications to users—Microsoft Word, Excel, PowerPoint, and OneNote, and supports device encryption capabilities. Several business-focused features such as Group Policy and domain support are not included.
Software for Windows RT can be either downloaded from Windows Store or sideloaded, although sideloading on Windows RT must first be enabled by purchasing additional licenses through Microsoft volume licensing outlet. Desktop software that run on previous versions of Windows cannot be run on Windows RT as Windows Store apps are based on Windows Runtime API which differs from the traditional apps. According to CNET, these essential differences may raise the question of whether Windows RT is an edition of Windows: In a conversation with Mozilla, Microsoft deputy general counsel David Heiner was reported to have said Windows RT "isn't Windows anymore." Mozilla general counsel, however, dismissed the assertion on the basis that Windows RT has the same user interface, application programming interface and update mechanism.
Unlike Windows Vista and Windows 7, there are no Starter, Home Basic, Home Premium, or Ultimate editions.
Regional restrictions and variations
All mentioned editions have the ability to use language packs, enabling multiple user interface languages. (This functionality was previously only available in Windows 7 Ultimate or Enterprise.) However, in China and other emerging markets, a variation of Windows 8 without this capability, called Windows 8 Single Language, is sold. This edition can be upgraded to Windows 8 Pro.
Additional Windows 8 editions specially destined for European markets have the letter "N" (e.g. Windows 8.1 Enterprise N) suffixed to their names and do not include a bundled copy of Windows Media Player. Microsoft was required to create the "N" editions of Windows after the European Commission ruled in 2004 that it needed to provide a copy of Windows without Windows Media Player tied in.
Windows 8.1 with Bing is a reduced-cost SKU of Windows 8.1 for OEMs that was introduced in May 2014. It was introduced as part of an effort to encourage the production of low-cost devices, whilst "driving end-user usage of Microsoft Services such as Bing and OneDrive". It is subsidized by Microsoft's Bing search engine, which is set as the default within Internet Explorer, and cannot be changed to a third-party alternative by the OEM. This restriction does not apply to end-users, who can still change the default search engine freely after installation. It is otherwise identical to the base edition.
The following in-place upgrade paths are supported from Windows 7. Note that it is only possible to upgrade from an IA-32 version of Windows 7 to an IA-32 version of Windows 8; an x64 version of Windows 7 can only be upgraded to an x64 version of Windows 8. It is possible to upgrade Windows XP SP3 or Windows Vista to Windows 8 Pro. The retail package entitled Windows 8 Pro Upgrade was restricted to upgrading a computer with licensed Windows XP SP3, Windows Vista or Windows 7. Finally, there is no upgrade path for Windows RT, as it is the only version of Windows that currently supports the ARM architecture.
