There are FOUR main versions of Windows 8:
- Windows 8 - This is the basic version that is available in both IA-32 and x64 architectures. You can install this version on any standard computer such as an Intel-based computer.
- Windows 8 Pro - This version is targeted toward enthusiasts and business users who require features such as domain join, incoming Remote Desktop connections, EFS, VHD booting, Group Policy. BitLocker and BitLocker To Go are also available. Windows Media Center is also available for this version. As this version is the "core" version it can be upgraded to 8.1 which means that Windows 8 Pro and Windows 8 Enterprise can also be upgraded to 8.1 (i.e. they become 8.1 Pro and 8.1 Enterprise).
- Windows 8 Enterprise - This version provides all the features of Windows 8 pro plus additional business-oriented features. This version is only available through enterprise-class channels - i.e. cannot be bought off-the-shelf, such as the retail versions (Windows 8 and Windows 8 Pro).
- Windows RT - This version is unique in that it was designed to utilise the ARMv7 architecture that is present in many mobile devices such as the Surface RT that use ARM-based processors. Windows RT is not available for IA-32 and x64 processors because it is an unnecessary requirement when one can use Windows 8, Windows 8 Pro or Windows 8 Enterprise. Windows RT cannot be upgraded to higher versions such as Pro or Enterprise.
The upgrade process is the same as Windows 7 where a user can "anytime upgrade" a compatible version by entering a valid product key for the new version. This will then prompt the download of the required additional features. If you prefer, however, a "Pro pack" is available that allows an offline upgrade.