Microsoft has announced, via a post on the official Windows blog by Brandon LeBlanc, that four editions of Windows 8 will launch, but that only two will be readily available. The post also confirmed that ‘Windows 8’ will be the official title of the operating system when it launches.
The four editions are: Windows 8, Windows 8 Pro, and Windows RT, with an Enterprise edition being available as well. Windows 9 and the Pro variant are nearly identical, with the Pro version carrying extra features “for encryption, virtualization, PC management and domain connectivity.” Windows RT (Runtime) is aimed at devices powered by ARM processors and will only be available pre-installed on those PCs and tablets. Windows 8 Enterprise will only be available for Microsoft customers with Software Assurance agreements and will be identical to Windows 8 Pro, with a few added features.
The announcement post provides a tabled list of the features available in the various editions. This has been reproduced below. Nothing regarding pricing or availability has been revealed yet.
| Feature name | Windows 8 | Windows 8 Pro | Windows RT |
| Upgrades from Windows 7 Starter, Home Basic, Home Premium |
x |
x |
|
| Upgrades from Windows 7 Professional, Ultimate | x | ||
| Start screen, Semantic Zoom, Live Tiles | x | x | x |
| Windows Store | x | x | x |
| Apps (Mail, Calendar, People, Messaging, Photos, SkyDrive, Reader, Music, Video) | x | x | x |
| Microsoft Office (Word, Excel, PowerPoint, OneNote) | x | ||
| Internet Explorer 10 | x | x | x |
| Device encryption | x | ||
| Connected standby | x | x | x |
| Microsoft account | x | x | x |
| Desktop | x | x | x |
| Installation of x86/64 and desktop software | x | x | |
| Updated Windows Explorer | x | x | x |
| Windows Defender | x | x | x |
| SmartScreen | x | x | x |
| Windows Update | x | x | x |
| Enhanced Task Manager | x | x | x |
| Switch languages on the fly (Language Packs) | x | x | x |
| Better multiple monitor support | x | x | x |
| Storage Spaces | x | x | |
| Windows Media Player | x | x | |
| Exchange ActiveSync | x | x | x |
| File history | x | x | x |
| ISO / VHD mount | x | x | x |
| Mobile broadband features | x | x | x |
| Picture password | x | x | x |
| Play To | x | x | x |
| Remote Desktop (client) | x | x | x |
| Reset and refresh your PC | x | x | x |
| Snap | x | x | x |
| Touch and Thumb keyboard | x | x | x |
| Trusted boot | x | x | x |
| VPN client | x | x | x |
| BitLocker and BitLocker To Go | x | ||
| Boot from VHD | x | ||
| Client Hyper-V | x | ||
| Domain Join | x | ||
| Encrypting File System | x | ||
| Group Policy | x | ||
| Remote Desktop (host) | x |
Source: Windows Blog