Windows Server 2008 R2 Upgrade Paths

From Windows Server 2008 (RTM, SP2)	Upgrade to Windows Server 2008 R2
Datacenter	Datacenter
Datacenter Core	Datacenter Core
Enterprise	Enterprise, Datacenter
Enterprise Core	Enterprise Core, Datacenter Core
Foundation (SP2 only)	Standard
Standard	Standard, Enterprise
Standard Core	Standard Core, Enterprise Core
Web	Standard, Web
Web Core	Standard Core, Web Core

From Windows Server 2008 (RC, IDS, RTM)	Upgrade to Windows Server 2008 R2
Datacenter	Datacenter
Datacenter Core	Datacenter Core
Enterprise	Enterprise, Datacenter
Enterprise Core	Enterprise Core, Datacenter Core
Foundation	Standard, Foundation
Standard	Standard, Enterprise
Standard Core	Standard Core, Enterprise Core
Web	Standard, Web
Web Core	Standard Core, Web Core

Upgrades to Windows Server 2008 R2 from the following operating systems are not supported:
- Windows 95, Windows 98, Windows Millennium Edition, Windows XP, Windows Vista, Windows Vista Starter, or Windows 7
- Windows NT Server 4.0, Windows 2000 Server, Windows Server 2003 RTM, Windows Server 2003 with SP1, Windows Server 2003 Web, Windows Server 2008 R2 M3, or Windows Server 2008 R2 Beta
- Windows Server 2003 for Itanium-based Systems, Windows Server 2008 for Itanium-based Systems, Windows Server 2008 R2 for Itanium-based Systems
Cross-architecture in-place upgrades (for example, x86 to x64) are not supported.
Cross-language in-place upgrades (for example, en-us to de-de) are not supported.
Cross-edition upgrades (for example, the Windows Server 2008 Foundation SKU to the Windows Server 2008 Datacenter SKU) are not supported.
Cross-build type in-place upgrades (for example, fre to chk) are not supported.

Windows Server 2008 R2 Beta to Windows Server 2008 R2 RC In-Place Upgrade is supported.

Windows Server 2008 R2 Beta to Windows Server 2008 R2 RTM In-Place Upgrade is not supported.

Windows Server 2008 R2 RC to Windows Server 2008 R2 RTM In-Place Upgrade is supported.

Evaluate Windows Server 2008 R2