Appendix G: Detect the Version of WSUS
The way you detect the version of a WSUS installation has changed in WSUS 3.0 SP2. In previous versions, WSUS used Microsoft© Windows© Installer product keys. In WSUS 3.0 SP2, versioning is persisted in the registry to support new installer technologies such as CBS for Windows Vista® and Windows Server® 2008.
Versioning in WSUS 2.0
Check for the install state of the following Windows Installer product key:
In WSUS 2.0, the WSUS registry key:
has an InstallType subkey with the following possible values:
Frontend = 32
Backend = 64
FullInstall = 128
You can upgrade from WSUS 2.0 to WSUS 3.0 SP2 for installations with the Frontend and FullInstall values. For the Backend value, you would uninstall WSUS, leaving the database behind. This database will be upgraded when the front-end WSUS server that points to the database is upgraded.
WSUS 3.0 SP2 pre-release candidate versions
Versions of WSUS 3.0 SP2 that precede the first release candidate version also have Windows Installer product keys. There is one product key for 32-bit architectures and another for 64-bit architectures.
WSUS 3.0 SP2 Release Candidate 1 and later versions
For WSUS 3.0 SP2, there is no Windows Installer product key, but there are two registry values: InstallType supports only two installation types: 1 = install or 2 = console-only install. VersionString is a string of the form Major.Minor.Build.Revision.
To detect WSUS versions
Check that SUS 1.0 and WSUS 2.0 are not installed (by looking for the product keys).
Find the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Update Services\Server\Setup.
Check the InstallType values (32/64/128 if WSUS 2.0, 1/2 if WSUS 3.0).
Check for VersionString values.