Double Fixing

Now that Windows 7 is starting to see a lot of usage, I've had a few questions about installing hotfixes from product support for WCF issues when dealing with both Windows Vista/Server 2008 and Windows 7/Server 2008R2 systems.

The two platforms are not quite the same when it comes to WCF (and other .Net products). Windows 7 comes with .Net 3.5.1, which is basically something like .Net 3.5 service pack 1 plus a few additional changes that were intended for broad release. These changes include a subset of the hotfixes that had been released prior to Windows 7 (primarily ones that were low risk to release broadly and would be beneficial to multiple customers).

In some cases this means that you don't even need to apply a hotfix on Windows 7 because the fix was already included. However, if there was a hotfix for Windows Vista, and the fix was not part of Windows 7, then you can't just install the hotfix on Windows 7 because the base versions are different. Instead, you need to request a new fix specifically for Windows 7 if we haven't made one available yet.