From Grigori's blog post:
New In This Release
The February 2008 Release of the Guidance Automation Extensions and Guidance Automation Toolkit has the following improvements to the earlier release, the July 2007 Community Technology Preview:
− Support for Visual Studio 2005 and/or Visual Studio 2008. This version of GAX will run on either version of Visual Studio. If you don’t have GAX installed, you can install GAX to support Visual Studio 2005 or Visual Studio 2008 or both. The installer will automatically determine which versions of Visual Studio you have installed.
− Updating GAX.
§ If you have a previous version of GAX installed on Visual Studio 2005, it will be updated to the February 2008 release of GAX. You are no longer required to uninstall GAX and the corresponding guidance packages.
§ Guidance packages that are registered with the previous version of GAX will automatically be registered with the current version of GAX (GAT, however, will require an update – see the information below).
− Visual Studio side-by-side support. If you have Visual Studio 2005 and Visual Studio 2008 running side-by-side, you can have GAX running against both versions. Guidance packages developed and registered through GAT for a specific version of Visual Studio (2005 or 2008) will only be available in that version. Guidance packages designed for Visual Studio 2005 and installed through an MSI will only be available in Visual Studio 2005. Installation of any guidance package through an MSI that does not explicitly prompt for the version of Visual Studio to install to, will install to Visual Studio 2005 by default.
− Improved Uninstaller. During GAX uninstallation, you can click the Check Installed Packages button for the list of all registered guidance packages. If you proceed with GAX removal, the uninstaller will only attempt to automatically uninstall those guidance packages that were registered manually using GAT. If you have guidance packages that were installed through an MSI(s), you should not proceed with removing GAX. Instead, you should use the Add or Remove Programs tool to uninstall these guidance packages.
In addition, this release of GAX has the following fixes:
− A blank error message was displayed if you attempted to uninstall GAX before uninstalling GAT or other registered packages when running Windows Vista.
− A FileLoadException error was displayed if you used the Guidance Package Manager on Visual Studio 2008 Professional.
− GAX and GAT would not properly validate and recognize custom Visual Studio project types when unfolding templates for custom project types registered only in the experimental hive.
GAX and GAT must be downloaded and installed separately. GAT requires that GAX is installed first.
If you have a previous version of GAX installed on Visual Studio 2005, it will be updated to the February 2008 release of GAX. You are no longer required to uninstall GAX and the corresponding guidance packages (with an exception of GAT, which must be re-installed).