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As of V3, a new IIS plugin is available which provides a richer and more secure integration with IIS version 7 and later. New Installations should use this version unless they are constrained to use IIS version 6 or earlier, but no such versions of IIS are actually supported and the old module is formally deprecated and likely to be removed in a future major release.
The old ISAPI filter/extension DLL (isapi_shib.dll) is still shipped (though deprecated) and existing installations will be updated to the latest version of the older DLL.
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