Microsoft has released MSXML 4 SP 1 (Microsoft XML Core Services)

MSXML 4.0 SP1 offers a number of new features and improvements over the MSXML 3.0, including support for the XML Schema language and substantially faster parser and XSLT engine. MSXML 4.0 SP1 is a complete replacement for MSXML 4.0 RTM and provides a number of bug fixes. It can not replace MSXML 3.0, because some obsolete and non-conformant features are no longer supported. MSXML 4.0 installs side by side with MSXML 3.0 and earlier, without any interference.

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