The Versioning feature isn't available in Microsoft Office Word 2007. If you save a document that contains versioning in the Microsoft Office Word 97-2003 file format and then open it in Office Word 2007, you will lose access to the versions.
Important: If you open the document in Office Word 2007 and you save the document in either Word 97-2003 or Office Word 2007 file formats, you will permanently lose all versions.
Use the Version Extraction Tool
You can save versions of a document as multiple files by using the Version Extraction Tool (VET), which is included in the Office Migration Planning Manager (OMPM). The OMPM and the VET are available on the Microsoft TechNet Web site.