Microsoft has published a new beta of its Open XML File Format Converter for Mac.

The new version of the software appeared earlier this week. It's required equipment for Mac users seeking to convert documents created in Microsoft's proprietary Open XML standard (which has so far failed to be ratified as a full-fledged industry standard) into a format that's compatible with Office 2004 and Office v.X for Mac.

The software is capable of both individual and batch file conversions of the following Open XML formats: Word Document (*.docx); Word Macro-Enabled Document (*.docm); PowerPoint Presentation (*.pptx); PowerPoint Show (*.ppsx); PowerPoint Template (*.potx).

Microsoft warns that this version of the converter is not compatible with Microsoft Office 2008 for Mac. "If Office 2008 is installed on your computer, do not install this version of the converter as it might cause problems with Office 2008 applications," the company says.

The converter is a Beta release, and might be unable to convert all the data in Open XML files.