By default, Microsoft Office 2007 uses a new file format with the extension “.docx”. If you are trying to share files with users of older versions of Office, this can be a problem. Depending on whether you are the creator or the receiver, there are two ways to solve this problem. To create a more compatible file, users of MS Office 2007 can “Save As” in Office 2003 format. On the receiving side, users of older Office versions can grab a free upgrade from Microsoft that will allow them to read the new format.
Mac and P.C. users that do not own Microsoft Office, or users of earlier versions of Microsoft Office that are not covered by Microsoft compatibility pack, but still want to convert, open and use Word 2007 DOCX or Excel 2007 XLSX files on their own computer, can use “docxconverter 2.0”. See:
http://www.panergy-software.com/products/docxconverter/features.html