> I think what they're saying is that you have to "save as" in order to be allowed to edit. The issue is that roundtripping between Office 2007+ and Office 20

> I think what they're saying is that you have to "save as" in order to be allowed to edit. The issue is that roundtripping between Office 2007+ and Office 2003 is unreliable and will often result in corrupted files. Using Office 2003 (with Compatibility Pack add-on to open xlsx and docx) is ok for isolated work but can be unreliable for collaborative back & forth editing depending on what features are used. E.g. cell colors used in Excel 2007 xlsx get corrupted in Excel 2003 xls.