MacWord 98/01/v.X/04 and WinWord 97/00/02/03 all share the same file
format (features vary, of course).
There may be some differences if the files contain macros. All Mac
versions and Word 97 use VBA 5, while the other WinWord versions use VBA
6, so any VBA6 functions won't compile in the VBA 5 versions.