Word, Excel and Powerpoint were forwards and backwards compatible from 1997 to 2004. The newer versions emitted various backward compatible formatting (eg Word

Word, Excel and Powerpoint were forwards and backwards compatible from 1997 to 2004. The newer versions emitted various backward compatible formatting (eg Word 2000 supported table-in-table, but emitted sufficient formatting for Word 97 to at least see one level of tables and consider the rest of the cells to be paragraphs) It was far from bug-free though.