View / Edit Excel 2003 files in Excel 2000
 

I have users who have created a very complex Excel 2003 workbook file with
graphics and formulae. When sent to the customer / client their comment is
that when they open the file in Excel 2000 the data / Graphics are corrupt.
Is there a way to save the file in Excel 2000 format? I wasn't aware there
were file format changes between 2000 and 2003?