Prevent saving in Excel 2007
 

I have a spreadsheet with macros that is used by a number of people with
different versions of Excel. So far it works fine if I manually ensure that
all versions for the people working with Excel 2007 save in 1997-2003
compatability mode. Is there a way to prevent the Excel 2007 users from
saving the files in Excel 2007 or automatically saving the files in 1997-2003
compatability mode?

Thanks in advance.