VBA compatibility with later versions

I have written a quite a large program in Excel 2003 which is due to be used by my colleagues around the company. Only now am I consdering compatibility issues (a bit late maybe)

I have just tried the program on Excel 2007 and it seems to function OK, the only thing I have noticed different is that screen updating doesn't seem to have been turned off quite the same (Application.ScreenUpdating = False)

Can anyone advise on any compatibility issues i may encounter with either office 2007 or 2010

Thanks