Forgot that I Blogged this a while back, but what is cool is that I have just tried to open a docx in Word 2003 and it actually prompts me to download:
[Microsoft Offic Word]
This file was created by a newer version of Microsoft Word. Do you want to download a compatibility pack so that you can work with this file?
[OK] [Cancel]
How does it know? An update must have been applied or it’s in the docx. Anyway it takes you to the download (http://www.microsoft.com/downloads/details.aspx?familyid=941B3470-3AE9-4AEE-8F43-C6BB74CD1466&displaylang=en) page to get the update … that is cool!