Guys, just be very careful about upgrading your office pack.
Came across a system some years back – front end-end Excel, back end SAS. The company did a staged upgrade across their 3000 users, from Office 95 to Office 97. Although the front part of package looked much the same, they changed all the OLE commands at the back end. The guys re-write the system from scratch, and ask a very embarrassing question when the users logged in: Which version of Office do you have?
Do some investigation about what is changing in the background of the Office pack, and ensure that it does not impact on your Client / server applications.