I'm not sure how many apps out there are still on Virtual Earth v2, but Microsoft has announced that Virtual Earth v2 will be depricated on March 31st. So, if your app is still on VE v2, you better get working to upgrade it to VE v6 before v2 is turned off. Also, it's worth noting that there are a few breaking differences between v2 and v6, so it may take a little while to upgrade your app.