When working with a client that is still using Exchange 2003, we noticed a problem when trying to install Microsoft Office 2013. Namely, Outlook 2013 doesn’t support Exchange 2003.
We went to Microsoft for an explanation to this issue. They explained that the new features in Outlook 2013 are not compatible with the architecture of Exchange 2003 so much so that it causes the 2 versions to be incompatible.
Interestingly enough, this is an ongoing issue for the Outlook and Exchange relationship. When Outlook 2010 was released, it was not compatible with Exchange 2000. Also, Outlook 2007 doesn’t play nice with Exchange 5.5. So the same holds true for the newest release of Outlook and the Exchange that is two versions behind.
We highly reccomend anyone looking at upgrading systems to use Outlook 2013, also take a look at thier exchange environments to make sure they are upgraded as well to prevent this conflict.