Outlook 2003

Something else to consider is Outlook (Office) 2003 is one year from end-of-life. After that, the software may work but issues will not be addressed by Microsoft and, more importantly, any vendors software, like X1, are not likely to test their application with it. Testing is expensive and is typically prioritized to the most common products first to be get best-bang-for-buck and out-of-life products last.

See:
Microsoft Support Lifecycle for Office 2003
Microsoft Support Lifecycle Policy FAQ

Microsoft supports products for about, and at least, ten years.

---