[Feature] XPS Viewer [Differences from 3.5 SP1] WPF does not include the Microsoft XML Paper Specification Essentials Pack (XPSEP). XPSEP is included with Windows 7 and Windows Vista. On a computer that is running Windows XP without the .NET Framework 3.5 SP1 installed, printing by using a WPF API other than those in PrintDialog will rely on the WINSPOOL. Some printer capabilities will not be reported and some printer settings will not be applied during printing. [Recommended changes] 
If needed, install the Microsoft XML Paper Specification Essentials Pack.