PDM 2008 with SW2009 in workstation?

Our PDM server is currently running 2008, and we just got theinstall DVD's for SW2009 this morning.

Can I install '09 on the workstation, and have it cooperate withPDM08? Or do I need to upgrade everything at the same time like theSW07 to SW08 change?SolidworksWorkgroup Pdm