Verify that all components meet basic compatibility requirements before upgrading vCenter Server.
Prerequisites
Verify that your system meets the hardware and software requirements. See vCenter Server for Windows Requirements and System Requirements for the New vCenter Server Appliance and Platform Services Controller Appliance
If you have solutions or plug-ins, check the VMware Product Interoperability Matrix. See http://www.vmware.com/resources/compatibility/sim/interop_matrix.php