Hello, I agree with the reply above, that SSO installs fresh copy. Try to use this links https://www.vmware.com/support/vsphere5/doc/vsphere-esx-vcenter-server-55-release-notes.htmlhttp://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2060511 Hope will help.
Your Oscar