You have multiple vCenters in different versions and want to upgrade to vCenter 6.0 (U2 or later)? – What is supported and what is unsupported?
There are some possible configurations where you can have different versions of SSO compared to your vCenter versions. This automatically happens during upgrades. There are some combinations that are supported and some combination which are unsupported.
Especially re-installing or re-pointing and “old” vCenter to a newer SSO or PSC version is something which is only supported for vCenters 5.1 pointing to SSO 5.5 – the newer versions can only be installed or repointed to the identical versions.
The following kb contains the table with supported versions of vCenter and SSO/PSC:
Remember when updating your exsiting vSphere 5.5. SSO, you domain name is still “vsphere.local”. Although PSC supports self defined domain names, in an upgrade scenario you will always end with “vsphere.local” as changing the domain name is not supported.
This information can be found in the following kb:
In the above kb you will find a link to the documentation, showing different transitional scenarios and describing the functionality for the various states. See: ”Mixed-Version Transitional Environments in vCenter Server for Windows Upgrades” in the ”vSphere Upgrade Guide“.
Can I mix Windows PSCs with Appliance PSCs? – Yes it is allowed to have Windows PSCs and Appliance PSCs in the same PSC domain – but it is NOT allowed to create HA pairs with different OS PSCs. (also found in the above kb).
By the way if you are dealing with multiple vCenters, there are ways to create command-line installations or upgrades. For details see here:
Scripted way to install/upgrade VC 6.0u2 on Windows: www.vmware.com/…and-upgrade.pdf
Scripted way to deploy/upgrade vCSA 6.0u2: www.vmware.com/…and-upgrade.pdf