After upgrading a vCenter 9.x that is integrated with VCF Operations 9.x you notice the client plugin in the vCenter for VCF Operations does not get upgraded to the new version.
VCF Operations 9.x
The client plugin will not be upgraded when VCF Operations or vCenter 9.x are upgraded, this is by design.
The client plugin will only be updated when the VCF Operations SSL certificate is renewed.