All vCenter Server Components have to be patched separately. The update process itself if strait forward and can usually been clicked through without answering much questions.
Recommended Upgrade Sequence for VMware vCenter:
- Update vCenter Single Sign On
- Reboot
- Update VMware vCenter Inventory Service
- Update VMware vCenter Server
- Update VMware vSphere Web Client
- Update VMware vSphere Update Manager
- Update ESXi Hosts

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