Ciao
From
https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/products/vsphere/vmware-vsphere-pricing-whitepaper.pdf
vCenter Server is available in the following packages:
• vCenter Server for Essentials – Integrated management for vSphere Essentials Kits.
• vCenterServer Foundation –Powerful management tool for smaller environments
looking to rapidly provision, monitor and controlVMs.
• vCenter Server Standard – Highly scalable management with rapid provisioning,
monitoring, orchestration and control of all VMs in a vSphere environment. vCenter
ServerHighAvailabilitydoesnotrequire a separate vCenterServerStandard license
for the passive or witness node.
then you have two possibilities:
- buy the vCenter Server Foundation license and keep the standard ESXi licenses you have
- check the possibility of transforming ESXi Standard licenses into vSphere Essential Plus (where you have included the vCenter Server for Essentials)
For the patch or major upgrade:
When you purchase your license, you are entitled to all minor upgrades for the life of the product. So if you purchase vSphere 6.x licensing and let your subscription expire, you will still be able to download all 6.x patches and upgrades.. so 6.0, 6.5, and 6.7 would have been covered by your 6.x licensing with all patches in between. You would NOT be able to download 7.x software though without current support.
If you let the support expire when you go to renew you may be asked for an extra 20%.
However, I recommend that you speak directly to a VMware sales representative or a sales representative from a partner company