This is a very useful feature with vSphere 7.Earlier version when we need to do modification or apply OS patches to template we need to convert template back to vm and had do that, but with vCenter 7 , we can maintain versioning.
How to do that?
1. First thing these templates should be in content library
2. I have created my template and its in my content library. If I click on template , we can see the version tab
3. Now I’m going to install Windows patches on this template, therefore I select the template and click on Check out VM From This Template on versioning tab. Then I have to give temporary name for this vm
4. We can just follow the next steps and click on Power on VM after check out and click on Finish
5. Now we can do all the changes according to our requirement. Then shut down the vm
6. Click on the template and now we can check in the vm to template
8. Now we have multiple versions of the VM template, when we deploy the vm we can select the vm according to our requirement