Login to vCenter MOB page using the credentials
https://<VC FQDN or IP>/mob >> content >> About (to get the details of VC)
Now you can validate the vCenter ID here
Also, to check on the API difference, you need to look into the API reference guides/ release notes (like Known Issues, Resolved Issues) or you can open up an SR with API/SDK support team to get more details.
Hope this helps you.
Thanks for the response,I was able to find the vcenter id.
I will see if I can check if I can open an SR with the API team to see what is expected for the context_id.