I am in a similar situation where I have a ESXi 4.1 free version running for > 60 days and it has a license key.
Now I want to upgrade to the Essestial Kit, but am unsure if I will be FORCED to upgrade to 5.1 ?
I have read another post where it looks like I cannot add a license to a 4.1 Host if its been running with a free license and that the essesntial license
is not accepted.
So will I be forced to upgrade to 5.x ?
The post which talks about this issue is :-
http://communities.vmware.com/message/2164800
All I want to do is be able to have an external application (IBM Cloud management) use the management APIs to create VMs. I understand that this
feature is NOT avaliable in the free ESXi versions (read only).