Updating Elastic license

Hi, I got a licence key (alphanumeric sequence), but checking the documentation it requires a json file to update the license, I was wandering if you can update the license with this key that I got....or do I need some other data like the one displayed in the documentation.

https://www.elastic.co/guide/en/elasticsearch/reference/current/update-license.html

PUT _license?acknowledge=true
{
  "licenses": [
    {
      "uid":"893361dc-9749-4997-93cb-802e3d7fa4xx",
      "type":"basic",
      "issue_date_in_millis":1411948800000,
      "expiry_date_in_millis":1914278399999,
      "max_nodes":1,
      "issued_to":"issuedTo",
      "issuer":"issuer",
      "signature":"xx"
    }
    ]
}

How did you get the license key? All licenses I have downloaded from elastic.co have been in the form of JSON documents. Which version are you using?