When you attempt to install the license as it is written here https://www.elastic.co/guide/en/x-pack/5.1/installing-license.html
curl -XGET -u elastic 'http://x.x.x.x:9200/_xpack/license?acknowledge=true' -d @license.json
Enter host password for user 'elastic':
{"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"request [/_xpack/license] contains unrecognized parameter: [acknowledge]"}],"type":"illegal_argument_exception","reason":"request [/_xpack/license] contains unrecognized parameter: [acknowledge]"},"status":400}
Server one cluster configuration is made