Upgrade to ES HighLevelClient
- more functionality available since 6.3
- quite a lot of features still missing in 6.3 (get mapping, index stats…)
(from redmine: issue id 1105, created on 2018-08-01tgradl, closed on 2019-05-14)
(from redmine: issue id 1105, created on 2018-08-01tgradl, closed on 2019-05-14)