[WARN ][o.e.d.i.m.MapperService ] [unmapped_type:string] should be replaced with [unmapped_type:keyword]

[dadoonet (David Pilato)]

I checked what Logstash 5.2.2 is sending to elasticsearch and it looks correct to me: https://github.com/logstash-plugins/logstash-output-elasticsearch/blob/5.2.x/lib/logstash/outputs/elasticsearch/elasticsearch-template-es5x.json