Remove support for Elasticsearch 5 and 6 ?

[Etienne Chauchot]

Hi all,

Elastic no more supports Elastic 5 and 6 (1). We are in the middle of 
removing long overdue Elasticsearch 2 support but maybe it is time to 
remove support for ES5 and ES6 from Beam as well.

WDYT ?

[1] https://endoflife.date/elasticsearch


Best

Etienne