Elastisearch not updated

(from github.com/luigigf49)
Hi Marevol,
I should interface a version of elasticsearch 5.x that I can’t update otherwise I would have to upgrade the PHP application that uses this database.
Which version of Fess is compatible with Elasticsearch 5.x?

Thanks
Luigi

(from github.com/marevol)
elasticsearch 5.x is EOLed.
For supported versions, see Download page.