Assuming the Elasticsearch version was updated from version 2 to version 5 as part of a patch day.

If necessary, check again which Elasticsearch version is installed:

$ pkg info | grep elasticsearch
elasticsearch2-2.4.6         Full-text search engine for Java

Archiving the current configuration:

$ sudo mv /usr/local/etc/elasticsearch /usr/local/etc/elasticsearch2

Link the new configuration provided:

$ sudo ln -s elasticsearch5 /usr/local/etc/elasticsearch

Restart Elasticsearch:

$ sudo service elasticsearch restart