Elasticsearch is a required database component for ALM Octane.
Elasticsearch version 5.x is required for ALM Octane versions 12.55.25 up to and including 12.60.35.
Elasticsearch version 6.x is required for ALM Octane 12.60.47 and later.
This article provides the steps for upgrading the Elasticsearch database from version 2.x to 5.x and from version 5.x to 6.x.
Upgrading from Elasticsearch 2.x to 5.x instructions:
Upgrading from Elasticsearch 5.x to 6.x instructions:
Upgrading from Elasticsearch 5.x to 6.x instructions - Linux