The version of OpenSearch supported for the Sentinel version 8.6.0 is 1.3.9. To upgrade Sentinel from version 8.5.1.1 or below, which is running with a cluster of external Elasticsearch nodes, to Sentinel 8.6.0, you need to delete the data and configurations on each external node. Afterward, uninstall Elasticsearch and install the supported version of Opensearch (1.3.9) on the nodes. For more information, see Installing OpenSearch. Ensure that the OpenSearch.yml files are updated with the node information.
If you wish to save any custom dashboards and visualizations that you might have created in Kibana on or before Sentinel 8.5.1.1, export them from Kibana and then import them back to Opensearch Dashboards after the upgrade.
NOTE:After upgrading to 8.6.0, the new OpenSearch will not have any older data. If you want to forward the older data to OpenSearch you can do it using the data uploader tool. It can be done after the connection between all the nodes is made and both OpenSearch and Opensearch Dashboards are running. For more information, see the Section 36.0, Migrating Data.