full cluster backup/snapshot of the source cluster, and ideally to perform the migration on a restore of the source cluster. For more information on ElasticSearch 5 snapshots and restore you can find

PERFORM THE MIGRATION CHECKLIST Before starting the migration, please ensure that: You do have a backup of your data You did practice the migration in a staging environment, NEVER migrate a production connect to the target (ElasticSearch 7) cluster It is HIGHLY RECOMMENDED to perform a full cluster backup/snapshot of the source clusters (including ElasticSearch and Unomi clusters), and ideally to perform restored snapshot of the source cluster. For more information on ElasticSearch 5 snapshots and restore you can find it here: https://www.elastic.co/guide/en/elasticsearch/reference/5.6/modules-snapshots