Which versions of Orchestrator is Elaticsearch version 7.x compatible with?
Elasticsearch version 7.x is only compatible with 2019.10 and above versions of Orchestrator. Major changes in the way how Elasticsearch works to read requests, has made the same version not compatible with older versions, such as Orchestrator 2019.4.x and below. For these versions, the only compatible version of Elasticsearch is 6.x and below.
For more clarification, it is best to validate the software requirements (https://docs.uipath.com/orchestrator/docs/software-requirements) page for the respective versions of Orchestrator that is being used.