You must import data from Kibana dashboard before upgrading to Sentinel 8.6.1
To import data from Kibana Dashboard:
Navigate to Management on Opensearch Dashboard and click Stack Management.
Click Saved Objects under Opensearch Dashboard.
Click on Import when prompted to select a file to upload. Select the export.ndjson file that was generated while exporting data from Kibana Dashboards for more details, see Exporting Data from Kibana Dashboard to Opensearch Dashboard.
Click Open and select an import option. Select from the Overwrite or Recreate option as per your requirement.
Click Import to import all the saved objects exported from Kibana Dashboard.