https://bugzilla.redhat.com/show_bug.cgi?id=1912238

 
Document URL:
https://docs.openshift.com/container-platform/4.6/logging/cluster-logging-upgrading.html
Section Number and Name:
Updating cluster logging

Describe the issue:
The Prerequisites section says that "Back up your Elasticsearch and Kibana data.", so backing up and restoring procedures should be described. Or could this sentence remove from the document?

Suggestions for improvement:
Add information that backing up and restoring the es and kibana data