4.2 doc backport has landed: https://github.com/openshift/openshift-docs/pull/17754
This change is live on docs.openshift.com, eg https://docs.openshift.com/container-platform/4.2/updating/updating-cluster-cli.html and on the portal, eg https://access.redhat.com/documentation/en-us/openshift_container_platform/4.2/html/updating_clusters/updating-cluster-cli