We just upgraded a 7.9.1 cluster with 47.3.0 to 7.10.2 with 53.0.0.
The upgrade went well, but kibana wasn’t happy : after startup (kibana 7.10.2 with 51.0.0) we get “Application not found” when trying to access the multi-tenancy page. Also, it doesn’t appear in menu anymore.
Here also a kibana log entry which may be related:
Mar 30 18:55:32.862 node42 kibana: [security_exception]: no permissions for [indices:monitor/settings/get] and User kibanaserver <basic/internal>