Remove ambari-log4j package that is no longer used from the ambari-server host.

yum remove ambari-log4j

Restart Ambari server after the Express Upgrade has been finalized and migration is complete.

ambari-server restart

Upgrade bigtop-tomcat for Oozie

	Important
	If upgrading from IOP- 4.2.0, Oozie start will fail due to the incompatible C version 6.0.36-3.el6 installed from the IOP-4.2.0 repo. You must upgrade bigtop-tomcat to version 6.0.48-1 provided by HDP-2.6.4 repo. Perform upgrade of bigtop-tomcat on all hosts where Oozie server is installed. yum upgrade bigtop-tomcat

Regenerate Keytabs for All Services

	Important
	If the cluster is kerberized, regenerate keytabs for all services after the upgrade.

(Optional) Add Grafana

If upgrading from IOP- 4.2.0, and if you did not add Grafana after upgrading Ambari, Grafana does not exist as a component in your cluster.

You can add Grafana using the following set of instructions:

Add Grafana to Ambari Metrics