The process of rolling upgrade has changed for RHDG 7.x.

It is not longer necessary to dump the keys:
JMX : Invoke the recordKnownGlobalKeyset
CLI : Invoke the upgrade --dumpkeys command on the Source Cluster for every cache that must be migrated

If the method is invoked it might cause Marshalling error messages !

The methods should be removed or print a (error) message to not confuse the user during migration as it can be skipped