if the address currently pointing to your HiveMQ CE is a load balancer,
you have the option of bringing up your Enterprise Edition cluster and then
over traffic to the new brokers. All current sessions on the CE broker will
and the clients will need to reconnect.
Should the IP address point to the host that will be home to the newly
Enterprise Edition broker you will first need to shut down the CE and then
up its replacement.
In either case the current state of the broker (client sessions /
subscriptions / queued messages
and retained messages) will not be transferred.
A workaround for migrating retained messages would be to subscribe to # on
running broker, storing all messages (and corresponding topics) and then
them on the new cluster.
I hope this helps.