If you have a cluster, you will have almost 'no' downtime. First upgrade the first appliance, it will continue to deliver mail during the upgrade, you only have some downtime while the system is rebooting. Then upgrade the second.If you do have a clu...
You can also use a group query for this, create a mail policy where the sender address must exist in a group and drop() all messages from the default outgoing mail policy.
I would recommend to upgrade your system, the findevent command is not available in your system, neither are lots of other improvements, features and bugfixes. You cannot upgrade straight to 6.5.1 from your version, you probably have to upgrade multi...
