I was trying a scenario where I can export all my messages/conversation to a zip file. I found this feature mentioned in the feature list of ZCS 4.5.6 but actually could find the steps to do this. I am using the Zimbra Web Client(4.5.6). I found the feature to import/export contacts from/to .csv file respectively, but could not find any UI component(in web client) to export messages and/or conversations.

Is this feature supported in 4.5.6 or a feature of 5.0 ?
Is this a paid feature?