Just FYI this is a third party solution that works very well. https://www.mailstore.com/

With Mailstore you choose how often you run an archive (or automate the process) and allow the user IMAP access to their archived email. We have found that in a number of instances the IMAP connection to Mailstore performs better than the Kerio connection but that'll come down to your server specs.


I too would have preferred something built into Kerio but we've used a virtualised instance of Mailstore at a number our clients and it works very well.

p.s I am not affiliated in anyway with Mailstore.