Import mail from Exim installation to iRedMail

==== Required information ====
- iRedMail version: 0.9.1
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MariaDB
- Web server (Apache or Nginx): Nginx
- Linux/BSD distribution name and version:  Debian Jessie
- Related log if you're reporting an issue:
====

Hey,

I have one mail server with dovecot / exim4 personal installation. Now i have fresh iRedMail on one other server.

I Would like import all my mails from my old mail server to iRedMail.

Is it possible ?

Thank you