I have build my first mail server back in 2014 following series of articles from :
that is running on AWS (Ubuntu 12.04.5 LTS).
It has only one domain with 3 users, and I would like to move it to MIAB running on another VPS as a new mail users on existing MIAB already running other domains …
What would be the best way to go about it without loosing all the e-mails please?