Note: Produce a file less than /and so forth/apt/resources.list.d, not the /and so on/apt/sources.checklist file the place the distribution's official repository addresses can be found. This can be a system that will not destabilize your program. It is usually recommended. MX document is yet another sort of document included https://bookmarkspiral.com/story17017048/everything-about-dovecot-install