[Dovecot] systemd socket and service

[Michal Hlavinka]

> > > 2) Does dovecot.service required to use dovecot lmtp, or it may be
> > > stoppped (i not often check my mails via client, but have many incoming
> > > mails some time)
> > 
> > I don't understand. If you want LMTP enabled, you also need to list its
> > socket to dovecot.socket. LMTP is executed in a similar way to
> > IMAP/POP3. (If you want LMTP via UNIX socket, I don't really know the
> > answer to that. Does systemd support listening on UNIX sockets? Maybe
> > it requires patching Dovecot more.)
> 
> I'm not fully understand how can i do that and not lost my changes to
> dovecot.socket when the packages updates and file has been rewritten...

packages should install systemd socket/service files in /lib/systemd/.... if you want to 
change any file, you should copy it to /etc/systemd/... and modify it there.
systemd prefers files in /etc/systemd over those in /lib/systemd