First thing to note is that Ubuntu 18.04 is a Long Term Service release, and
will be supported until 2023. So no matter how naggy Ubuntu is, you don't
actually HAVE to upgrade at this point. You may disable the prompt if if bothers
you: just remove or comment out the relevant file in /etc/update-motd.d/
Now the pressure is off, and you have a bit more time, maybe the best idea would
be to build and configure a new server using Ubuntu 20, or any other distro, and
then migrate the data over to it with dsync. That affords you an opportunity to
test the new config before one final sync, and switching the MX records to point
to the new server.
If for any reason you are locked into upgrading the current server, the only
advice I can offer from a recent dovecot migration between an Ubuntu 18 server
and a Ubuntu 20 server, was that the default SSL settings are considerably
improved, which meant that a lot of the clients, who were using ancient versions
of Outlook, were unable to connect. I needed to downgrade the security (against
my better judgement) in order to let them connect, commenting out the line
# ssl_min_protocol=TLSv1.2
so that it defaulted to TLSv1. You might wish to bear this in mind, although any
modern email client won't have any problems.
Good luck!
P.
On 08/07/2021 09.15, Shawn Heisey wrote:> I have a mail server in AWS that is currently running Ubuntu 18.? Every
time I log in, I am reminded that I can upgrade to Ubuntu 20.
>
> On Ubuntu 18, the dovecot version is 3.3.0-1ubuntu0.3.? On Ubuntu 20, it is
2.3.7.2-1ubuntu3.? Many other packages, probably including the mysql server,
would also be upgraded.
>
> Dovecot and Postfix use a postfixadmin database in mysql for users, and
postfix is using dovecot-lda to deliver mail.? I am using managesieve from
dovecot on roundcube webmail.? As far as I know, my own user is the only one
with sieve scripts actually in use ... and I have a LOT of filters/folders for
various mailing lists.
>
> I've been a little bit terrified of doing an upgrade, because I do have
a couple of people using my mail server for real work email and I don't want
to disrupt them.
>
> I'm writing today to find out what are the likely pain points I might
encounter when doing this kind of major upgrade, and if there is any helpful
information that can help me get through those problems.? I'm hoping that it
will go smoothly and everything just works.
>
> Here's the doveconf -n output:
> https://apaste.info/FUgF
>
> If I have been silly enough to include sensitive data from the config, I
would appreciate a heads up so I know what passwords to change.? I did a quick
glance and didn't see anything.
>
> Thanks,
> Shawn