I upgraded from 5.1, which upgrades Ubuntu to 18.04LTS.
dpkg fails with:
...
fetchmail: no mailservers have been specified.
...
This causes all of the Zentyal mail packages to fail to configure. The upgrade is stuck at around 98% completion...
I don't use any fetches from other mail servers, and probably never will, so of course no mailservers are configured!
How can I get around this?