Problems with updating Roundcube

I recently upgraded roundcube following the usual automated prompts from the software updater. This causes two problems:

1. Apart from roundcube itself I had to install roundcube-plugins and roundcube-sqlite3.
2. The DB access was now set to 'no password' causing all db connections to fail. I had to edit /etc/roundcube/debian-db.php by hand to get connections to work. Editing /etc/dbconfig-common/roundcube.conf and then running dpkg-reconfigure did not work. (As of 18.04 this seems to be fixed.)
3. The php mcrypt module was not properly enabled. I had to run 'php5enmod mcrypt' by hand to get things working again.
4. The installer now prompts you for which database you want. I have switched to sqlite3 as the access is almost entirely read-only. This prompting only happens on a clean install; if there is a residual old system lying around the installer tries to guess.
5. I have set courier-imap to listen on 0.0.0.0, and then in main.inc 'default_host' is set to localhost.

Description: Ubuntu 16.04.6 LTS