I have one more problem: I tried to upgrade Roundcube to 1.3.1. I downloaded the package and ran the installto.sh script, towards my roundcube 1.2.4 installation (from iRedMail 0.9.6). I had some problems with crypt_gpg at first, but I solved them with the help of the Internet.
The last remaining problem is: my enigma plugin isn't working. I've ran
php composer.phar update --no-dev
and updated all plugins, including enigma. However, when I go to the "PGP Keys" page in the settings, I get the following error:
Application Error (600): Enigma plugin: Keys directory isn't writeable: /opt/www/roundcubemail/plugins/enigma/home
However, I've set the folder access to be exactly like it was in my 1.2.4 installation of roundcube (I've kept a backup):
# ll plugins/enigma/home/ -a
drwxr-xr-x 5 root root 4096 Oct 30 00:01 .
drwxr-xr-x 7 root root 4096 Oct 30 19:22 ..
drwx------ 2 root root 4096 Apr 30 2017 firstname.lastname@example.org
-rw-r--r-- 1 root root 164 Sep 4 19:03 .htaccess
Again, this is identical to how the permissions looked before the update, and PGP keys and signing used to work.