You can access your
calendar and contacts using CalDAV and CardDAV, respectively.
First, log in to the webmail interface at https://webmail.fnoco.eu. Select the option 'Calendar' or 'Address book' in the menu in the top right of the screen:
Open the menu ⋮ next to the calendar or address book you wish to export:
Select
the option "Links for this calendar / address book". A window with a
number of URLs will open - The first entry is best suited for read/write
use in mail clients. You can use the same login details as for the web
mail interface, i.e. your full email address as username.