Howtoforge published a tutorial about how to install Radicale Calendar (CalDAV and CardDAV) on Ubuntu 20.04.

How to Install Radicale Calendar (CalDAV and CardDAV) on Ubuntu 20.04

Radicale is a free and open-source CalDAV (Calendars, to-do lists) and CardDav (contacts) server. It aims to be a small and lightweight (CalDAV and CardDav) server application, yet powerful and works out-of-the-box. Radicale allows you to shares calendars and contact lists through CalDAV, CardDAV, and HTTPS. And most importantly, it can be secure through TLS connection and authentication. Also, it works with many CalDAV and CardDAV clients such as gnome-calendar, evolution, Mozilla thunderbird, DAVx (for android), etc.

How to Install Radicale Calendar (CalDAV and CardDAV) on Ubuntu 20.04