DAVx⁵ has been successfully tested with Radicale.

The Radicale Project is a complete CalDAV (calendar) and CardDAV (contact) server solution. It aims to be a light solution, easy to use, easy to install, easy to configure.

DAVx⁵ settings

Base URL: / (e.g. https://example.com/radicale/)

Radicale v2.x: If well-known URLs are not configured (well-known section in configuration file), you can try /user/ (e.g. https:// server.example/radicale/user/).

Radicale v3.x: well-known URLs should be automatically working out-of-the-box.

Contact group method: groups are separate VCards (or the method used by your other clients)

Server setup

If you're proxying Radicale with a base path, e.g. /radicale/ instead of just /, make sure that base_prefix is set correctly in your server configuration!

You might also have to set up well-known URLs on your forwarding proxy.