This is the source repository for the Baïkal CalDAV and CardDAV server.
Head to sabre.io/baikal for information about installation, upgrading and troubleshooting.
A German tutorial about installation of Baïkal, using it together with Thunderbird, Android and DavX5, sharing calendars, database maintenance and security can be found here. Its focus is for people with not so much IT experience. Therefore it is very detailed, step by step with a RaspberryPI used as server.
Please follow the upgrade instructions.