Two users reported an issue via mail that installation of webdavclient/davcal fail with "SQLite: no DB version found. 'davcal' DB probably broken.".
Investigations have shown that there is also an error in the web server log: "Uncaught Error: Call to a member function process_event() on boolean in /srv/http/doku/inc/events.php:70"
It seems to be related to a recent update of SQLite that added an event in the initialization stage. The following github issue tracks the problem: https://github.com/cosmocode/sqlite/issues/43