The CalDAV functionality was originally developed as an extension of the calendar package in 2006 by Gustaf Neumann [1], then extended by Hubert Stickelberger and Nermin Topcagic in 2014 while working on their master theses, further maintained and extended by Markus Moser, and refactored and fixed again by Gustaf Neumann in 2019, extended by regression tests emulating clients from Android, iOS and Thunderbird. Currently, the package contains 394 tests for regression testing.
The package does not depend on DotLRN, but uses some of its features, when it is installed.