I used the Outlook CalDav Synchronizer to sync a calendar with dokuwiki. However, it is not working any longer. I assume that this error coincides with the update to Elenor of Tsort, but I am not shure about that. I tried to sync with another caldav server, which works fine. I also tried to sync the davcal calender with thunderbird (using the lightning addon) and it works. So it seems to be a special problem when Outlook CalDav Synchronizer and Davcal are used together. The log files of my webserver running dokuwiki confirm, that Outlook CalDav Synchronizer sends the report-command.
I can look deeper in the logfiles or maybe capture the request send to davcal, but I would need further instruction about where to look at.