When using current Winterfall, searching for appointments in Roundcube doesn't work. There is no error in the web frontend, however also "no obvious search attempt" and also no visible error message. I also wasn't able to see an obvious error message in the logs, but last should be verified for sure. To avoid misunderstandings: I'm using the search input box in the upper right corner when being on the calendar "screen" in Roundcube.

As talked with @vanmeeuwen on IRC, he's able to reproduce it, "but it's easier to close a duplicate than it is to go after all unlogged tickets" - thus filed hereby ;-)