At the moment you can only choose from a fixed list of options:
Every Day, Every Month, Every Weekday, Every Week, Every Two Weeks, Every Four Weeks
The resulting code looks like this:
[event start="2023-12-01 10:30" status="public" timezone="Europe/Berlin" recurrence="every_week" end="2023-12-01 11:00" allowedGroups="trust_level_0"]
[/event]
It is not allowed to use other values for the recurrence attribute than the ones mentioned above (an error will be displayed).
Please let users define other recurrence patterns like every second monday, yearly or within a date-range
“Every second monday” could be set by a recurrence rule like FREQ=MONTHLY;COUNT=12;BYDAY=2MO following rfc5545 specification
I’ve noticed this PR which already makes use of the rfc5545 rules.