define calendar components during collection creation
The apple applications seems to dislike collections with mixed content, the like to separate their content (VEVENT, VTODO...). for the default collections I resolved this issue in the configuration:
$c->default_collections = array( array( ... 'calendar_components'=>array('VEVENT'), ... ), );
but creating a collection manually via web interface results in a collection which can hold everything. Would it be possible to add checkboxes, where you can choose which components are used in a collection?
Some generation of apple clients just Ignore those collections, some simply created new ones, some didn't work at all if such a collection existed.