Hi,
yes we did change calendar system, so that one event can be attached to more calendars. So we had to add table for many to many relation, therefor CalendarId field is no longer on event entity. You need to change your filter code like this
filter.Relations.Add(CalendarEventEntity.Relations.CalendarEventEntryEntityUsingCalendarEventId);
filter.PredicateExpression.Add(CalendarEventEntryFields.CalendarId ==
this
.CalendarId);
this should fix error you get.