code: private void writeExceptions(Project.Calendars.Calendar calendar, List<Project.Calendars.Calendar.WeekDays.WeekDay> dayList, List<ProjectCalendarException> exceptions)
     {
        // Always write legacy exception data:
        // Powerproject appears not to recognise new format data at all,
        // and legacy data is ignored in preference to new data post MSP 2003
        writeExceptions9(dayList, exceptions);
  
        if (m_saveVersion.getValue() > SaveVersion.Project2003.getValue())
        {
           writeExceptions12(calendar, exceptions);
        }
     }
docs: Main entry point used to determine the format used to write
  calendar exceptions.
  
  @param calendar parent calendar
  @param dayList list of calendar days
  @param exceptions list of exceptions