Hello! > So 'mm' means month or day depending on the context. Thus: [...] > 1984-04-04/06 the 4th through 6th of April 1984. This would be quite problematic, because our L2Interval may contain an L2Date (not only ISO 8601 dates). Let's consider: 189u-02-08/29 How long would such an interval be? Three weeks? A little more than seven years? Of course, we could allow a construction like 189u-02-08/29 but in this case, we should need to be quite clear about its interpretation. We could also stick with yyyy-mm-dd/yyy-mm-dd even when both the year and the month is the same on both side, but this could be problematic too. Let's consider 189u-02-08/22 which obviously is two weeks long whereas 189u-02-08/189u-02-22 may be two weeks or several years long. Regards! SaaĊĦha,