Using the native date widget of the browser is now a configurable option, see config variable use_browser_date_input in section [web]. With native dates the problem is fixed but it is impossible to configure international date format server-side.

So for non-native date (when the config item above is set to 'no' which is the default) the problem is not fixed.

Note that I meanwhile think that we should really fix this in the old date widget and *not* in the date.Date and date.Interval implementations. The reason is that an interval of '1m' (one month) will always be 30 days (it is the same in pythons own implementation as was pointed out during discussions). So adding/subtracting this from the current date will often be wrong depending on the current date. Instead the prev/next links in date navigation should compute the correct date from the current date in the widget and not use '1m'.

Another option would be to integrate a 3rd-party date widget instead of fixing the ancient one we have in our code.

So I'm leaving this open for now.