'Return whether an update of a given magnitude has occured
to the parent document since this translation had an approved
update and such revision is ready for l10n.
If this is not a translation or has never been approved, return
False.
level: The significance of an edit that is "enough". Defaults to
MEDIUM_SIGNIFICANCE.'

def is_outdated(self, level=MEDIUM_SIGNIFICANCE):

    if (not (self.parent and self.current_revision)):
        return False
    based_on_id = self.current_revision.based_on_id
    more_filters = ({'id__gt': based_on_id} if based_on_id else {})
    return self.parent.revisions.filter(is_approved=True, is_ready_for_localization=True, significance__gte=level, **more_filters).exists()
