  * Writable nested serializers.
  * List/detail routes.
  * 1.3 Support dropped, install six for <=1.4.?.
  * `allow_none` for char fields
 
</s> remove         try:
            lookup_value = viewset.lookup_value_regex
        except AttributeError:
            # Don't consume `.json` style suffixes
            lookup_value = '[^/.]+'
 </s> add         lookup_value = getattr(viewset, 'lookup_value_regex', '[^/.]+')
* `trailing_slash = True` --> `[^/]`, `trailing_slash = False` --> `[^/.]`, becomes simply `[^/]` and `lookup_value_regex` is added.
  * Writable nested serializers.
  * List/detail routes.
  * 1.3 Support dropped, install six for <=1.4.?.
  * `allow_none` for char fields
* `trailing_slash = True` --> `[^/]`, `trailing_slash = False` --> `[^/.]`, becomes simply `[^/]` and `lookup_value_regex` is added.
keep keep keep add
 Minor tweaks to 'lookup_value_regex' work 
docs/topics/2.4-accouncement.md