Fixed #14656 -- Added Atom1Feed published element

Some feed aggregators make use of the `published` element as well as
the `updated` element (within the Atom standard -- http://bit.ly/2YySb).

The standard allows for these two elements to be present in the same
entry. `Atom1Feed` had implemented the `updated` element which was
incorrectly taking the date from `pubdate`.

docs/ref/contrib/syndication.txt

@@ -815,6 +815,24 @@ This example illustrates all possible attributes and methods for a
 
         item_pubdate = datetime.datetime(2005, 5, 3) # Hard-coded pubdate.
 
+        # ITEM UPDATED -- It's optional to use one of these three. This is a
+        # hook that specifies how to get the updateddate for a given item.
+        # In each case, the method/attribute should return a Python
+        # datetime.datetime object.
+
+        def item_updateddate(self, item):
+            """
+            Takes an item, as returned by items(), and returns the item's
+            updateddate.
+            """
+
+        def item_updateddate(self):
+            """
+            Returns the updateddated for every item in the feed.
+            """
+
+        item_updateddate = datetime.datetime(2005, 5, 3) # Hard-coded updateddate.
+
         # ITEM CATEGORIES -- It's optional to use one of these three. This is
         # a hook that specifies how to get the list of categories for a given
         # item. In each case, the method/attribute should return an iterable
@@ -928,16 +946,22 @@ They share this interface:
     * ``categories``
     * ``item_copyright``
     * ``ttl``
+    * ``updateddate``
 
     Extra keyword arguments will be stored for `custom feed generators`_.
 
     All parameters, if given, should be Unicode objects, except:
 
     * ``pubdate`` should be a Python  :class:`~datetime.datetime` object.
+    * ``updateddate`` should be a Python  :class:`~datetime.datetime` object.
     * ``enclosure`` should be an instance of
       :class:`django.utils.feedgenerator.Enclosure`.
     * ``categories`` should be a sequence of Unicode objects.
 
+    .. versionadded:: 1.7
+
+        The optional ``updateddate`` argument was added.
+
 :meth:`.SyndicationFeed.write`
     Outputs the feed in the given encoding to outfile, which is a file-like object.
 

docs/ref/utils.txt

@@ -342,11 +342,15 @@ SyndicationFeed
         All parameters should be Unicode objects, except ``categories``, which
         should be a sequence of Unicode objects.
 
-    .. method:: add_item(title, link, description, [author_email=None, author_name=None, author_link=None, pubdate=None, comments=None, unique_id=None, enclosure=None, categories=(), item_copyright=None, ttl=None, **kwargs])
+    .. method:: add_item(title, link, description, [author_email=None, author_name=None, author_link=None, pubdate=None, comments=None, unique_id=None, enclosure=None, categories=(), item_copyright=None, ttl=None, updateddate=None, **kwargs])
 
         Adds an item to the feed. All args are expected to be Python ``unicode``
-        objects except ``pubdate``, which is a ``datetime.datetime`` object, and
-        ``enclosure``, which is an instance of the ``Enclosure`` class.
+        objects except ``pubdate`` and ``updateddate``, which are ``datetime.datetime``
+        objects, and ``enclosure``, which is an instance of the ``Enclosure`` class.
+
+        .. versionadded:: 1.7
+
+            The optional ``updateddate`` argument was added.
 
     .. method:: num_items()
 
@@ -380,8 +384,9 @@ SyndicationFeed
 
     .. method:: latest_post_date()
 
-        Returns the latest item's ``pubdate``. If none of them have a
-        ``pubdate``, this returns the current date/time.
+        Returns the latest ``pubdate`` or ``updateddate`` for all items in the
+        feed. If no items have either of these attributes this returns the
+        current date/time.
 
 Enclosure
 ---------