  If fields in the serialized data do not exist on a model,
  a ``DeserializationError`` will be raised unless the ``ignorenonexistent``
  argument is passed in as True::
  
      serializers.deserialize("xml", data, ignorenonexistent=True)
  
  .. _serialization-formats:
  
  Serialization formats
  ---------------------
 
</s> remove If fields in the serialized data do not exist on a model,
a ``DeserializationError`` will be raised unless the ``ignorenonexistent``
argument is passed in as True::
 </s> add     If fields in the serialized data do not exist on a model,
    a ``DeserializationError`` will be raised unless the ``ignorenonexistent``
    argument is passed in as True:: </s> remove In previous versions of Django, the ``pk`` attribute had to be present
on the serialized data or a ``DeserializationError`` would be raised.
 </s> add     In previous versions of Django, the ``pk`` attribute had to be present
    on the serialized data or a ``DeserializationError`` would be raised. </s> remove The current value of the field will be displayed as a clickable link above the
input widget.
 </s> add     The current value of the field will be displayed as a clickable link above the
    input widget. </s> remove             The ``content_type`` attribute was added.
 </s> add  </s> remove If a backend raises a :class:`~django.core.exceptions.PermissionDenied`
exception, authentication will immediately fail. Django won't check the
backends that follow.
 </s> add     If a backend raises a :class:`~django.core.exceptions.PermissionDenied`
    exception, authentication will immediately fail. Django won't check the
    backends that follow.
        serializers.deserialize("xml", data, ignorenonexistent=True)
  If fields in the serialized data do not exist on a model,
  a ``DeserializationError`` will be raised unless the ``ignorenonexistent``
  argument is passed in as True::
  
        serializers.deserialize("xml", data, ignorenonexistent=True)
  
  .. _serialization-formats:
  
  Serialization formats
  ---------------------
keep keep keep keep replace keep keep keep keep keep
 Adapted uses of versionchanged/versionadded to the new form.

Refs #20104. 
docs/topics/serialization.txt