      my_queryset.defer(None)
  
  .. versionchanged:: 1.5
  
  Some fields in a model won't be deferred, even if you ask for them. You can
  never defer the loading of the primary key. If you are using
  :meth:`select_related()` to retrieve related models, you shouldn't defer the
  loading of the field that connects from the primary model to the related
  one, doing so will result in an error.
  
  .. note::
  
      The ``defer()`` method (and its cousin, :meth:`only()`, below) are only for
      advanced use-cases. They provide an optimization for when you have analyzed
 
</s> remove In Python 3, the logic is reversed, that is normal strings are Unicode, and
when you want to specifically create a bytestring, you have to prefix the
string with a 'b'. As we are doing in Django code from version 1.5,
we recommend that you import ``unicode_literals`` from the __future__ library
in your code. Then, when you specifically want to create a bytestring literal,
prefix the string with 'b'.
 </s> add     In Python 3, the logic is reversed, that is normal strings are Unicode, and
    when you want to specifically create a bytestring, you have to prefix the
    string with a 'b'. As we are doing in Django code from version 1.5,
    we recommend that you import ``unicode_literals`` from the __future__ library
    in your code. Then, when you specifically want to create a bytestring literal,
    prefix the string with 'b'. </s> remove As of Django 1.7, when :class:`HttpResponse` is instantiated with an
iterator, it will consume it immediately, store the response content as a
string, and discard the iterator.
 </s> add     As of Django 1.7, when :class:`HttpResponse` is instantiated with an
    iterator, it will consume it immediately, store the response content as a
    string, and discard the iterator. </s> remove options. Also note that using :meth:`only` and omitting a field requested
using :meth:`select_related` is an error as well.
 </s> add options. </s> remove The behavior by which introspected models are created as unmanaged ones is new
in Django 1.6.
 </s> add     The behavior by which introspected models are created as unmanaged ones is new
    in Django 1.6. </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.
    Some fields in a model won't be deferred, even if you ask for them. You can
    never defer the loading of the primary key. If you are using
    :meth:`select_related()` to retrieve related models, you shouldn't defer the
    loading of the field that connects from the primary model to the related
    one, doing so will result in an error.
      my_queryset.defer(None)
  
  .. versionchanged:: 1.5
  
    Some fields in a model won't be deferred, even if you ask for them. You can
    never defer the loading of the primary key. If you are using
    :meth:`select_related()` to retrieve related models, you shouldn't defer the
    loading of the field that connects from the primary model to the related
    one, doing so will result in an error.
    Some fields in a model won't be deferred, even if you ask for them. You can
    never defer the loading of the primary key. If you are using
    :meth:`select_related()` to retrieve related models, you shouldn't defer the
    loading of the field that connects from the primary model to the related
    one, doing so will result in an error.
    Some fields in a model won't be deferred, even if you ask for them. You can
    never defer the loading of the primary key. If you are using
    :meth:`select_related()` to retrieve related models, you shouldn't defer the
    loading of the field that connects from the primary model to the related
    one, doing so will result in an error.
    Some fields in a model won't be deferred, even if you ask for them. You can
    never defer the loading of the primary key. If you are using
    :meth:`select_related()` to retrieve related models, you shouldn't defer the
    loading of the field that connects from the primary model to the related
    one, doing so will result in an error.
    Some fields in a model won't be deferred, even if you ask for them. You can
    never defer the loading of the primary key. If you are using
    :meth:`select_related()` to retrieve related models, you shouldn't defer the
    loading of the field that connects from the primary model to the related
    one, doing so will result in an error.
  
  .. note::
  
      The ``defer()`` method (and its cousin, :meth:`only()`, below) are only for
      advanced use-cases. They provide an optimization for when you have analyzed
keep keep keep keep replace replace replace replace replace keep keep keep keep keep
 Adapted uses of versionchanged/versionadded to the new form.

Refs #20104. 
docs/ref/models/querysets.txt