  
          In older versions, the ``Last-Modified`` header was also set.
  
  .. function:: add_never_cache_headers(response)
  
      Adds a ``Cache-Control: max-age=0, no-cache, no-store, must-revalidate``
      header to a response to indicate that a page should never be cached.
  
 
</s> remove or you can rely on the :class:`~django.middleware.common.CommonMiddleware`
 </s> add or you can rely on the :class:`~django.middleware.http.ConditionalGetMiddleware` </s> remove Handles conditional GET operations. If the response has a ``ETag`` or
 </s> add Handles conditional GET operations. If the response doesn't have an ``ETag``
header, the middleware adds one if needed. If the response has a ``ETag`` or
    .. deprecated:: 1.11

        Since the ``USE_ETAGS`` setting is deprecated, this function won't set
        the ``ETag`` header when the deprecation ends in Django 2.1.

  
          In older versions, the ``Last-Modified`` header was also set.
  
    .. deprecated:: 1.11

        Since the ``USE_ETAGS`` setting is deprecated, this function won't set
        the ``ETag`` header when the deprecation ends in Django 2.1.

  .. function:: add_never_cache_headers(response)
  
      Adds a ``Cache-Control: max-age=0, no-cache, no-store, must-revalidate``
      header to a response to indicate that a page should never be cached.
  
keep keep add keep keep keep keep keep
 Fixed #26447 -- Deprecated settings.USE_ETAGS in favor of ConditionalGetMiddleware. 
docs/ref/utils.txt