Usually, an operation that retrieves a queryset of pages (such as ``homepage.get_children()``) will return them as basic Page instances, which only include the core page data such as title. The ``specific()`` method (e.g. ``homepage.get_children().specific()``) now allows them to be retrieved as their most specific type, using the minimum number of queries.
The Elasticsearch search backend now accepts an experimental ``ATOMIC_REBUILD`` flag which ensures that the existing search index continues to be available while the ``update_index`` task is running. See :ref:`wagtailsearch_backends_atomic_rebuild`.
The ``wagtailapi`` module is now built on Django REST Framework and it now also has a `library of serialisers <https://github.com/wagtail/wagtail/blob/stable/1.1.x/wagtail/contrib/wagtailapi/serializers.py>`_ that you can use in your own REST Framework based APIs. No user-facing changes have been made.
Snippets that inherit from ``wagtail.wagtailsearch.index.Indexed`` are now given a search box on the snippet chooser and listing pages. See :ref:`wagtailsnippets_making_snippets_searchable`.
* Search backends can now be specified by module (e.g. ``wagtail.wagtailsearch.backends.elasticsearch``), rather than a specific class (``wagtail.wagtailsearch.backends.elasticsearch.ElasticSearch``)
* Added aliases for the ``self`` template variable to accommodate Jinja as a templating engine: ``page`` for pages, ``field_panel`` for field panels / edit handlers, and ``value`` for blocks
* Added ability to mark page models as not available for creation using the flag ``is_creatable``; pages that are abstract Django models are automatically made non-creatable
* The queryset returned from ``search`` operations when using the database search backend now correctly preserves additional properties of the original query, such as ``prefetch_related`` / ``select_related``
* Form builder pages now pick up template variables defined in the ``get_context`` method
* When copying a page, IDs of child objects within page revision records were not remapped to the new objects; this would cause those objects to be lost from the original page when editing the new one
Previous versions of Wagtail provided an undocumented ``is_abstract`` flag on page models - not to be confused with Django's ``abstract`` Meta flag - to indicate that it should not be included in the list of available page types for creation. (Typically this would be used on model classes that were designed to be subclassed to create new page types, rather than used directly.) To avoid confusion with Django's distinct concept of abstract models, this has now been replaced by a new flag, ``is_creatable``.
If you have used ``is_abstract = True`` on any of your models, you should now change this to ``is_creatable = False``.
It is not necessary to include this flag if the model is abstract in the Django sense (i.e. it has ``abstract = True`` in the model's ``Meta`` class), since it would never be valid to create pages of that type.
