django/docs/releases/4.2.txt

============================================
Django 4.2 release notes - UNDER DEVELOPMENT
============================================

*Expected April 2023*

Welcome to Django 4.2!

These release notes cover the :ref:`new features <whats-new-4.2>`, as well as
some :ref:`backwards incompatible changes <backwards-incompatible-4.2>` you'll
want to be aware of when upgrading from Django 4.1 or earlier. We've
:ref:`begun the deprecation process for some features
<deprecated-features-4.2>`.

See the :doc:`/howto/upgrade-version` guide if you're updating an existing
project.

Python compatibility
====================

Django 4.2 supports Python 3.8, 3.9, 3.10, and 3.11. We **highly recommend**
and only officially support the latest release of each series.

.. _whats-new-4.2:

What's new in Django 4.2
========================

Minor features
--------------

:mod:`django.contrib.admin`
~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.admindocs`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.auth`
~~~~~~~~~~~~~~~~~~~~~~~~~~

* The default iteration count for the PBKDF2 password hasher is increased from
  390,000 to 480,000.

:mod:`django.contrib.contenttypes`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.gis`
~~~~~~~~~~~~~~~~~~~~~~~~~

* The :doc:`GeoJSON serializer </ref/contrib/gis/serializers>` now outputs the
  ``id`` key for serialized features, which defaults to the primary key of
  objects.

:mod:`django.contrib.messages`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.postgres`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* The new :lookup:`trigram_strict_word_similar` lookup, and the
  :class:`TrigramStrictWordSimilarity()
  <django.contrib.postgres.search.TrigramStrictWordSimilarity>` and
  :class:`TrigramStrictWordDistance()
  <django.contrib.postgres.search.TrigramStrictWordDistance>` expressions allow
  using trigram strict word similarity.

:mod:`django.contrib.redirects`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.sessions`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.sitemaps`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.sites`
~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.staticfiles`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.syndication`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

Cache
~~~~~

* ...

CSRF
~~~~

* ...

Decorators
~~~~~~~~~~

* ...

Email
~~~~~

* ...

Error Reporting
~~~~~~~~~~~~~~~

* ...

File Storage
~~~~~~~~~~~~

* ...

File Uploads
~~~~~~~~~~~~

* ...

Forms
~~~~~

* ...

Generic Views
~~~~~~~~~~~~~

* ...

Internationalization
~~~~~~~~~~~~~~~~~~~~

* ...

Logging
~~~~~~~

* ...

Management Commands
~~~~~~~~~~~~~~~~~~~

* :djadmin:`makemessages` command now supports locales with private sub-tags
  such as ``nl_NL-x-informal``.

* The new :option:`makemigrations --update` option merges model changes into
  the latest migration and optimizes the resulting operations.

Migrations
~~~~~~~~~~

* The new :ref:`generic mechanism <migrations-removing-operation>` allows
  handling the deprecation of migration operations.

Models
~~~~~~

* ...

Requests and Responses
~~~~~~~~~~~~~~~~~~~~~~

* ...

Security
~~~~~~~~

* ...

Serialization
~~~~~~~~~~~~~

* ...

Signals
~~~~~~~

* ...

Templates
~~~~~~~~~

* ...

Tests
~~~~~

* ...

URLs
~~~~

* ...

Utilities
~~~~~~~~~

* The new ``encoder`` parameter for :meth:`django.utils.html.json_script`
  function allows customizing a JSON encoder class.

* The private internal vendored copy of ``urllib.parse.urlsplit()`` now strips
  ``'\r'``, ``'\n'``, and ``'\t'`` (see :cve:`2022-0391` and :bpo:`43882`).
  This is to protect projects that may be incorrectly using the internal
  ``url_has_allowed_host_and_scheme()`` function, instead of using one of the
  documented functions for handling URL redirects. The Django functions were
  not affected.

Validators
~~~~~~~~~~

* ...

.. _backwards-incompatible-4.2:

Backwards incompatible changes in 4.2
=====================================

Database backend API
--------------------

This section describes changes that may be needed in third-party database
backends.

* ...

Dropped support for MariaDB 10.3
--------------------------------

Upstream support for MariaDB 10.3 ends in May 2023. Django 4.2 supports MariaDB
10.4 and higher.

Dropped support for MySQL 5.7
-----------------------------

Upstream support for MySQL 5.7 ends in October 2023. Django 4.2 supports MySQL
8 and higher.

Dropped support for PostgreSQL 11
---------------------------------

Upstream support for PostgreSQL 11 ends in November 2023. Django 4.2 supports
PostgreSQL 12 and higher.

Miscellaneous
-------------

* The undocumented ``SimpleTemplateResponse.rendering_attrs`` and
  ``TemplateResponse.rendering_attrs`` are renamed to ``non_picklable_attrs``.

* The undocumented ``django.http.multipartparser.parse_header()`` function is
  removed. Use ``django.utils.http.parse_header_parameters()`` instead.

* :ttag:`{% blocktranslate asvar … %}<blocktranslate>` result is now marked as
  safe for (HTML) output purposes.

.. _deprecated-features-4.2:

Features deprecated in 4.2
==========================

``index_together`` option is deprecated in favor of ``indexes``
---------------------------------------------------------------

The :attr:`Meta.index_together <django.db.models.Options.index_together>`
option is deprecated in favor of the :attr:`~django.db.models.Options.indexes`
option.

Migrating existing ``index_together`` should be handled as a migration. For
example::

    class Author(models.Model):
        rank = models.IntegerField()
        name = models.CharField(max_length=30)

        class Meta:
            index_together = [["rank", "name"]]

Should become::

    class Author(models.Model):
        ranl = models.IntegerField()
        name = models.CharField(max_length=30)

        class Meta:
            indexes = [models.Index(fields=["rank", "name"])]

Running the :djadmin:`makemigrations` command will generate a migration
containing a :class:`~django.db.migrations.operations.RenameIndex` operation
which will rename the existing index.

Miscellaneous
-------------

* The ``BaseUserManager.make_random_password()`` method is deprecated. See
  `recipes and best practices
  <https://docs.python.org/3/library/secrets.html#recipes-and-best-practices>`_
  for using Python's :py:mod:`secrets` module to generate passwords.

* The ``AlterIndexTogether`` migration operation is deprecated.

* The ``length_is`` template filter is deprecated in favor of :tfilter:`length`
  and the ``==`` operator within an :ttag:`{% if %}<if>` tag. For example

  .. code-block:: html+django

    {% if value|length == 4 %}…{% endif %}
    {% if value|length == 4 %}True{% else %}False{% endif %}

  instead of:

  .. code-block:: html+django

    {% if value|length_is:4 %}…{% endif %}
    {{ value|length_is:4 }}