django/docs/releases/4.1.txt

============================================
Django 4.1 release notes - UNDER DEVELOPMENT
============================================

*Expected August 2022*

Welcome to Django 4.1!

These release notes cover the :ref:`new features <whats-new-4.1>`, as well as
some :ref:`backwards incompatible changes <backwards-incompatible-4.1>` you'll
want to be aware of when upgrading from Django 4.0 or earlier. We've
:ref:`begun the deprecation process for some features
<deprecated-features-4.1>`.

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

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

Django 4.1 supports Python 3.8, 3.9, and 3.10. We **highly recommend** and only
officially support the latest release of each series.

.. _whats-new-4.1:

What's new in Django 4.1
========================

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

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

* The admin :ref:`dark mode CSS variables <admin-theming>` are now applied in a
  separate stylesheet and template block.

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

* ...

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

* The default iteration count for the PBKDF2 password hasher is increased from
  320,000 to 390,000.

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

* ...

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

* The new :meth:`.GEOSGeometry.make_valid()` method allows converting invalid
  geometries to valid ones.

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

* ...

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

* The new :class:`BitXor() <django.contrib.postgres.aggregates.BitXor>`
  aggregate function returns an ``int`` of the bitwise ``XOR`` of all non-null
  input values.

* :class:`~django.contrib.postgres.indexes.SpGistIndex` now supports covering
  indexes on PostgreSQL 14+.

* :class:`~django.contrib.postgres.constraints.ExclusionConstraint` now
  supports covering exclusion constraints using SP-GiST indexes on PostgreSQL
  14+.

* The new ``default_bounds`` attribute of :attr:`DateTimeRangeField
  <django.contrib.postgres.fields.DateTimeRangeField.default_bounds>` and
  :attr:`DecimalRangeField
  <django.contrib.postgres.fields.DecimalRangeField.default_bounds>` allows
  specifying bounds for list and tuple inputs.

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

* ...

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

* ...

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

* The default sitemap index template ``<sitemapindex>`` now includes the
  ``<lastmod>`` timestamp where available, through the new
  :meth:`~django.contrib.sitemaps.Sitemap.get_latest_lastmod` method. Custom
  sitemap index templates should be updated for the adjusted :ref:`context
  variables <sitemap-index-context-variables>`.

: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
~~~~~~~~~~~~~~~~~~~

* :option:`makemigrations --no-input` now logs default answers and reasons why
  migrations cannot be created.

Migrations
~~~~~~~~~~

* ...

Models
~~~~~~

* ...

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

* ...

Security
~~~~~~~~

* ...

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

* ...

Signals
~~~~~~~

* ...

Templates
~~~~~~~~~

* ...

Tests
~~~~~

* A nested atomic block marked as durable in :class:`django.test.TestCase` now
  raises a ``RuntimeError``, the same as outside of tests.

URLs
~~~~

* ...

Utilities
~~~~~~~~~

* ...

Validators
~~~~~~~~~~

* ...

.. _backwards-incompatible-4.1:

Backwards incompatible changes in 4.1
=====================================

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

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

* ``BaseDatabaseFeatures.has_case_insensitive_like`` is changed from ``True``
  to ``False`` to reflect the behavior of most databases.

* ``DatabaseIntrospection.get_key_columns()`` is removed. Use
  ``DatabaseIntrospection.get_relations()`` instead.

Dropped support for MariaDB 10.2
--------------------------------

Upstream support for MariaDB 10.2 ends in May 2022. Django 4.1 supports MariaDB
10.3 and higher.

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

* Related managers for :class:`~django.db.models.ForeignKey`,
  :class:`~django.db.models.ManyToManyField`, and
  :class:`~django.contrib.contenttypes.fields.GenericRelation` are now cached
  on the :class:`~django.db.models.Model` instance to which they belong.

* The Django test runner now returns a non-zero error code for unexpected
  successes from tests marked with :py:func:`unittest.expectedFailure`.

.. _deprecated-features-4.1:

Features deprecated in 4.1
==========================

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

* The context for sitemap index templates of a flat list of URLs is deprecated.
  Custom sitemap index templates should be updated for the adjusted
  :ref:`context variables <sitemap-index-context-variables>`, expecting a list
  of objects with ``location`` and optional ``lastmod`` attributes.

Features removed in 4.1
=======================

These features have reached the end of their deprecation cycle and are removed
in Django 4.1.

See :ref:`deprecated-features-3.2` for details on these changes, including how
to remove usage of these features.

* Support for assigning objects which don't support creating deep copies with
  ``copy.deepcopy()`` to class attributes in ``TestCase.setUpTestData()`` is
  removed.

* Support for using a boolean value in
  :attr:`.BaseCommand.requires_system_checks` is removed.

* The ``whitelist`` argument and ``domain_whitelist`` attribute of
  ``django.core.validators.EmailValidator`` are removed.

* The ``default_app_config`` application configuration variable is removed.

* ``TransactionTestCase.assertQuerysetEqual()`` no longer calls ``repr()`` on a
  queryset when compared to string values.

* The ``django.core.cache.backends.memcached.MemcachedCache`` backend is
  removed.

* Support for the pre-Django 3.2 format of messages used by
  ``django.contrib.messages.storage.cookie.CookieStorage`` is removed.