533 lines
15 KiB
Plaintext
533 lines
15 KiB
Plaintext
============================================
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Django 4.0 release notes - UNDER DEVELOPMENT
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============================================
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*Expected December 2021*
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Welcome to Django 4.0!
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These release notes cover the :ref:`new features <whats-new-4.0>`, as well as
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some :ref:`backwards incompatible changes <backwards-incompatible-4.0>` you'll
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want to be aware of when upgrading from Django 3.2 or earlier. We've
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:ref:`begun the deprecation process for some features
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<deprecated-features-4.0>`.
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See the :doc:`/howto/upgrade-version` guide if you're updating an existing
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project.
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Python compatibility
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====================
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Django 4.0 supports Python 3.8, 3.9, and 3.10. We **highly recommend** and only
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officially support the latest release of each series.
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The Django 3.2.x series is the last to support Python 3.6 and 3.7.
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.. _whats-new-4.0:
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What's new in Django 4.0
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========================
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Functional unique constraints
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-----------------------------
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The new :attr:`*expressions <django.db.models.UniqueConstraint.expressions>`
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positional argument of
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:class:`UniqueConstraint() <django.db.models.UniqueConstraint>` enables
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creating functional unique constraints on expressions and database functions.
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For example::
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from django.db import models
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from django.db.models import UniqueConstraint
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from django.db.models.functions import Lower
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class MyModel(models.Model):
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first_name = models.CharField(max_length=255)
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last_name = models.CharField(max_length=255)
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class Meta:
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indexes = [
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UniqueConstraint(
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Lower('first_name'),
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Lower('last_name').desc(),
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name='first_last_name_unique',
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),
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]
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Functional unique constraints are added to models using the
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:attr:`Meta.constraints <django.db.models.Options.constraints>` option.
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Minor features
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--------------
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:mod:`django.contrib.admin`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* The ``admin/base.html`` template now has a new block ``header`` which
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contains the admin site header.
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* The new :meth:`.ModelAdmin.get_formset_kwargs` method allows customizing the
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keyword arguments passed to the constructor of a formset.
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* The navigation sidebar now has a quick filter toolbar.
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* The new context variable ``model`` which contains the model class for each
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model is added to the :meth:`.AdminSite.each_context` method.
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:mod:`django.contrib.admindocs`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* The admindocs now allows esoteric setups where :setting:`ROOT_URLCONF` is not
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a string.
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* The model section of the ``admindocs`` now shows cached properties.
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:mod:`django.contrib.auth`
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~~~~~~~~~~~~~~~~~~~~~~~~~~
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* The default iteration count for the PBKDF2 password hasher is increased from
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260,000 to 320,000.
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* The new
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:attr:`LoginView.next_page <django.contrib.auth.views.LoginView.next_page>`
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attribute and
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:meth:`~django.contrib.auth.views.LoginView.get_default_redirect_url` method
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allow customizing the redirect after login.
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:mod:`django.contrib.contenttypes`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* ...
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:mod:`django.contrib.gis`
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~~~~~~~~~~~~~~~~~~~~~~~~~
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* Added support for SpatiaLite 5.
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* :class:`~django.contrib.gis.gdal.GDALRaster` now allows creating rasters in
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any GDAL virtual filesystem.
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:mod:`django.contrib.messages`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* ...
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:mod:`django.contrib.postgres`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* The PostgreSQL backend now supports connecting by a service name. See
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:ref:`postgresql-connection-settings` for more details.
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:mod:`django.contrib.redirects`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* ...
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:mod:`django.contrib.sessions`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* ...
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:mod:`django.contrib.sitemaps`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* ...
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:mod:`django.contrib.sites`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* ...
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:mod:`django.contrib.staticfiles`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* :class:`~django.contrib.staticfiles.storage.ManifestStaticFilesStorage` now
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replaces paths to JavaScript source map references with their hashed
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counterparts.
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:mod:`django.contrib.syndication`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* ...
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Cache
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~~~~~
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* ...
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CSRF
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~~~~
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* CSRF protection now consults the ``Origin`` header, if present. To facilitate
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this, :ref:`some changes <csrf-trusted-origins-changes-4.0>` to the
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:setting:`CSRF_TRUSTED_ORIGINS` setting are required.
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Decorators
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~~~~~~~~~~
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* ...
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Email
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~~~~~
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* ...
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Error Reporting
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~~~~~~~~~~~~~~~
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* ...
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File Storage
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~~~~~~~~~~~~
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* ...
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File Uploads
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~~~~~~~~~~~~
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* ...
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Forms
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~~~~~
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* :class:`~django.forms.ModelChoiceField` now includes the provided value in
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the ``params`` argument of a raised
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:exc:`~django.core.exceptions.ValidationError` for the ``invalid_choice``
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error message. This allows custom error messages to use the ``%(value)s``
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placeholder.
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Generic Views
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~~~~~~~~~~~~~
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* ...
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Internationalization
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~~~~~~~~~~~~~~~~~~~~
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* ...
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Logging
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~~~~~~~
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* ...
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Management Commands
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~~~~~~~~~~~~~~~~~~~
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* The :djadmin:`runserver` management command now supports the
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:option:`--skip-checks` option.
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* On PostgreSQL, :djadmin:`dbshell` now supports specifying a password file.
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Migrations
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~~~~~~~~~~
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* ...
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Models
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~~~~~~
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* New :meth:`QuerySet.contains(obj) <.QuerySet.contains>` method returns
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whether the queryset contains the given object. This tries to perform the
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query in the simplest and fastest way possible.
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* The new ``precision`` argument of the
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:class:`Round() <django.db.models.functions.Round>` database function allows
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specifying the number of decimal places after rounding.
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* :meth:`.QuerySet.bulk_create` now sets the primary key on objects when using
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SQLite 3.35+.
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* :class:`~django.db.models.DurationField` now supports multiplying and
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dividing by scalar values on SQLite.
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Requests and Responses
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~~~~~~~~~~~~~~~~~~~~~~
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* The :class:`~django.middleware.security.SecurityMiddleware` now adds the
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:ref:`Cross-Origin Opener Policy <cross-origin-opener-policy>` header with a
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value of ``'same-origin'`` to prevent cross-origin popups from sharing the
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same browsing context. You can prevent this header from being added by
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setting the :setting:`SECURE_CROSS_ORIGIN_OPENER_POLICY` setting to ``None``.
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Security
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~~~~~~~~
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* ...
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Serialization
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~~~~~~~~~~~~~
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* ...
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Signals
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~~~~~~~
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* The new ``stdout`` argument for :func:`~django.db.models.signals.pre_migrate`
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and :func:`~django.db.models.signals.post_migrate` signals allows redirecting
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output to a stream-like object. It should be preferred over
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:py:data:`sys.stdout` and :py:func:`print` when emitting verbose output in
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order to allow proper capture when testing.
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Templates
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~~~~~~~~~
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* ...
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Tests
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~~~~~
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* The new ``serialized_aliases`` argument of
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:func:`django.test.utils.setup_databases` determines which
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:setting:`DATABASES` aliases test databases should have their state
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serialized to allow usage of the
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:ref:`serialized_rollback <test-case-serialized-rollback>` feature.
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* Django test runner now supports a :option:`--buffer <test --buffer>` option
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with parallel tests.
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URLs
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~~~~
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* ...
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Utilities
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~~~~~~~~~
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* ...
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Validators
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~~~~~~~~~~
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* ...
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.. _backwards-incompatible-4.0:
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Backwards incompatible changes in 4.0
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=====================================
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Database backend API
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--------------------
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This section describes changes that may be needed in third-party database
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backends.
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* ``DatabaseOperations.year_lookup_bounds_for_date_field()`` and
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``year_lookup_bounds_for_datetime_field()`` methods now take the optional
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``iso_year`` argument in order to support bounds for ISO-8601 week-numbering
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years.
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:mod:`django.contrib.gis`
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-------------------------
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* Support for PostGIS 2.3 is removed.
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* Support for GDAL 2.0 and GEOS 3.5 is removed.
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Dropped support for PostgreSQL 9.6
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----------------------------------
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Upstream support for PostgreSQL 9.6 ends in November 2021. Django 4.0 supports
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PostgreSQL 10 and higher.
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Dropped support for Oracle 12.2 and 18c
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---------------------------------------
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Upstream support for Oracle 12.2 ends in March 2022 and for Oracle 18c it ends
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in June 2021. Django 3.2 will be supported until April 2024. Django 4.0
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officially supports Oracle 19c.
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.. _csrf-trusted-origins-changes-4.0:
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``CSRF_TRUSTED_ORIGINS`` changes
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--------------------------------
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Format change
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~~~~~~~~~~~~~
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Values in the :setting:`CSRF_TRUSTED_ORIGINS` setting must include the scheme
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(e.g. ``'http://'`` or ``'https://'``) instead of only the hostname.
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Also, values that started with a dot, must now also include an asterisk before
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the dot. For example, change ``'.example.com'`` to ``'https://*.example.com'``.
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A system check detects any required changes.
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Configuring it may now be required
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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As CSRF protection now consults the ``Origin`` header, you may need to set
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:setting:`CSRF_TRUSTED_ORIGINS`, particularly if you allow requests from
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subdomains by setting :setting:`CSRF_COOKIE_DOMAIN` (or
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:setting:`SESSION_COOKIE_DOMAIN` if :setting:`CSRF_USE_SESSIONS` is enabled) to
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a value starting with a dot.
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``SecurityMiddleware`` no longer sets the ``X-XSS-Protection`` header
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---------------------------------------------------------------------
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The :class:`~django.middleware.security.SecurityMiddleware` no longer sets the
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``X-XSS-Protection`` header if the ``SECURE_BROWSER_XSS_FILTER`` setting is
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``True``. The setting is removed.
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Most modern browsers don't honor the ``X-XSS-Protection`` HTTP header. You can
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use Content-Security-Policy_ without allowing ``'unsafe-inline'`` scripts
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instead.
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If you want to support legacy browsers and set the header, use this line in a
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custom middleware::
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response.headers.setdefault('X-XSS-Protection', '1; mode=block')
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.. _Content-Security-Policy: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
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Miscellaneous
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-------------
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* Support for ``cx_Oracle`` < 7.0 is removed.
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* To allow serving a Django site on a subpath without changing the value of
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:setting:`STATIC_URL`, the leading slash is removed from that setting (now
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``'static/'``) in the default :djadmin:`startproject` template.
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* The :class:`~django.contrib.admin.AdminSite` method for the admin ``index``
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view is no longer decorated with ``never_cache`` when accessed directly,
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rather than via the recommended ``AdminSite.urls`` property, or
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``AdminSite.get_urls()`` method.
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* Unsupported operations on a sliced queryset now raise ``TypeError`` instead
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of ``AssertionError``.
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* The undocumented ``django.test.runner.reorder_suite()`` function is renamed
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to ``reorder_tests()``. It now accepts an iterable of tests rather than a
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test suite, and returns an iterator of tests.
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* Calling ``FileSystemStorage.delete()`` with an empty ``name`` now raises
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``ValueError`` instead of ``AssertionError``.
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* Calling ``EmailMultiAlternatives.attach_alternative()`` or
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``EmailMessage.attach()`` with an invalid ``content`` or ``mimetype``
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arguments now raise ``ValueError`` instead of ``AssertionError``.
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* :meth:`~django.test.SimpleTestCase.assertHTMLEqual` no longer considers a
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non-boolean attribute without a value equal to an attribute with the same
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name and value.
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* Tests that fail to load, for example due to syntax errors, now always match
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when using :option:`test --tag`.
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* The migrations autodetector now uses model states instead of model classes.
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As a side-effect ``makemigrations`` might generate no-op ``AlterField``
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operations for ``ForeignKey`` fields in some cases.
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* The undocumented ``django.contrib.admin.utils.lookup_needs_distinct()``
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function is renamed to ``lookup_spawns_duplicates()``.
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* The undocumented ``HttpRequest.get_raw_uri()`` method is removed. The
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:meth:`.HttpRequest.build_absolute_uri` method may be a suitable alternative.
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.. _deprecated-features-4.0:
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Features deprecated in 4.0
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==========================
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Miscellaneous
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-------------
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* ``SERIALIZE`` test setting is deprecated as it can be inferred from the
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:attr:`~django.test.TestCase.databases` with the
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:ref:`serialized_rollback <test-case-serialized-rollback>` option enabled.
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* The undocumented ``django.utils.baseconv`` module is deprecated.
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* The undocumented ``django.utils.datetime_safe`` module is deprecated.
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Features removed in 4.0
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=======================
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These features have reached the end of their deprecation cycle and are removed
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in Django 4.0.
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See :ref:`deprecated-features-3.0` for details on these changes, including how
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to remove usage of these features.
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* ``django.utils.http.urlquote()``, ``urlquote_plus()``, ``urlunquote()``, and
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``urlunquote_plus()`` are removed.
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* ``django.utils.encoding.force_text()`` and ``smart_text()`` are removed.
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* ``django.utils.translation.ugettext()``, ``ugettext_lazy()``,
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``ugettext_noop()``, ``ungettext()``, and ``ungettext_lazy()`` are removed.
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* ``django.views.i18n.set_language()`` doesn't set the user language in
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``request.session`` (key ``_language``).
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* ``alias=None`` is required in the signature of
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``django.db.models.Expression.get_group_by_cols()`` subclasses.
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* ``django.utils.text.unescape_entities()`` is removed.
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* ``django.utils.http.is_safe_url()`` is removed.
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See :ref:`deprecated-features-3.1` for details on these changes, including how
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to remove usage of these features.
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* The ``PASSWORD_RESET_TIMEOUT_DAYS`` setting is removed.
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* The :lookup:`isnull` lookup no longer allows using non-boolean values as the
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right-hand side.
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* The ``django.db.models.query_utils.InvalidQuery`` exception class is removed.
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* The ``django-admin.py`` entry point is removed.
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* The ``HttpRequest.is_ajax()`` method is removed.
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* Support for the pre-Django 3.1 encoding format of cookies values used by
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``django.contrib.messages.storage.cookie.CookieStorage`` is removed.
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* Support for the pre-Django 3.1 password reset tokens in the admin site (that
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use the SHA-1 hashing algorithm) is removed.
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* Support for the pre-Django 3.1 encoding format of sessions is removed.
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* Support for the pre-Django 3.1 ``django.core.signing.Signer`` signatures
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(encoded with the SHA-1 algorithm) is removed.
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* Support for the pre-Django 3.1 ``django.core.signing.dumps()`` signatures
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(encoded with the SHA-1 algorithm) in ``django.core.signing.loads()`` is
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removed.
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* Support for the pre-Django 3.1 user sessions (that use the SHA-1 algorithm)
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is removed.
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* The ``get_request`` argument for
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``django.utils.deprecation.MiddlewareMixin.__init__()`` is required and
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doesn't accept ``None``.
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* The ``providing_args`` argument for ``django.dispatch.Signal`` is removed.
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* The ``length`` argument for ``django.utils.crypto.get_random_string()`` is
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required.
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* The ``list`` message for ``ModelMultipleChoiceField`` is removed.
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* Support for passing raw column aliases to ``QuerySet.order_by()`` is removed.
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* The ``NullBooleanField`` model field is removed, except for support in
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historical migrations.
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* ``django.conf.urls.url()`` is removed.
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* The ``django.contrib.postgres.fields.JSONField`` model field is removed,
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except for support in historical migrations.
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* ``django.contrib.postgres.fields.jsonb.KeyTransform`` and
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``django.contrib.postgres.fields.jsonb.KeyTextTransform`` are removed.
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* ``django.contrib.postgres.forms.JSONField`` is removed.
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* The ``{% ifequal %}`` and ``{% ifnotequal %}`` template tags are removed.
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* The ``DEFAULT_HASHING_ALGORITHM`` transitional setting is removed.
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