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  1. ============================================
  2. Django 4.0 release notes - UNDER DEVELOPMENT
  3. ============================================
  4. *Expected December 2021*
  5. Welcome to Django 4.0!
  6. These release notes cover the :ref:`new features <whats-new-4.0>`, as well as
  7. some :ref:`backwards incompatible changes <backwards-incompatible-4.0>` you'll
  8. want to be aware of when upgrading from Django 3.2 or earlier. We've
  9. :ref:`begun the deprecation process for some features
  10. <deprecated-features-4.0>`.
  11. See the :doc:`/howto/upgrade-version` guide if you're updating an existing
  12. project.
  13. Python compatibility
  14. ====================
  15. Django 4.0 supports Python 3.8, 3.9, and 3.10. We **highly recommend** and only
  16. officially support the latest release of each series.
  17. The Django 3.2.x series is the last to support Python 3.6 and 3.7.
  18. .. _whats-new-4.0:
  19. What's new in Django 4.0
  20. ========================
  21. Functional unique constraints
  22. -----------------------------
  23. The new :attr:`*expressions <django.db.models.UniqueConstraint.expressions>`
  24. positional argument of
  25. :class:`UniqueConstraint() <django.db.models.UniqueConstraint>` enables
  26. creating functional unique constraints on expressions and database functions.
  27. For example::
  28. from django.db import models
  29. from django.db.models import UniqueConstraint
  30. from django.db.models.functions import Lower
  31. class MyModel(models.Model):
  32. first_name = models.CharField(max_length=255)
  33. last_name = models.CharField(max_length=255)
  34. class Meta:
  35. indexes = [
  36. UniqueConstraint(
  37. Lower('first_name'),
  38. Lower('last_name').desc(),
  39. name='first_last_name_unique',
  40. ),
  41. ]
  42. Functional unique constraints are added to models using the
  43. :attr:`Meta.constraints <django.db.models.Options.constraints>` option.
  44. ``scrypt`` password hasher
  45. --------------------------
  46. The new :ref:`scrypt password hasher <scrypt-usage>` is more secure and
  47. recommended over PBKDF2. However, it's not the default as it requires OpenSSL
  48. 1.1+ and more memory.
  49. Minor features
  50. --------------
  51. :mod:`django.contrib.admin`
  52. ~~~~~~~~~~~~~~~~~~~~~~~~~~~
  53. * The ``admin/base.html`` template now has a new block ``header`` which
  54. contains the admin site header.
  55. * The new :meth:`.ModelAdmin.get_formset_kwargs` method allows customizing the
  56. keyword arguments passed to the constructor of a formset.
  57. * The navigation sidebar now has a quick filter toolbar.
  58. * The new context variable ``model`` which contains the model class for each
  59. model is added to the :meth:`.AdminSite.each_context` method.
  60. * The new :attr:`.ModelAdmin.search_help_text` attribute allows specifying a
  61. descriptive text for the search box.
  62. * The :attr:`.InlineModelAdmin.verbose_name_plural` attribute now fallbacks to
  63. the :attr:`.InlineModelAdmin.verbose_name` + ``'s'``.
  64. :mod:`django.contrib.admindocs`
  65. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  66. * The admindocs now allows esoteric setups where :setting:`ROOT_URLCONF` is not
  67. a string.
  68. * The model section of the ``admindocs`` now shows cached properties.
  69. :mod:`django.contrib.auth`
  70. ~~~~~~~~~~~~~~~~~~~~~~~~~~
  71. * The default iteration count for the PBKDF2 password hasher is increased from
  72. 260,000 to 320,000.
  73. * The new
  74. :attr:`LoginView.next_page <django.contrib.auth.views.LoginView.next_page>`
  75. attribute and
  76. :meth:`~django.contrib.auth.views.LoginView.get_default_redirect_url` method
  77. allow customizing the redirect after login.
  78. :mod:`django.contrib.contenttypes`
  79. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  80. * ...
  81. :mod:`django.contrib.gis`
  82. ~~~~~~~~~~~~~~~~~~~~~~~~~
  83. * Added support for SpatiaLite 5.
  84. * :class:`~django.contrib.gis.gdal.GDALRaster` now allows creating rasters in
  85. any GDAL virtual filesystem.
  86. :mod:`django.contrib.messages`
  87. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  88. * ...
  89. :mod:`django.contrib.postgres`
  90. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  91. * The PostgreSQL backend now supports connecting by a service name. See
  92. :ref:`postgresql-connection-settings` for more details.
  93. * The new :class:`~django.contrib.postgres.operations.AddConstraintNotValid`
  94. operation allows creating check constraints on PostgreSQL without verifying
  95. that all existing rows satisfy the new constraint.
  96. * The new :class:`~django.contrib.postgres.operations.ValidateConstraint`
  97. operation allows validating check constraints which were created using
  98. :class:`~django.contrib.postgres.operations.AddConstraintNotValid` on
  99. PostgreSQL.
  100. * The new
  101. :class:`ArraySubquery() <django.contrib.postgres.expressions.ArraySubquery>`
  102. expression allows using subqueries to construct lists of values on
  103. PostgreSQL.
  104. :mod:`django.contrib.redirects`
  105. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  106. * ...
  107. :mod:`django.contrib.sessions`
  108. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  109. * ...
  110. :mod:`django.contrib.sitemaps`
  111. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  112. * ...
  113. :mod:`django.contrib.sites`
  114. ~~~~~~~~~~~~~~~~~~~~~~~~~~~
  115. * ...
  116. :mod:`django.contrib.staticfiles`
  117. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  118. * :class:`~django.contrib.staticfiles.storage.ManifestStaticFilesStorage` now
  119. replaces paths to JavaScript source map references with their hashed
  120. counterparts.
  121. * :class:`~django.contrib.staticfiles.storage.ManifestStaticFilesStorage` now
  122. replaces paths to JavaScript modules in ``import`` and ``export`` statements
  123. with their hashed counterparts.
  124. * The new ``manifest_storage`` argument of
  125. :class:`~django.contrib.staticfiles.storage.ManifestFilesMixin` and
  126. :class:`~django.contrib.staticfiles.storage.ManifestStaticFilesStorage`
  127. allows customizing the manifest file storage.
  128. :mod:`django.contrib.syndication`
  129. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  130. * ...
  131. Cache
  132. ~~~~~
  133. * The new async API for ``django.core.cache.backends.base.BaseCache`` begins
  134. the process of making cache backends async-compatible. The new async methods
  135. all have ``a`` prefixed names, e.g. ``aadd()``, ``aget()``, ``aset()``,
  136. ``aget_or_set()``, or ``adelete_many()``.
  137. Going forward, the ``a`` prefix will be used for async variants of methods
  138. generally.
  139. CSRF
  140. ~~~~
  141. * CSRF protection now consults the ``Origin`` header, if present. To facilitate
  142. this, :ref:`some changes <csrf-trusted-origins-changes-4.0>` to the
  143. :setting:`CSRF_TRUSTED_ORIGINS` setting are required.
  144. Decorators
  145. ~~~~~~~~~~
  146. * ...
  147. Email
  148. ~~~~~
  149. * ...
  150. Error Reporting
  151. ~~~~~~~~~~~~~~~
  152. * ...
  153. File Storage
  154. ~~~~~~~~~~~~
  155. * ...
  156. File Uploads
  157. ~~~~~~~~~~~~
  158. * ...
  159. Forms
  160. ~~~~~
  161. * :class:`~django.forms.ModelChoiceField` now includes the provided value in
  162. the ``params`` argument of a raised
  163. :exc:`~django.core.exceptions.ValidationError` for the ``invalid_choice``
  164. error message. This allows custom error messages to use the ``%(value)s``
  165. placeholder.
  166. * :class:`~django.forms.formsets.BaseFormSet` now renders non-form errors with
  167. an additional class of ``nonform`` to help distinguish them from
  168. form-specific errors.
  169. * :class:`~django.forms.formsets.BaseFormSet` now allows customizing the widget
  170. used when deleting forms via
  171. :attr:`~django.forms.formsets.BaseFormSet.can_delete` by setting the
  172. :attr:`~django.forms.formsets.BaseFormSet.deletion_widget` attribute or
  173. overriding :meth:`~django.forms.formsets.BaseFormSet.get_deletion_widget`
  174. method.
  175. Generic Views
  176. ~~~~~~~~~~~~~
  177. * :class:`~django.views.generic.edit.DeleteView` now uses
  178. :class:`~django.views.generic.edit.FormMixin`, allowing you to provide a
  179. :class:`~django.forms.Form` subclass, with a checkbox for example, to confirm
  180. deletion. In addition, this allows ``DeleteView`` to function with
  181. :class:`django.contrib.messages.views.SuccessMessageMixin`.
  182. Internationalization
  183. ~~~~~~~~~~~~~~~~~~~~
  184. * ...
  185. Logging
  186. ~~~~~~~
  187. * The alias of the database used in an SQL call is now passed as extra context
  188. along with each message to the :ref:`django-db-logger` logger.
  189. Management Commands
  190. ~~~~~~~~~~~~~~~~~~~
  191. * The :djadmin:`runserver` management command now supports the
  192. :option:`--skip-checks` option.
  193. * On PostgreSQL, :djadmin:`dbshell` now supports specifying a password file.
  194. * The :djadmin:`shell` command now respects :py:data:`sys.__interactivehook__`
  195. at startup. This allows loading shell history between interactive sessions.
  196. As a consequence, ``readline`` is no longer loaded if running in *isolated*
  197. mode.
  198. * The new :attr:`BaseCommand.suppressed_base_arguments
  199. <django.core.management.BaseCommand.suppressed_base_arguments>` attribute
  200. allows suppressing unsupported default command options in the help output.
  201. * The new :option:`startapp --exclude` and :option:`startproject --exclude`
  202. options allow excluding directories from the template.
  203. Migrations
  204. ~~~~~~~~~~
  205. * ...
  206. Models
  207. ~~~~~~
  208. * New :meth:`QuerySet.contains(obj) <.QuerySet.contains>` method returns
  209. whether the queryset contains the given object. This tries to perform the
  210. query in the simplest and fastest way possible.
  211. * The new ``precision`` argument of the
  212. :class:`Round() <django.db.models.functions.Round>` database function allows
  213. specifying the number of decimal places after rounding.
  214. * :meth:`.QuerySet.bulk_create` now sets the primary key on objects when using
  215. SQLite 3.35+.
  216. * :class:`~django.db.models.DurationField` now supports multiplying and
  217. dividing by scalar values on SQLite.
  218. * :meth:`.QuerySet.bulk_update` now returns the number of objects updated.
  219. * The new :attr:`.Aggregate.empty_aggregate_value` attribute allows specifying
  220. a value to return when the aggregation is used over an empty result set.
  221. * The ``skip_locked`` argument of :meth:`.QuerySet.select_for_update()` is now
  222. allowed on MariaDB 10.6+.
  223. * :class:`~django.db.models.Lookup` expressions may now be used in ``QuerySet``
  224. annotations, aggregations, and directly in filters.
  225. * The new :ref:`default <aggregate-default>` argument for built-in aggregates
  226. allows specifying a value to be returned when the queryset (or grouping)
  227. contains no entries, rather than ``None``.
  228. Requests and Responses
  229. ~~~~~~~~~~~~~~~~~~~~~~
  230. * The :class:`~django.middleware.security.SecurityMiddleware` now adds the
  231. :ref:`Cross-Origin Opener Policy <cross-origin-opener-policy>` header with a
  232. value of ``'same-origin'`` to prevent cross-origin popups from sharing the
  233. same browsing context. You can prevent this header from being added by
  234. setting the :setting:`SECURE_CROSS_ORIGIN_OPENER_POLICY` setting to ``None``.
  235. Security
  236. ~~~~~~~~
  237. * ...
  238. Serialization
  239. ~~~~~~~~~~~~~
  240. * ...
  241. Signals
  242. ~~~~~~~
  243. * The new ``stdout`` argument for :func:`~django.db.models.signals.pre_migrate`
  244. and :func:`~django.db.models.signals.post_migrate` signals allows redirecting
  245. output to a stream-like object. It should be preferred over
  246. :py:data:`sys.stdout` and :py:func:`print` when emitting verbose output in
  247. order to allow proper capture when testing.
  248. Templates
  249. ~~~~~~~~~
  250. * :tfilter:`floatformat` template filter now allows using the ``u`` suffix to
  251. force disabling localization.
  252. Tests
  253. ~~~~~
  254. * The new ``serialized_aliases`` argument of
  255. :func:`django.test.utils.setup_databases` determines which
  256. :setting:`DATABASES` aliases test databases should have their state
  257. serialized to allow usage of the
  258. :ref:`serialized_rollback <test-case-serialized-rollback>` feature.
  259. * Django test runner now supports a :option:`--buffer <test --buffer>` option
  260. with parallel tests.
  261. * The new ``logger`` argument to :class:`~django.test.runner.DiscoverRunner`
  262. allows a Python :py:ref:`logger <logger>` to be used for logging.
  263. * The new :meth:`.DiscoverRunner.log` method provides a way to log messages
  264. that uses the ``DiscoverRunner.logger``, or prints to the console if not set.
  265. * Django test runner now supports a :option:`--shuffle <test --shuffle>` option
  266. to execute tests in a random order.
  267. * The :option:`test --parallel` option now supports the value ``auto`` to run
  268. one test process for each processor core.
  269. * :meth:`.TestCase.captureOnCommitCallbacks` now captures new callbacks added
  270. while executing :func:`.transaction.on_commit` callbacks.
  271. URLs
  272. ~~~~
  273. * ...
  274. Utilities
  275. ~~~~~~~~~
  276. * ...
  277. Validators
  278. ~~~~~~~~~~
  279. * ...
  280. .. _backwards-incompatible-4.0:
  281. Backwards incompatible changes in 4.0
  282. =====================================
  283. Database backend API
  284. --------------------
  285. This section describes changes that may be needed in third-party database
  286. backends.
  287. * ``DatabaseOperations.year_lookup_bounds_for_date_field()`` and
  288. ``year_lookup_bounds_for_datetime_field()`` methods now take the optional
  289. ``iso_year`` argument in order to support bounds for ISO-8601 week-numbering
  290. years.
  291. * The second argument of ``DatabaseSchemaEditor._unique_sql()`` and
  292. ``_create_unique_sql()`` methods is now fields instead of columns.
  293. :mod:`django.contrib.gis`
  294. -------------------------
  295. * Support for PostGIS 2.3 is removed.
  296. * Support for GDAL 2.0 and GEOS 3.5 is removed.
  297. Dropped support for PostgreSQL 9.6
  298. ----------------------------------
  299. Upstream support for PostgreSQL 9.6 ends in November 2021. Django 4.0 supports
  300. PostgreSQL 10 and higher.
  301. Dropped support for Oracle 12.2 and 18c
  302. ---------------------------------------
  303. Upstream support for Oracle 12.2 ends in March 2022 and for Oracle 18c it ends
  304. in June 2021. Django 3.2 will be supported until April 2024. Django 4.0
  305. officially supports Oracle 19c.
  306. .. _csrf-trusted-origins-changes-4.0:
  307. ``CSRF_TRUSTED_ORIGINS`` changes
  308. --------------------------------
  309. Format change
  310. ~~~~~~~~~~~~~
  311. Values in the :setting:`CSRF_TRUSTED_ORIGINS` setting must include the scheme
  312. (e.g. ``'http://'`` or ``'https://'``) instead of only the hostname.
  313. Also, values that started with a dot, must now also include an asterisk before
  314. the dot. For example, change ``'.example.com'`` to ``'https://*.example.com'``.
  315. A system check detects any required changes.
  316. Configuring it may now be required
  317. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  318. As CSRF protection now consults the ``Origin`` header, you may need to set
  319. :setting:`CSRF_TRUSTED_ORIGINS`, particularly if you allow requests from
  320. subdomains by setting :setting:`CSRF_COOKIE_DOMAIN` (or
  321. :setting:`SESSION_COOKIE_DOMAIN` if :setting:`CSRF_USE_SESSIONS` is enabled) to
  322. a value starting with a dot.
  323. ``SecurityMiddleware`` no longer sets the ``X-XSS-Protection`` header
  324. ---------------------------------------------------------------------
  325. The :class:`~django.middleware.security.SecurityMiddleware` no longer sets the
  326. ``X-XSS-Protection`` header if the ``SECURE_BROWSER_XSS_FILTER`` setting is
  327. ``True``. The setting is removed.
  328. Most modern browsers don't honor the ``X-XSS-Protection`` HTTP header. You can
  329. use Content-Security-Policy_ without allowing ``'unsafe-inline'`` scripts
  330. instead.
  331. If you want to support legacy browsers and set the header, use this line in a
  332. custom middleware::
  333. response.headers.setdefault('X-XSS-Protection', '1; mode=block')
  334. .. _Content-Security-Policy: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
  335. Migrations autodetector changes
  336. -------------------------------
  337. The migrations autodetector now uses model states instead of model classes.
  338. Also, migration operations for ``ForeignKey`` and ``ManyToManyField`` fields no
  339. longer specify attributes which were not passed to the fields during
  340. initialization.
  341. As a side-effect, running ``makemigrations`` might generate no-op
  342. ``AlterField`` operations for ``ManyToManyField`` and ``ForeignKey`` fields in
  343. some cases.
  344. Miscellaneous
  345. -------------
  346. * Support for ``cx_Oracle`` < 7.0 is removed.
  347. * To allow serving a Django site on a subpath without changing the value of
  348. :setting:`STATIC_URL`, the leading slash is removed from that setting (now
  349. ``'static/'``) in the default :djadmin:`startproject` template.
  350. * The :class:`~django.contrib.admin.AdminSite` method for the admin ``index``
  351. view is no longer decorated with ``never_cache`` when accessed directly,
  352. rather than via the recommended ``AdminSite.urls`` property, or
  353. ``AdminSite.get_urls()`` method.
  354. * Unsupported operations on a sliced queryset now raise ``TypeError`` instead
  355. of ``AssertionError``.
  356. * The undocumented ``django.test.runner.reorder_suite()`` function is renamed
  357. to ``reorder_tests()``. It now accepts an iterable of tests rather than a
  358. test suite, and returns an iterator of tests.
  359. * Calling ``FileSystemStorage.delete()`` with an empty ``name`` now raises
  360. ``ValueError`` instead of ``AssertionError``.
  361. * Calling ``EmailMultiAlternatives.attach_alternative()`` or
  362. ``EmailMessage.attach()`` with an invalid ``content`` or ``mimetype``
  363. arguments now raise ``ValueError`` instead of ``AssertionError``.
  364. * :meth:`~django.test.SimpleTestCase.assertHTMLEqual` no longer considers a
  365. non-boolean attribute without a value equal to an attribute with the same
  366. name and value.
  367. * Tests that fail to load, for example due to syntax errors, now always match
  368. when using :option:`test --tag`.
  369. * The undocumented ``django.contrib.admin.utils.lookup_needs_distinct()``
  370. function is renamed to ``lookup_spawns_duplicates()``.
  371. * The undocumented ``HttpRequest.get_raw_uri()`` method is removed. The
  372. :meth:`.HttpRequest.build_absolute_uri` method may be a suitable alternative.
  373. * The ``object`` argument of undocumented ``ModelAdmin.log_addition()``,
  374. ``log_change()``, and ``log_deletion()`` methods is renamed to ``obj``.
  375. * :class:`~django.utils.feedgenerator.RssFeed`,
  376. :class:`~django.utils.feedgenerator.Atom1Feed`, and their subclasses now
  377. emit elements with no content as self-closing tags.
  378. * ``NodeList.render()`` no longer casts the output of ``render()`` method for
  379. individual nodes to a string. ``Node.render()`` should always return a string
  380. as documented.
  381. * The ``where_class`` property of ``django.db.models.sql.query.Query`` and the
  382. ``where_class`` argument to the private ``get_extra_restriction()`` method of
  383. ``ForeignObject`` and ``ForeignObjectRel`` are removed. If needed, initialize
  384. ``django.db.models.sql.where.WhereNode`` instead.
  385. * The ``filter_clause`` argument of the undocumented ``Query.add_filter()``
  386. method is replaced by two positional arguments ``filter_lhs`` and
  387. ``filter_rhs``.
  388. * :class:`~django.middleware.csrf.CsrfViewMiddleware` now uses
  389. ``request.META['CSRF_COOKIE_NEEDS_UPDATE']`` in place of
  390. ``request.META['CSRF_COOKIE_USED']``, ``request.csrf_cookie_needs_reset``,
  391. and ``response.csrf_cookie_set`` to track whether the CSRF cookie should be
  392. sent. This is an undocumented, private API.
  393. * The undocumented ``TRANSLATOR_COMMENT_MARK`` constant is moved from
  394. ``django.template.base`` to ``django.utils.translation.template``.
  395. * The ``real_apps`` argument of the undocumented
  396. ``django.db.migrations.state.ProjectState.__init__()`` method must now be a
  397. set if provided.
  398. * :class:`~django.forms.RadioSelect` and
  399. :class:`~django.forms.CheckboxSelectMultiple` widgets are now rendered in
  400. ``<div>`` tags so they are announced more concisely by screen readers. If you
  401. need the previous behavior, :ref:`override the widget template
  402. <overriding-built-in-widget-templates>` with the appropriate template from
  403. Django 3.2.
  404. * The :tfilter:`floatformat` template filter no longer depends on the
  405. ``USE_L10N`` setting and always returns localized output. Use the ``u``
  406. suffix to disable localization.
  407. * The default value of the ``USE_L10N`` setting is changed to ``True``. See the
  408. :ref:`Localization section <use_l10n_deprecation>` above for more details.
  409. .. _deprecated-features-4.0:
  410. Features deprecated in 4.0
  411. ==========================
  412. Time zone support
  413. -----------------
  414. In order to follow good practice, the default value of the :setting:`USE_TZ`
  415. setting will change from ``False`` to ``True``, and time zone support will be
  416. enabled by default, in Django 5.0.
  417. Note that the default :file:`settings.py` file created by
  418. :djadmin:`django-admin startproject <startproject>` includes
  419. :setting:`USE_TZ = True <USE_TZ>` since Django 1.4.
  420. You can set ``USE_TZ`` to ``False`` in your project settings before then to
  421. opt-out.
  422. .. _use_l10n_deprecation:
  423. Localization
  424. ------------
  425. In order to follow good practice, the default value of the ``USE_L10N`` setting
  426. is changed from ``False`` to ``True``.
  427. Moreover ``USE_L10N`` is deprecated as of this release. Starting with Django
  428. 5.0, by default, any date or number displayed by Django will be localized.
  429. The :ttag:`{% localize %} <localize>` tag and the :tfilter:`localize`/
  430. :tfilter:`unlocalize` filters will still be honored by Django.
  431. Miscellaneous
  432. -------------
  433. * ``SERIALIZE`` test setting is deprecated as it can be inferred from the
  434. :attr:`~django.test.TestCase.databases` with the
  435. :ref:`serialized_rollback <test-case-serialized-rollback>` option enabled.
  436. * The undocumented ``django.utils.baseconv`` module is deprecated.
  437. * The undocumented ``django.utils.datetime_safe`` module is deprecated.
  438. * The default sitemap protocol for sitemaps built outside the context of a
  439. request will change from ``'http'`` to ``'https'`` in Django 5.0.
  440. * The ``extra_tests`` argument for :meth:`.DiscoverRunner.build_suite` and
  441. :meth:`.DiscoverRunner.run_tests` is deprecated.
  442. * The :class:`~django.contrib.postgres.aggregates.ArrayAgg`,
  443. :class:`~django.contrib.postgres.aggregates.JSONBAgg`, and
  444. :class:`~django.contrib.postgres.aggregates.StringAgg` aggregates will return
  445. ``None`` when there are no rows instead of ``[]``, ``[]``, and ``''``
  446. respectively in Django 5.0. If you need the previous behavior, explicitly set
  447. ``default`` to ``Value([])``, ``Value('[]')``, or ``Value('')``.
  448. Features removed in 4.0
  449. =======================
  450. These features have reached the end of their deprecation cycle and are removed
  451. in Django 4.0.
  452. See :ref:`deprecated-features-3.0` for details on these changes, including how
  453. to remove usage of these features.
  454. * ``django.utils.http.urlquote()``, ``urlquote_plus()``, ``urlunquote()``, and
  455. ``urlunquote_plus()`` are removed.
  456. * ``django.utils.encoding.force_text()`` and ``smart_text()`` are removed.
  457. * ``django.utils.translation.ugettext()``, ``ugettext_lazy()``,
  458. ``ugettext_noop()``, ``ungettext()``, and ``ungettext_lazy()`` are removed.
  459. * ``django.views.i18n.set_language()`` doesn't set the user language in
  460. ``request.session`` (key ``_language``).
  461. * ``alias=None`` is required in the signature of
  462. ``django.db.models.Expression.get_group_by_cols()`` subclasses.
  463. * ``django.utils.text.unescape_entities()`` is removed.
  464. * ``django.utils.http.is_safe_url()`` is removed.
  465. See :ref:`deprecated-features-3.1` for details on these changes, including how
  466. to remove usage of these features.
  467. * The ``PASSWORD_RESET_TIMEOUT_DAYS`` setting is removed.
  468. * The :lookup:`isnull` lookup no longer allows using non-boolean values as the
  469. right-hand side.
  470. * The ``django.db.models.query_utils.InvalidQuery`` exception class is removed.
  471. * The ``django-admin.py`` entry point is removed.
  472. * The ``HttpRequest.is_ajax()`` method is removed.
  473. * Support for the pre-Django 3.1 encoding format of cookies values used by
  474. ``django.contrib.messages.storage.cookie.CookieStorage`` is removed.
  475. * Support for the pre-Django 3.1 password reset tokens in the admin site (that
  476. use the SHA-1 hashing algorithm) is removed.
  477. * Support for the pre-Django 3.1 encoding format of sessions is removed.
  478. * Support for the pre-Django 3.1 ``django.core.signing.Signer`` signatures
  479. (encoded with the SHA-1 algorithm) is removed.
  480. * Support for the pre-Django 3.1 ``django.core.signing.dumps()`` signatures
  481. (encoded with the SHA-1 algorithm) in ``django.core.signing.loads()`` is
  482. removed.
  483. * Support for the pre-Django 3.1 user sessions (that use the SHA-1 algorithm)
  484. is removed.
  485. * The ``get_response`` argument for
  486. ``django.utils.deprecation.MiddlewareMixin.__init__()`` is required and
  487. doesn't accept ``None``.
  488. * The ``providing_args`` argument for ``django.dispatch.Signal`` is removed.
  489. * The ``length`` argument for ``django.utils.crypto.get_random_string()`` is
  490. required.
  491. * The ``list`` message for ``ModelMultipleChoiceField`` is removed.
  492. * Support for passing raw column aliases to ``QuerySet.order_by()`` is removed.
  493. * The ``NullBooleanField`` model field is removed, except for support in
  494. historical migrations.
  495. * ``django.conf.urls.url()`` is removed.
  496. * The ``django.contrib.postgres.fields.JSONField`` model field is removed,
  497. except for support in historical migrations.
  498. * ``django.contrib.postgres.fields.jsonb.KeyTransform`` and
  499. ``django.contrib.postgres.fields.jsonb.KeyTextTransform`` are removed.
  500. * ``django.contrib.postgres.forms.JSONField`` is removed.
  501. * The ``{% ifequal %}`` and ``{% ifnotequal %}`` template tags are removed.
  502. * The ``DEFAULT_HASHING_ALGORITHM`` transitional setting is removed.