# Documentazione Django 6.0.7

# Note di rilascio di Django 3.1

4 Agosto 2020

Welcome to Django 3.1!

These release notes cover the new features, as well as some backwards incompatible changes you’ll want to be aware of when upgrading from Django 3.0 or earlier. We’ve dropped some features that have reached the end of their deprecation cycle, and we’ve begun the deprecation process for some features.

See the Come aggiornare Django ad una nuova versione guide if you’re updating an existing project.

## Compatibilità con Python

Django 3.1 supports Python 3.6, 3.7, 3.8, and 3.9 (as of 3.1.3). We highly recommend and only officially support the latest release of each series.

## What’s new in Django 3.1

### Asynchronous views and middleware support

Django now supports a fully asynchronous request path, including:

- Asynchronous views

- Asynchronous middleware

- Asynchronous tests and test client

To get started with async views, you need to declare a view using `async def`:

    async def my_view(request):
        await asyncio.sleep(0.5)
        return HttpResponse("Hello, async world!")

All asynchronous features are supported whether you are running under WSGI or ASGI mode. However, there will be performance penalties using async code in WSGI mode. You can read more about the specifics in Asynchronous support documentation.

You are free to mix async and sync views, middleware, and tests as much as you want. Django will ensure that you always end up with the right execution context. We expect most projects will keep the majority of their views synchronous, and only have a select few running in async mode - but it is entirely your choice.

Django’s ORM, cache layer, and other pieces of code that do long-running network calls do not yet support async access. We expect to add support for them in upcoming releases. Async views are ideal, however, if you are doing a lot of API or HTTP calls inside your view, you can now natively do all those HTTP calls in parallel to considerably speed up your view’s execution.

Asynchronous support should be entirely backwards-compatible and we have tried to ensure that it has no speed regressions for your existing, synchronous code. It should have no noticeable effect on any existing Django projects.

### JSONField for all supported database backends

Django now includes `models.JSONField` and `forms.JSONField` that can be used on all supported database backends. Both fields support the use of custom JSON encoders and decoders. The model field supports the introspection, lookups, and transforms that were previously PostgreSQL-only:

    from django.db import models

    class ContactInfo(models.Model):
        data = models.JSONField()

    ContactInfo.objects.create(
        data={
            "name": "John",
            "cities": ["London", "Cambridge"],
            "pets": {"dogs": ["Rufus", "Meg"]},
        }
    )
    ContactInfo.objects.filter(
        data__name="John",
        data__pets__has_key="dogs",
        data__cities__contains="London",
    ).delete()

If your project uses `django.contrib.postgres.fields.JSONField`, plus the related form field and transforms, you should adjust to use the new fields, and generate and apply a database migration. For now, the old fields and transforms are left as a reference to the new ones and are deprecated as of this release.

### `DEFAULT_HASHING_ALGORITHM` settings

The new `DEFAULT_HASHING_ALGORITHM` transitional setting allows specifying the default hashing algorithm to use for encoding cookies, password reset tokens in the admin site, user sessions, and signatures created by `django.core.signing.Signer` and `django.core.signing.dumps()`.

Support for SHA-256 was added in Django 3.1. If you are upgrading multiple instances of the same project to Django 3.1, you should set `DEFAULT_HASHING_ALGORITHM` to `'sha1'` during the transition, in order to allow compatibility with the older versions of Django. Note that this requires Django 3.1.1+. Once the transition to 3.1 is complete you can stop overriding `DEFAULT_HASHING_ALGORITHM`.

This setting is deprecated as of this release, because support for tokens, cookies, sessions, and signatures that use SHA-1 algorithm will be removed in Django 4.0.

### Minor features

#### `django.contrib.admin`

- The new `django.contrib.admin.EmptyFieldListFilter` for `ModelAdmin.list_filter` allows filtering on empty values (empty strings and nulls) in the admin changelist view.

- Filters in the right sidebar of the admin changelist view now contain a link to clear all filters.

- The admin now has a sidebar on larger screens for easier navigation. It is enabled by default but can be disabled by using a custom `AdminSite` and setting `AdminSite.enable_nav_sidebar` to `False`.

  Rendering the sidebar requires access to the current request in order to set CSS and ARIA role affordances. This requires using `'django.template.context_processors.request'` in the `'context_processors'` option of `OPTIONS`.

- Initially empty `extra` inlines can now be removed, in the same way as dynamically created ones.

- `XRegExp` is upgraded from version 2.0.0 to 3.2.0.

- jQuery is upgraded from version 3.4.1 to 3.5.1.

- Select2 library is upgraded from version 4.0.7 to 4.0.13.

#### `django.contrib.auth`

- The default iteration count for the PBKDF2 password hasher is increased from 180,000 to 216,000.

- The new `PASSWORD_RESET_TIMEOUT` setting allows defining the number of seconds a password reset link is valid for. This is encouraged instead of the deprecated `PASSWORD_RESET_TIMEOUT_DAYS` setting, which will be removed in Django 4.0.

- The password reset mechanism now uses the SHA-256 hashing algorithm. Support for tokens that use the old hashing algorithm remains until Django 4.0.

- `AbstractBaseUser.get_session_auth_hash()` now uses the SHA-256 hashing algorithm. Support for user sessions that use the old hashing algorithm remains until Django 4.0.

#### `django.contrib.contenttypes`

- The new `remove_stale_contenttypes --include-stale-apps` option allows removing stale content types from previously installed apps that have been removed from `INSTALLED_APPS`.

#### `django.contrib.gis`

- `relate` lookup is now supported on MariaDB.

- Added the `LinearRing.is_counterclockwise` property.

- `AsGeoJSON` is now supported on Oracle.

- Added the `AsWKB` and `AsWKT` functions.

- Added support for PostGIS 3 and GDAL 3.

#### `django.contrib.humanize`

- `intword` template filter now supports negative integers.

#### `django.contrib.postgres`

- The new `BloomIndex` class allows creating `bloom` indexes in the database. The new `BloomExtension` migration operation installs the `bloom` extension to add support for this index.

- `get_FOO_display()` now supports `ArrayField` and `RangeField`.

- The new `rangefield.lower_inc`, `rangefield.lower_inf`, `rangefield.upper_inc`, and `rangefield.upper_inf` lookups allow querying `RangeField` by a bound type.

- `rangefield.contained_by` now supports `SmallAutoField`, `AutoField`, `BigAutoField`, `SmallIntegerField`, and `DecimalField`.

- `SearchQuery` now supports `'websearch'` search type on PostgreSQL 11+.

- `SearchQuery.value` now supports query expressions.

- The new `SearchHeadline` class allows highlighting search results.

- `search` lookup now supports query expressions.

- The new `cover_density` parameter of `SearchRank` allows ranking by cover density.

- The new `normalization` parameter of `SearchRank` allows rank normalization.

- The new `ExclusionConstraint.deferrable` attribute allows creating deferrable exclusion constraints.

#### `django.contrib.sessions`

- The `SESSION_COOKIE_SAMESITE` setting now allows `'None'` (string) value to explicitly state that the cookie is sent with all same-site and cross-site requests.

#### `django.contrib.staticfiles`

- The `STATICFILES_DIRS` setting now supports `pathlib.Path`.

#### Cache

- The `cache_control()` decorator and `patch_cache_control()` method now support multiple field names in the `no-cache` directive for the `Cache-Control` header, according to RFC 7234 Section 5.2.2.2.

- `delete()` now returns `True` if the key was successfully deleted, `False` otherwise.

#### CSRF

- The `CSRF_COOKIE_SAMESITE` setting now allows `'None'` (string) value to explicitly state that the cookie is sent with all same-site and cross-site requests.

#### Email

- The `EMAIL_FILE_PATH` setting, used by the file email backend, now supports `pathlib.Path`.

#### Error Reporting

- `django.views.debug.SafeExceptionReporterFilter` now filters sensitive values from `request.META` in exception reports.

- The new `SafeExceptionReporterFilter.cleansed_substitute` and `SafeExceptionReporterFilter.hidden_settings` attributes allow customization of sensitive settings and `request.META` filtering in exception reports.

- The technical 404 debug view now respects `DEFAULT_EXCEPTION_REPORTER_FILTER` when applying settings filtering.

- The new `DEFAULT_EXCEPTION_REPORTER` allows providing a `django.views.debug.ExceptionReporter` subclass to customize exception report generation. See Rapporti di errore personalizzati for details.

#### File Storage

- `FileSystemStorage.save()` method now supports `pathlib.Path`.

- `FileField` and `ImageField` now accept a callable for `storage`. This allows you to modify the used storage at runtime, selecting different storages for different environments, for example.

#### I Form

- `ModelChoiceIterator`, used by `ModelChoiceField` and `ModelMultipleChoiceField`, now uses `ModelChoiceIteratorValue` that can be used by widgets to access model instances. See Iterating relationship choices for details.

- `django.forms.DateTimeField` now accepts dates in a subset of ISO 8601 datetime formats, including optional timezone, e.g. `2019-10-10T06:47`, `2019-10-10T06:47:23+04:00`, or `2019-10-10T06:47:23Z`. The timezone will always be retained if provided, with timezone-aware datetimes being returned even when `USE_TZ` is `False`.

  Additionally, `DateTimeField` now uses `DATE_INPUT_FORMATS` in addition to `DATETIME_INPUT_FORMATS` when converting a field input to a `datetime` value.

- `MultiWidget.widgets` now accepts a dictionary which allows customizing subwidget `name` attributes.

- The new `BoundField.widget_type` property can be used to dynamically adjust form rendering based upon the widget type.

#### Internationalization

- The `LANGUAGE_COOKIE_SAMESITE` setting now allows `'None'` (string) value to explicitly state that the cookie is sent with all same-site and cross-site requests.

- Added support and translations for the Algerian Arabic, Igbo, Kyrgyz, Tajik, and Turkmen languages.

#### Management Commands

- The new `check --database` option allows specifying database aliases for running the `database` system checks. Previously these checks were enabled for all configured `DATABASES` by passing the `database` tag to the command.

- The new `migrate --check` option makes the command exit with a non-zero status when unapplied migrations are detected.

- The new `returncode` argument for `CommandError` allows customizing the exit status for management commands.

- The new `dbshell -- ARGUMENTS` option allows passing extra arguments to the command-line client for the database.

- The `flush` and `sqlflush` commands now include SQL to reset sequences on SQLite.

#### Modelli

- The new `ExtractIsoWeekDay` function extracts ISO-8601 week days from `DateField` and `DateTimeField`, and the new `iso_week_day` lookup allows querying by an ISO-8601 day of week.

- `QuerySet.explain()` now supports:

  - `TREE` format on MySQL 8.0.16+,

  - `analyze` option on MySQL 8.0.18+ and MariaDB.

- Added `PositiveBigIntegerField` which acts much like a `PositiveIntegerField` except that it only allows values under a certain (database-dependent) limit. Values from `0` to `9223372036854775807` are safe in all databases supported by Django.

- The new `RESTRICT` option for `on_delete` argument of `ForeignKey` and `OneToOneField` emulates the behavior of the SQL constraint `ON DELETE RESTRICT`.

- `CheckConstraint.check` now supports boolean expressions.

- The `RelatedManager.add()`, `create()`, and `set()` methods now accept callables as values in the `through_defaults` argument.

- The new `is_dst` parameter of the `QuerySet.datetimes()` determines the treatment of nonexistent and ambiguous datetimes.

- The new `F` expression `bitxor()` method allows bitwise XOR operation.

- `QuerySet.bulk_create()` now sets the primary key on objects when using MariaDB 10.5+.

- The `DatabaseOperations.sql_flush()` method now generates more efficient SQL on MySQL by using `DELETE` instead of `TRUNCATE` statements for tables which don’t require resetting sequences.

- SQLite functions are now marked as `deterministic` on Python 3.8+. This allows using them in check constraints and partial indexes.

- The new `UniqueConstraint.deferrable` attribute allows creating deferrable unique constraints.

#### Pagination

- `Paginator` can now be iterated over to yield its pages.

#### Requests and Responses

- If `ALLOWED_HOSTS` is empty and `DEBUG=True`, subdomains of localhost are now allowed in the `Host` header, e.g. `static.localhost`.

- `HttpResponse.set_cookie()` and `HttpResponse.set_signed_cookie()` now allow using `samesite='None'` (string) to explicitly state that the cookie is sent with all same-site and cross-site requests.

- The new `HttpRequest.accepts()` method returns whether the request accepts the given MIME type according to the `Accept` HTTP header.

#### Sicurezza

- The `SECURE_REFERRER_POLICY` setting now defaults to `'same-origin'`. With this configured, `SecurityMiddleware` sets the Referrer Policy header to `same-origin` on all responses that do not already have it. This prevents the `Referer` header being sent to other origins. If you need the previous behavior, explicitly set `SECURE_REFERRER_POLICY` to `None`.

- The default algorithm of `django.core.signing.Signer`, `django.core.signing.loads()`, and `django.core.signing.dumps()` is changed to the SHA-256. Support for signatures made with the old SHA-1 algorithm remains until Django 4.0.

  Also, the new `algorithm` parameter of the `Signer` allows customizing the hashing algorithm.

#### Template

- The renamed `translate` and `blocktranslate` template tags are introduced for internationalization in template code. The older `trans` and `blocktrans` template tags aliases continue to work, and will be retained for the foreseeable future.

- The `include` template tag now accepts iterables of template names.

#### Tests

- `SimpleTestCase` now implements the `debug()` method to allow running a test without collecting the result and catching exceptions. This can be used to support running tests under a debugger.

- The new `MIGRATE` test database setting allows disabling of migrations during a test database creation.

- `DiscoverRunner` can now discard output for passing tests using the `test --buffer` option.

- `DiscoverRunner` now skips running the system checks on databases not referenced by tests.

- `TransactionTestCase` teardown is now faster on MySQL due to `flush` command improvements. As a side effect the latter doesn’t automatically reset sequences on teardown anymore. Enable `TransactionTestCase.reset_sequences` if your tests require this feature.

#### URLs

- Path converters can now raise `ValueError` in `to_url()` to indicate no match when reversing URLs.

#### Utilities

- `filepath_to_uri()` now supports `pathlib.Path`.

- `parse_duration()` now supports comma separators for decimal fractions in the ISO 8601 format.

- `parse_datetime()`, `parse_duration()`, and `parse_time()` now support comma separators for milliseconds.

#### Miscellanea

- The SQLite backend now supports `pathlib.Path` for the `NAME` setting.

- The `settings.py` generated by the `startproject` command now uses `pathlib.Path` instead of `os.path` for building filesystem paths.

- The `TIME_ZONE` setting is now allowed on databases that support time zones.

## Backwards incompatible changes in 3.1

### Database backend API

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

- `DatabaseOperations.fetch_returned_insert_columns()` now requires an additional `returning_params` argument.

- `connection.timezone` property is now `'UTC'` by default, or the `TIME_ZONE` when `USE_TZ` is `True` on databases that support time zones. Previously, it was `None` on databases that support time zones.

- `connection._nodb_connection` property is changed to the `connection._nodb_cursor()` method and now returns a context manager that yields a cursor and automatically closes the cursor and connection upon exiting the `with` statement.

- `DatabaseClient.runshell()` now requires an additional `parameters` argument as a list of extra arguments to pass on to the command-line client.

- The `sequences` positional argument of `DatabaseOperations.sql_flush()` is replaced by the boolean keyword-only argument `reset_sequences`. If `True`, the sequences of the truncated tables will be reset.

- The `allow_cascade` argument of `DatabaseOperations.sql_flush()` is now a keyword-only argument.

- The `using` positional argument of `DatabaseOperations.execute_sql_flush()` is removed. The method now uses the database of the called instance.

- Third-party database backends must implement support for `JSONField` or set `DatabaseFeatures.supports_json_field` to `False`. If storing primitives is not supported, set `DatabaseFeatures.supports_primitives_in_json_field` to `False`. If there is a true datatype for JSON, set `DatabaseFeatures.has_native_json_field` to `True`. If `jsonfield.contains` and `jsonfield.contained_by` are not supported, set `DatabaseFeatures.supports_json_field_contains` to `False`.

- Third party database backends must implement introspection for `JSONField` or set `can_introspect_json_field` to `False`.

### Dropped support for MariaDB 10.1

Upstream support for MariaDB 10.1 ends in October 2020. Django 3.1 supports MariaDB 10.2 and higher.

### `contrib.admin` browser support

The admin no longer supports the legacy Internet Explorer browser. See the admin FAQ for details on supported browsers.

### `AbstractUser.first_name` `max_length` increased to 150

A migration for `django.contrib.auth.models.User.first_name` is included. If you have a custom user model inheriting from `AbstractUser`, you’ll need to generate and apply a database migration for your user model.

If you want to preserve the 30 character limit for first names, use a custom form:

    from django import forms
    from django.contrib.auth.forms import UserChangeForm

    class MyUserChangeForm(UserChangeForm):
        first_name = forms.CharField(max_length=30, required=False)

If you wish to keep this restriction in the admin when editing users, set `UserAdmin.form` to use this form:

    from django.contrib.auth.admin import UserAdmin
    from django.contrib.auth.models import User

    class MyUserAdmin(UserAdmin):
        form = MyUserChangeForm

    admin.site.unregister(User)
    admin.site.register(User, MyUserAdmin)

### Miscellanea

- The cache keys used by `cache` and generated by `make_template_fragment_key()` are different from the keys generated by older versions of Django. After upgrading to Django 3.1, the first request to any previously cached template fragment will be a cache miss.

- The logic behind the decision to return a redirection fallback or a 204 HTTP response from the `set_language()` view is now based on the `Accept` HTTP header instead of the `X-Requested-With` HTTP header presence.

- The compatibility imports of `django.core.exceptions.EmptyResultSet` in `django.db.models.query`, `django.db.models.sql`, and `django.db.models.sql.datastructures` are removed.

- The compatibility import of `django.core.exceptions.FieldDoesNotExist` in `django.db.models.fields` is removed.

- The compatibility imports of `django.forms.utils.pretty_name()` and `django.forms.boundfield.BoundField` in `django.forms.forms` are removed.

- The compatibility imports of `Context`, `ContextPopException`, and `RequestContext` in `django.template.base` are removed.

- The compatibility import of `django.contrib.admin.helpers.ACTION_CHECKBOX_NAME` in `django.contrib.admin` is removed.

- The `STATIC_URL` and `MEDIA_URL` settings set to relative paths are now prefixed by the server-provided value of `SCRIPT_NAME` (or `/` if not set). This change should not affect settings set to valid URLs or absolute paths.

- `ConditionalGetMiddleware` no longer adds the `ETag` header to responses with an empty `content`.

- `django.utils.decorators.classproperty()` decorator is made public and moved to `django.utils.functional.classproperty`.

- `floatformat` template filter now outputs (positive) `0` for negative numbers which round to zero.

- `Meta.ordering` and `Meta.unique_together` options on models in `django.contrib` modules that were formerly tuples are now lists.

- The admin calendar widget now handles two-digit years according to the Open Group Specification, i.e. values between 69 and 99 are mapped to the previous century, and values between 0 and 68 are mapped to the current century.

- Date-only formats are removed from the default list for `DATETIME_INPUT_FORMATS`.

- The `FileInput` widget no longer renders with the `required` HTML attribute when initial data exists.

- The undocumented `django.views.debug.ExceptionReporterFilter` class is removed. As per the Rapporti di errore personalizzati documentation, classes to be used with `DEFAULT_EXCEPTION_REPORTER_FILTER` need to inherit from `django.views.debug.SafeExceptionReporterFilter`.

- The cache timeout set by `cache_page()` decorator now takes precedence over the `max-age` directive from the `Cache-Control` header.

- Providing a non-local remote field in the `ForeignKey.to_field` argument now raises `FieldError`.

- `SECURE_REFERRER_POLICY` now defaults to `'same-origin'`. See the What’s New Security section above for more details.

- `check` management command now runs the `database` system checks only for database aliases specified using `check --database` option.

- `migrate` management command now runs the `database` system checks only for a database to migrate.

- The admin CSS classes `row1` and `row2` are removed in favor of `:nth-child(odd)` and `:nth-child(even)` pseudo-classes.

- The `make_password()` function now requires its argument to be a string or bytes. Other types should be explicitly cast to one of these.

- The undocumented `version` parameter to the `AsKML` function is removed.

- JSON and YAML serializers, used by `dumpdata`, now dump all data with Unicode by default. If you need the previous behavior, pass `ensure_ascii=True` to JSON serializer, or `allow_unicode=False` to YAML serializer.

- The auto-reloader no longer monitors changes in built-in Django translation files.

- The minimum supported version of `mysqlclient` is increased from 1.3.13 to 1.4.0.

- The undocumented `django.contrib.postgres.forms.InvalidJSONInput` and `django.contrib.postgres.forms.JSONString` are moved to `django.forms.fields`.

- The undocumented `django.contrib.postgres.fields.jsonb.JsonAdapter` class is removed.

- The `{% localize off %}` tag and `unlocalize` filter no longer respect `DECIMAL_SEPARATOR` setting.

- The minimum supported version of `asgiref` is increased from 3.2 to 3.2.10.

- The Media class now renders `<script>` tags without the `type` attribute to follow WHATWG recommendations.

- `ModelChoiceIterator`, used by `ModelChoiceField` and `ModelMultipleChoiceField`, now yields 2-tuple choices containing `ModelChoiceIteratorValue` instances as the first `value` element in each choice. In most cases this proxies transparently, but if you need the `field` value itself, use the `ModelChoiceIteratorValue.value` attribute instead.

## Features deprecated in 3.1

### PostgreSQL `JSONField`

`django.contrib.postgres.fields.JSONField` and `django.contrib.postgres.forms.JSONField` are deprecated in favor of `models.JSONField` and `forms.JSONField`.

The undocumented `django.contrib.postgres.fields.jsonb.KeyTransform` and `django.contrib.postgres.fields.jsonb.KeyTextTransform` are also deprecated in favor of the transforms in `django.db.models.fields.json`.

The new `JSONField`s, `KeyTransform`, and `KeyTextTransform` can be used on all supported database backends.

### Miscellanea

- `PASSWORD_RESET_TIMEOUT_DAYS` setting is deprecated in favor of `PASSWORD_RESET_TIMEOUT`.

- The undocumented usage of the `isnull` lookup with non-boolean values as the right-hand side is deprecated, use `True` or `False` instead.

- The barely documented `django.db.models.query_utils.InvalidQuery` exception class is deprecated in favor of `FieldDoesNotExist` and `FieldError`.

- The `django-admin.py` entry point is deprecated in favor of `django-admin`.

- The `HttpRequest.is_ajax()` method is deprecated as it relied on a jQuery-specific way of signifying AJAX calls, while current usage tends to use the JavaScript Fetch API. Depending on your use case, you can either write your own AJAX detection method, or use the new `HttpRequest.accepts()` method if your code depends on the client `Accept` HTTP header.

  If you are writing your own AJAX detection method, `request.is_ajax()` can be reproduced exactly as `request.headers.get('x-requested-with') == 'XMLHttpRequest'`.

- Passing `None` as the first argument to `django.utils.deprecation.MiddlewareMixin.__init__()` is deprecated.

- The encoding format of cookies values used by `CookieStorage` is different from the format generated by older versions of Django. Support for the old format remains until Django 4.0.

- The encoding format of sessions is different from the format generated by older versions of Django. Support for the old format remains until Django 4.0.

- The purely documentational `providing_args` argument for `Signal` is deprecated. If you rely on this argument as documentation, you can move the text to a code comment or docstring.

- Calling `django.utils.crypto.get_random_string()` without a `length` argument is deprecated.

- The `list` message for `ModelMultipleChoiceField` is deprecated in favor of `invalid_list`.

- Passing raw column aliases to `QuerySet.order_by()` is deprecated. The same result can be achieved by passing aliases in a `RawSQL` instead beforehand.

- The `NullBooleanField` model field is deprecated in favor of `BooleanField(null=True, blank=True)`.

- `django.conf.urls.url()` alias of `django.urls.re_path()` is deprecated.

- The `{% ifequal %}` and `{% ifnotequal %}` template tags are deprecated in favor of `{% if %}`. `{% if %}` covers all use cases, but if you need to continue using these tags, they can be extracted from Django to a module and included as a built-in tag in the `'builtins'` option in `OPTIONS`.

- `DEFAULT_HASHING_ALGORITHM` transitional setting is deprecated.

## Features removed in 3.1

These features have reached the end of their deprecation cycle and are removed in Django 3.1.

See Features deprecated in 2.2 for details on these changes, including how to remove usage of these features.

- `django.utils.timezone.FixedOffset` is removed.

- `django.core.paginator.QuerySetPaginator` is removed.

- A model’s `Meta.ordering` doesn’t affect `GROUP BY` queries.

- `django.contrib.postgres.fields.FloatRangeField` and `django.contrib.postgres.forms.FloatRangeField` are removed.

- The `FILE_CHARSET` setting is removed.

- `django.contrib.staticfiles.storage.CachedStaticFilesStorage` is removed.

- The `RemoteUserBackend.configure_user()` method requires `request` as the first positional argument.

- Support for `SimpleTestCase.allow_database_queries` and `TransactionTestCase.multi_db` is removed.