{"title":"Django 4.2 release notes","version":"dev","locale":"en","docname":"releases/4.2","url":"/en/dev/releases/4.2/","canonical":"https://djangodocs.dev/en/dev/releases/4.2/","summary":"Welcome to Django 4.2! These release notes cover the new features, as well as some backwards incompatible changes you’ll want to be aware of when upgrading…","html":"

Django 4.2 release notesLink to this heading#

\n

April 3, 2023

\n

Welcome to Django 4.2!

\n

These release notes cover the new features, as well as\nsome backwards incompatible changes you’ll\nwant to be aware of when upgrading from Django 4.1 or earlier. We’ve\nbegun the deprecation process for some features.

\n

See the How to upgrade Django to a newer version guide if you’re updating an existing\nproject.

\n

Django 4.2 is designated as a long-term support release. It will receive security updates for at least\nthree years after its release. Support for the previous LTS, Django 3.2, will\nend in April 2024.

\n
\n

Python compatibilityLink to this heading#

\n

Django 4.2 supports Python 3.8, 3.9, 3.10, 3.11, and 3.12 (as of 4.2.8). We\nhighly recommend and only officially support the latest release of each\nseries.

\n
\n
\n

What’s new in Django 4.2Link to this heading#

\n
\n

Psycopg 3 supportLink to this heading#

\n

Django now supports psycopg version 3.1.8 or higher. To update your code,\ninstall the psycopg library, you don’t need to change the\nENGINE as django.db.backends.postgresql\nsupports both libraries.

\n

Support for psycopg2 is likely to be deprecated and removed at some point\nin the future.

\n

Be aware that psycopg 3 introduces some breaking changes over psycopg2.\nAs a consequence, you may need to make some changes to account for\ndifferences from psycopg2.

\n
\n
\n

Comments on columns and tablesLink to this heading#

\n

The new Field.db_comment and\nMeta.db_table_comment\noptions allow creating comments on columns and tables, respectively. For\nexample:

\n
Code
from django.db import models\n\n\nclass Question(models.Model):\n    text = models.TextField(db_comment="Poll question")\n    pub_date = models.DateTimeField(\n        db_comment="Date and time when the question was published",\n    )\n\n    class Meta:\n        db_table_comment = "Poll questions"\n\n\nclass Answer(models.Model):\n    question = models.ForeignKey(\n        Question,\n        on_delete=models.CASCADE,\n        db_comment="Reference to a question",\n    )\n    answer = models.TextField(db_comment="Question answer")\n\n    class Meta:\n        db_table_comment = "Question answers"\n
\n

Also, the new AlterModelTableComment\noperation allows changing table comments defined in the\nMeta.db_table_comment.

\n
\n
\n

Mitigation for the BREACH attackLink to this heading#

\n

GZipMiddleware now includes a mitigation for\nthe BREACH attack. It will add up to 100 random bytes to gzip responses to make\nBREACH attacks harder. Read more about the mitigation technique in the Heal\nThe Breach (HTB) paper.

\n
\n
\n

In-memory file storageLink to this heading#

\n

The new django.core.files.storage.InMemoryStorage class provides a\nnon-persistent storage useful for speeding up tests by avoiding disk access.

\n
\n
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Custom file storagesLink to this heading#

\n

The new STORAGES setting allows configuring multiple custom file\nstorage backends. It also controls storage engines for managing\nfiles (the "default" key) and static files (the "staticfiles" key).

\n

The old DEFAULT_FILE_STORAGE and STATICFILES_STORAGE settings are\ndeprecated as of this release.

\n
\n
\n

Minor featuresLink to this heading#

\n
\n

django.contrib.adminLink to this heading#

\n
    \n

  • The light or dark color theme of the admin can now be toggled in the UI, as\nwell as being set to follow the system setting.

    • \n

  • The admin’s font stack now prefers system UI fonts and no longer requires\ndownloading fonts. Additionally, CSS variables are available to more easily\noverride the default font families.

    • \n

  • The admin/delete_confirmation.html template now\nhas some additional blocks and scripting hooks to ease customization.

    • \n

  • The chosen options of\nfilter_horizontal and\nfilter_vertical widgets are now\nfilterable.

    • \n

  • The admin/base.html template now has a new block nav-breadcrumbs\nwhich contains the navigation landmark and the breadcrumbs block.

    • \n

  • ModelAdmin.list_editable now uses atomic transactions when making\nedits.

    • \n

  • jQuery is upgraded from version 3.6.0 to 3.6.4.

    • \n
\n
\n
\n

django.contrib.authLink to this heading#

\n
    \n

  • The default iteration count for the PBKDF2 password hasher is increased from\n390,000 to 600,000.

    • \n

  • UserCreationForm now saves many-to-many\nform fields for a custom user model.

    • \n

  • The new BaseUserCreationForm is now the\nrecommended base class for customizing the user creation form.

    • \n
\n
\n
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django.contrib.gisLink to this heading#

\n
    \n

  • The GeoJSON serializer now outputs the\nid key for serialized features, which defaults to the primary key of\nobjects.

    • \n

  • The GDALRaster class now supports\npathlib.Path.

    • \n

  • The GeoIP2 class now supports .mmdb\nfiles downloaded from DB-IP.

    • \n

  • The OpenLayers template widget no longer includes inline CSS (which also\nremoves the former map_css block) to better comply with a strict Content\nSecurity Policy.

    • \n

  • OpenLayersWidget is now based on\nOpenLayers 7.2.2 (previously 4.6.5).

    • \n

  • The new isempty lookup and\nIsEmpty()\nexpression allow filtering empty geometries on PostGIS.

    • \n

  • The new FromWKB()\nand FromWKT()\nfunctions allow creating geometries from Well-known binary (WKB) and\nWell-known text (WKT) representations.

    • \n
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django.contrib.postgresLink to this heading#

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\n
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django.contrib.sitemapsLink to this heading#

\n\n
\n
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django.contrib.staticfilesLink to this heading#

\n
    \n

  • ManifestStaticFilesStorage now\nhas experimental support for replacing paths to JavaScript modules in\nimport and export statements with their hashed counterparts. If you\nwant to try it, subclass ManifestStaticFilesStorage and set the\nsupport_js_module_import_aggregation attribute to True.

    • \n

  • The new ManifestStaticFilesStorage.manifest_hash attribute provides\na hash over all files in the manifest and changes whenever one of the files\nchanges.

    • \n
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Database backendsLink to this heading#

\n\n
\n
\n

Error ReportingLink to this heading#

\n
    \n

  • The debug page now shows exception notes and\nfine-grained error locations on Python 3.11+.

    • \n

  • Session cookies are now treated as credentials and therefore hidden and\nreplaced with stars (**********) in error reports.

    • \n
\n
\n
\n

FormsLink to this heading#

\n
    \n

  • ModelForm now accepts the new Meta option\nformfield_callback to customize form fields.

    • \n

  • modelform_factory() now respects the\nformfield_callback attribute of the form’s Meta.

    • \n
\n
\n
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InternationalizationLink to this heading#

\n
    \n

  • Added support and translations for the Central Kurdish (Sorani) language.

    • \n
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\n
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LoggingLink to this heading#

\n
    \n

  • The django.db.backends logger now logs transaction management queries\n(BEGIN, COMMIT, and ROLLBACK) at the DEBUG level.

    • \n
\n
\n
\n

Management CommandsLink to this heading#

\n
    \n

  • makemessages command now supports locales with private sub-tags\nsuch as nl_NL-x-informal.

    • \n

  • The new makemigrations --update option merges model changes into\nthe latest migration and optimizes the resulting operations.

    • \n
\n
\n
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MigrationsLink to this heading#

\n
    \n

  • Migrations now support serialization of enum.Flag objects.

    • \n
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\n
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ModelsLink to this heading#

\n
    \n

  • QuerySet now extensively supports filtering against\nUUID functions with the exception of disjunctive filter lookups\nagainst window functions when performing aggregation.

    • \n

  • prefetch_related() now supports\nPrefetch objects with sliced querysets.

    • \n

  • Registering lookups on\nField instances is now supported.

    • \n

  • The new robust argument for on_commit()\nallows performing actions that can fail after a database transaction is\nsuccessfully committed.

    • \n

  • The new KT() expression represents\nthe text value of a key, index, or path transform of\nJSONField.

    • \n

  • Now now supports microsecond precision\non MySQL and millisecond precision on SQLite.

    • \n

  • F() expressions that output BooleanField\ncan now be negated using ~F() (inversion operator).

    • \n

  • Model now provides asynchronous versions of some methods that use the\ndatabase, using an a prefix: adelete(),\narefresh_from_db(), and asave().

    • \n

  • Related managers now provide asynchronous versions of methods that change a\nset of related objects, using an a prefix: aadd(),\naclear(), aremove(), and\naset().

    • \n

  • CharField.max_length is no\nlonger required to be set on PostgreSQL, which supports unlimited VARCHAR\ncolumns.

    • \n
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Requests and ResponsesLink to this heading#

\n\n
\n
\n

TestsLink to this heading#

\n
    \n

  • The test --debug-sql option now formats SQL queries with\nsqlparse.

    • \n

  • The RequestFactory,\nAsyncRequestFactory, Client, and\nAsyncClient classes now support the headers\nparameter, which accepts a dictionary of header names and values. This allows\na more natural syntax for declaring headers.

    \n
    Python
    # Before:\nself.client.get("/home/", HTTP_ACCEPT_LANGUAGE="fr")\nawait self.async_client.get("/home/", ACCEPT_LANGUAGE="fr")\n\n# After:\nself.client.get("/home/", headers={"accept-language": "fr"})\nawait self.async_client.get("/home/", headers={"accept-language": "fr"})\n
    \n
    • \n
\n
\n
\n

UtilitiesLink to this heading#

\n
    \n

  • The new encoder parameter for django.utils.html.json_script()\nfunction allows customizing a JSON encoder class.

    • \n

  • The private internal vendored copy of urllib.parse.urlsplit() now strips\n'\\r', '\\n', and '\\t' (see CVE 2022-0391 and bpo-43882).\nThis is to protect projects that may be incorrectly using the internal\nurl_has_allowed_host_and_scheme() function, instead of using one of the\ndocumented functions for handling URL redirects. The Django functions were\nnot affected.

    • \n

  • The new django.utils.http.content_disposition_header() function returns\na Content-Disposition HTTP header value as specified by RFC 6266.

    • \n
\n
\n
\n

ValidatorsLink to this heading#

\n
    \n

  • The list of common passwords used by CommonPasswordValidator is updated\nto the most recent version.

    • \n
\n
\n
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\n
\n

Backwards incompatible changes in 4.2Link to this heading#

\n
\n

Database backend APILink to this heading#

\n

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

\n\n
\n
\n

Dropped support for MariaDB 10.3Link to this heading#

\n

Upstream support for MariaDB 10.3 ends in May 2023. Django 4.2 supports MariaDB\n10.4 and higher.

\n
\n
\n

Dropped support for MySQL 5.7Link to this heading#

\n

Upstream support for MySQL 5.7 ends in October 2023. Django 4.2 supports MySQL\n8 and higher.

\n
\n
\n

Dropped support for PostgreSQL 11Link to this heading#

\n

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

\n
\n
\n

Setting update_fields in Model.save() may now be requiredLink to this heading#

\n

In order to avoid updating unnecessary columns,\nQuerySet.update_or_create() now passes update_fields to the\nModel.save() calls. As a consequence, any\nfields modified in the custom save() methods should be added to the\nupdate_fields keyword argument before calling super(). See\nOverriding predefined model methods for more details.

\n
\n
\n

Dropped support for raw aggregations on MySQLLink to this heading#

\n

MySQL 8+ allows functional dependencies on GROUP BY columns, so the\npre-Django 4.2 workaround of grouping by primary keys of the main table is\nremoved. As a consequence, using RawSQL() aggregations is no longer\nsupported on MySQL as there is no way to determine if such aggregations are\nneeded or valid in the GROUP BY clause. Use Aggregation functions\ninstead.

\n
\n
\n

MiscellaneousLink to this heading#

\n\n
\n
\n
\n

Features deprecated in 4.2Link to this heading#

\n
\n

index_together option is deprecated in favor of indexesLink to this heading#

\n

The Meta.index_together option is deprecated in favor of the\nindexes option.

\n

Migrating existing index_together should be handled as a migration. For\nexample:

\n
Code
class Author(models.Model):\n    rank = models.IntegerField()\n    name = models.CharField(max_length=30)\n\n    class Meta:\n        index_together = [["rank", "name"]]\n
\n

Should become:

\n
Code
class Author(models.Model):\n    rank = models.IntegerField()\n    name = models.CharField(max_length=30)\n\n    class Meta:\n        indexes = [models.Index(fields=["rank", "name"])]\n
\n

Running the makemigrations command will generate a migration\ncontaining a RenameIndex operation\nwhich will rename the existing index. Next, consider squashing migrations to\nremove index_together from historical migrations.

\n

The AlterIndexTogether migration operation is now officially supported only\nfor pre-Django 4.2 migration files. For backward compatibility reasons, it’s\nstill part of the public API, and there’s no plan to deprecate or remove it,\nbut it should not be used for new migrations. Use\nAddIndex and\nRemoveIndex operations instead.

\n
\n
\n

Passing encoded JSON string literals to JSONField is deprecatedLink to this heading#

\n

JSONField and its associated lookups and aggregates used to allow passing\nJSON encoded string literals which caused ambiguity on whether string literals\nwere already encoded from database backend’s perspective.

\n

During the deprecation period string literals will be attempted to be JSON\ndecoded and a warning will be emitted on success that points at passing\nnon-encoded forms instead.

\n

Code that used to pass JSON encoded string literals:

\n
Code
Document.objects.bulk_create(\n    Document(data=Value("null")),\n    Document(data=Value("[]")),\n    Document(data=Value('"foo-bar"')),\n)\nDocument.objects.annotate(\n    JSONBAgg("field", default=Value("[]")),\n)\n
\n

Should become:

\n
Code
Document.objects.bulk_create(\n    Document(data=Value(None, JSONField())),\n    Document(data=[]),\n    Document(data="foo-bar"),\n)\nDocument.objects.annotate(\n    JSONBAgg("field", default=[]),\n)\n
\n

From Django 5.1+ string literals will be implicitly interpreted as JSON string\nliterals.

\n
\n
\n

MiscellaneousLink to this heading#

\n\n
\n
","rootId":"django-4-2-release-notes","toc":[{"title":"Python compatibility","anchor":"python-compatibility","children":[]},{"title":"What’s new in Django 4.2","anchor":"what-s-new-in-django-4-2","children":[{"title":"Psycopg 3 support","anchor":"psycopg-3-support","children":[]},{"title":"Comments on columns and tables","anchor":"comments-on-columns-and-tables","children":[]},{"title":"Mitigation for the BREACH attack","anchor":"mitigation-for-the-breach-attack","children":[]},{"title":"In-memory file storage","anchor":"in-memory-file-storage","children":[]},{"title":"Custom file storages","anchor":"custom-file-storages","children":[]},{"title":"Minor features","anchor":"minor-features","children":[{"title":"django.contrib.admin","anchor":"django-contrib-admin","children":[]},{"title":"django.contrib.auth","anchor":"django-contrib-auth","children":[]},{"title":"django.contrib.gis","anchor":"django-contrib-gis","children":[]},{"title":"django.contrib.postgres","anchor":"django-contrib-postgres","children":[]},{"title":"django.contrib.sitemaps","anchor":"django-contrib-sitemaps","children":[]},{"title":"django.contrib.staticfiles","anchor":"django-contrib-staticfiles","children":[]},{"title":"Database backends","anchor":"database-backends","children":[]},{"title":"Error Reporting","anchor":"error-reporting","children":[]},{"title":"Forms","anchor":"forms","children":[]},{"title":"Internationalization","anchor":"internationalization","children":[]},{"title":"Logging","anchor":"logging","children":[]},{"title":"Management Commands","anchor":"management-commands","children":[]},{"title":"Migrations","anchor":"migrations","children":[]},{"title":"Models","anchor":"models","children":[]},{"title":"Requests and Responses","anchor":"requests-and-responses","children":[]},{"title":"Tests","anchor":"tests","children":[]},{"title":"Utilities","anchor":"utilities","children":[]},{"title":"Validators","anchor":"validators","children":[]}]}]},{"title":"Backwards incompatible changes in 4.2","anchor":"backwards-incompatible-changes-in-4-2","children":[{"title":"Database backend API","anchor":"database-backend-api","children":[]},{"title":"Dropped support for MariaDB 10.3","anchor":"dropped-support-for-mariadb-10-3","children":[]},{"title":"Dropped support for MySQL 5.7","anchor":"dropped-support-for-mysql-5-7","children":[]},{"title":"Dropped support for PostgreSQL 11","anchor":"dropped-support-for-postgresql-11","children":[]},{"title":"Setting update_fields in Model.save() may now be required","anchor":"setting-update-fields-in-model-save-may-now-be-required","children":[]},{"title":"Dropped support for raw aggregations on MySQL","anchor":"dropped-support-for-raw-aggregations-on-mysql","children":[]},{"title":"Miscellaneous","anchor":"miscellaneous","children":[]}]},{"title":"Features deprecated in 4.2","anchor":"features-deprecated-in-4-2","children":[{"title":"index_together option is deprecated in favor of indexes","anchor":"index-together-option-is-deprecated-in-favor-of-indexes","children":[]},{"title":"Passing encoded JSON string literals to JSONField is deprecated","anchor":"passing-encoded-json-string-literals-to-jsonfield-is-deprecated","children":[]},{"title":"Miscellaneous","anchor":"id1","children":[]}]}],"breadcrumbs":[{"docname":"releases/index","title":"Release notes","url":"/en/dev/releases/"}],"prev":{"docname":"releases/4.2.1","title":"Django 4.2.1 release notes","url":"/en/dev/releases/4.2.1/"},"next":{"docname":"releases/4.1.13","title":"Django 4.1.13 release notes","url":"/en/dev/releases/4.1.13/"},"formats":{"html":"/en/dev/releases/4.2/","markdown":"/en/dev/releases/4.2.md","json":"/en/dev/releases/4.2.json"},"source":"https://github.com/django/django/blob/main/docs/releases/4.2.txt","official":"https://docs.djangoproject.com/en/dev/releases/4.2/","inVersions":["dev","6.1","6.0","5.2","5.1","5.0","4.2"],"inLocales":["en"]}