Django MongoDB Backend 5.2.x

5.2.3

Unreleased

New features

• …

Bug fixes

• Prevented QuerySet.union() queries from duplicating the $project pipeline.

5.2.2

October 22, 2025

This release confirms support for Python 3.14. No code changes were required.

New features

• SearchIndex's new field_mappings, analyzer, and search_analyzer arguments allow creating more complex indexes.

Bug fixes

• Fixed a KeyError crash when loading models with EmbeddedModel fields that use a database converter, if the field isn’t present in the data (e.g. data not written by Django, or after a field was added to an existing EmbeddedModel).

• Made EmbeddedModel fields respect db_column.

• Corrected the search index type of EmbeddedModelField and PolymorphicEmbeddedModelField from embeddedDocuments to document.

• Fixed transaction.atomic() crash if the database connection isn’t initialized.

Performance improvements

• Continued the query optimization work started in 5.2.1, making queries avoid using $expr where possible, so that they can use indexes.

Deprecated features

• django_mongodb_backend.utils.parse_uri() is deprecated in favor of putting the connection string in DATABASES["HOST"]. See the deprecation timeline for upgrade instructions.

5.2.1

September 8, 2025

New features

• Allowed specifying the MongoDB connection string in DATABASES["HOST"], eliminating the need to use parse_uri() to configure the DATABASES setting.

Bug fixes

• Migrations operations that add or delete search indexes now wait until the operation is completed on the server to prevent conflicts when running multiple operations sequentially.

Performance improvements

• Made simple queries that use $eq, $in, $and, $or, $gt, $gte, $lt, and/or $lte use $match instead of $expr so that they can use indexes.

5.2.0

September 2, 2025

General availability release. No changes since beta 3.

5.2.0 beta 3

August 29, 2025

Backwards incompatible changes

• Pattern matching lookups (iexact, startswith, istartswith, endswith, iendswith, contains, icontains, regex, and iregex) no longer support non-string fields. These lookups previously cast their input using $toString but this caused some queries to perform poorly because MongoDB couldn’t use indexes when running the query.

5.2.0 beta 2

August 13, 2025

New features

• Added support for Atlas Search queries.

• Added subquery support for EmbeddedModelArrayField.

• Added the options parameter to parse_uri().

• Added support for database transactions.

• Added PolymorphicEmbeddedModelField and PolymorphicEmbeddedModelArrayField for storing a model instance or list of model instances that may be of more than one model class.

• Added GeoDjango support.

• Added Queryable Encryption support.

Backwards incompatible changes

• django.db.models.SmallIntegerField and django.db.models.PositiveSmallIntegerField are now limited to 32 bit values in forms and model validation.

• Removed support for database caching as the MongoDB security team considers the cache backend’s pickle encoding of cached values a vulnerability. If an attacker compromises the database, they could run arbitrary commands on the application server.

Bug fixes

• Fixed RecursionError when using Trunc database functions on non-MongoDB databases.

• QuerySet.explain() now returns a string that can be parsed as JSON.

• Fixed unique constraint generation for IntegerField and PositiveBigIntegerField, which incorrectly allowed duplicate values larger than 32 bits. Existing unique constraints must be recreated to use $type: long instead of int.

• IntegerField, BigIntegerField (as well as the Positive versions of these fields), and DurationField values are now sent to MongoDB as bson.int64.Int64, which fixes unique constraints on values less than 32 bits for BigIntegerField, PositiveIntegerField, and DurationField. Existing data must be converted to Int64.

Performance improvements

• Improved QuerySet performance by removing low limit on server-side chunking.

• Improved QuerySet join ($lookup) performance by pushing some simple conditions from the WHERE ($match) clause to the $lookup stage.

5.2.0 beta 1

June 4, 2025

New features

• Added EmbeddedModelArrayField for storing a list of model instances.

Bug fixes

• Fixed crash when loading models with a null value for ArrayFields where the base_field uses a database converter.

5.2.0 beta 0

May 14, 2025

Initial release from the state of django-mongodb-backend 5.1.0 beta 2.

Regarding new features in Django 5.2, CompositePrimaryKey isn’t supported.

New features

These features won’t appear in Django MongoDB Backend 5.1.x.

• Added SearchIndex and VectorSearchIndex for use on a model’s Meta.indexes.

• PyMongo’s connection pooling is now used by default. See Connection management.

Backwards incompatible changes

• The minimum supported version of pymongo is increased from 4.6 to 4.7.

• The conn_max_age parameter of parse_uri() is removed because persistent connections are now used by default.

Bug fixes

• Added support for a field’s custom lookups and transforms in EmbeddedModelField, e.g. ArrayField’s contains, contained__by, len, etc.

• Fixed the results of queries that use the tzinfo parameter of the Trunc database functions.

• Added support for QuerySet.dates() and datetimes().

• Fixed loading of QuerySet results for embedded models that have fields that use database converters. For example, a crash for DecimalField: ValidationError: ['“1” value must be a decimal number.']).