- Fix recursive WorkController instantiation in DjangoWorkerFixup + AttributeError when pool_cls is a string (#10045)
- Bugfix: Revoked tasks now immediately update backend status to REVOKED (#9869)
- Prepare for release: v5.6.2 (#10049)

.. _version-5.6.1:

5.6.1
=====

:release-date: 2025-12-29
:release-by: Tomer Nosrati

What's Changed

See :ref:`whatsnew-5.6` for a complete overview or read the main highlights below.

Python 3.9 Minimum Version
--------------------------

Celery 5.6.0 drops support for Python 3.8 (EOL). The minimum required Python
version is now 3.9. Users still on Python 3.8 must upgrade their Python version
before upgrading to Celery 5.6.0.

Additionally, this release includes initial support for Python 3.14.

SQS: Reverted to ``pycurl`` from ``urllib3``
--------------------------------------------

The switch from ``pycurl`` to ``urllib3`` for the SQS transport (introduced in
Celery 5.5.0 via Kombu) has been reverted due to critical issues affecting SQS
users:

- Processing throughput dropped from ~100 tasks/sec to ~3/sec in some environments
- ``UnknownOperationException`` errors causing container crash loops
- Silent message processing failures with no error logs

Users of the SQS transport must ensure ``pycurl`` is installed. If you removed
``pycurl`` after upgrading to Celery 5.5.0, you will need to reinstall it.

Contributed by `@auvipy <https://github.com/auvipy>`_ in
`#9620 <https://github.com/celery/celery/pull/9620>`_.

Security Fix: Broker Credential Leak Prevention
------------------------------------------------

Fixed a security issue where broker URLs containing passwords were being logged
in plaintext by the delayed delivery mechanism. Broker credentials are now
properly sanitized in all log output.

Contributed by `@giancarloromeo <https://github.com/giancarloromeo>`_ in
`#9997 <https://github.com/celery/celery/pull/9997>`_.

Memory Leak Fixes
-----------------

Two significant memory leaks have been fixed in this release:

**Exception Handling Memory Leak**: Fixed a critical memory leak in task exception
handling that was particularly severe on Python 3.11+ due to enhanced traceback
data. The fix properly breaks reference cycles in tracebacks to allow garbage
collection.

Contributed by `@jaiganeshs21 <https://github.com/jaiganeshs21>`_ in
`#9799 <https://github.com/celery/celery/pull/9799>`_.

**Pending Result Memory Leak**: Fixed a memory leak where ``AsyncResult``
subscriptions were not being cleaned up when results were forgotten.

Contributed by `@tsoos99dev <https://github.com/tsoos99dev>`_ in
`#9806 <https://github.com/celery/celery/pull/9806>`_.

ETA Task Memory Limit
---------------------

New configuration option :setting:`worker_eta_task_limit` to prevent out-of-memory
crashes when workers fetch large numbers of ETA or countdown tasks. Previously,
workers could exhaust available memory when the broker contained many scheduled tasks.

Example usage:

.. code-block:: python

    app.conf.worker_eta_task_limit = 1000

Contributed by `@sashu2310 <https://github.com/sashu2310>`_ in
`#9853 <https://github.com/celery/celery/pull/9853>`_.

Queue Type Selection for Auto-created Queues
--------------------------------------------

New configuration options allow specifying the queue type and exchange type when
Celery auto-creates missing queues. This is particularly useful for RabbitMQ users
who want to use quorum queues with auto-created queues.

Configuration options:

- :setting:`task_create_missing_queue_type`: Sets the queue type for auto-created
  queues (e.g., ``quorum``, ``classic``)
- :setting:`task_create_missing_queue_exchange_type`: Sets the exchange type for
  auto-created queues

Example usage:

.. code-block:: python

    app.conf.task_create_missing_queue_type = 'quorum'

Contributed by `@ghirailghiro <https://github.com/ghirailghiro>`_ in
`#9815 <https://github.com/celery/celery/pull/9815>`_.

What's Changed

- Remove Python 4.0 version condition for pytest dependencies (#9993)
- Sanitize broker URL in delayed delivery logs (avoid leaking credentials) (#9997)
- Don't fail task on timeout during cold shutdown (#9678)
- Add Py39-314t to CI (#9999)
- asynpool: Don't return from inside a finally block (#10000)
- Prepare for (pre) release: v5.6.0rc2 (#10005)

.. _version-5.6.0rc1:

5.6.0rc1
========

:release-date: 2025-11-02
:release-by: Tomer Nosrati

Celery v5.6.0 Release Candidate 1 is now available for testing.
Please help us test this version and report any issues.

What's Changed

- GitHub Actions: Test on Python 3.14 release candidate 2 (#9891)
- Update pypy to python 3.11 (#9896)
- Feature: Add support credential_provider to Redis Backend (#9879)
- Celery.timezone: try tzlocal.get_localzone() before using LocalTimezone (#9862)
- Run integration tests on Python 3.14 (#9903)
- Fix arithmetic overflow for MSSQL result backend (#9904)
- Add documentation for task_id param for apply_async function (#9906)
- Support redis client name (#9900)
- Bump Kombu to v5.6.0rc1 (#9918)
- Fix broker connection retry attempt counter in the error log (#9911)
- fix: restrict disable-prefetch feature to Redis brokers only (#9919)
- fix(): preserve group order in replaced signature (#9910)
- Remove Python 3.8 from CI workflow (#9930)
- Update default Python versions in integration tests (#9931)
- Update tox.ini to remove Python 3.8 (#9932)
- Remove Python 3.8 from Dockerfile (#9933)
- Update Python version requirement to 3.9 (#9935)
- Update pypy version from 3.10 to 3.11 in Dockerfile (#9934)
- Flake8 fixes (#9955)
- Remove test-pypy3.txt from Dockerfile dependencies (#9939)
- Remove backports.zoneinfo for Python 3.9 compatibility (#9956)
- Update pytest-cov version for Python compatibility (#9957)
- Update pytest-rerunfailures and pre-commit versions (#9958)
- Prepare for (pre) release: v5.6.0b2 (#9938)

.. _version-5.6.0b1:

5.6.0b1
=======

:release-date: 2025-09-15
:release-by: Tomer Nosrati

Celery v5.6.0 Beta 1 is now available for testing.
Please help us test this version and report any issues.

What's Changed