Celery

Distributed task queue for Python. Current version is 5.6.2 (Jan 2026). Requires Python >=3.9. A broker (Redis or RabbitMQ) is always required — there is no built-in broker. Old lowercase config settings (CELERY_TASK_SERIALIZER etc.) removed in Celery 5.0. SQS transport: pycurl→urllib3 in 5.5, then reverted in 5.6 — SQS users need pycurl reinstalled after 5.5→5.6 upgrade. Security fix: broker URL passwords were logged in plaintext before 5.6.