# What changed in kombu

> 21 changes in kombu 5 from its official release notes, upgrade guides and advisories: 2 breaking, 1 security, 4 new APIs and options. Each one cited. Sources checked 2026-10-25. HTML: https://unstale.sh/pypi/kombu/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## kombu 5

### Breaking changes

- MongoDB URI options are lowercase and flattened, so settings such as replicaSet=test_rs appear as options['replicaset']. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)
- UTC datetimes are now timezone-aware, using datetime.now(timezone.utc) instead of datetime.utcnow(). (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)

### Security

- AWS SSL transport validates secure connections. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)

### New APIs and options

- Adds support for credential_provider with the Redis broker. (5.6.1) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.1)
- QoS accepts an optional max_prefetch parameter to cap how many messages workers hold in memory; it defaults to unlimited (None). (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)
- Adds sts_token_buffer_time to SQS transport options. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)
- SQS queue tags can be set in the initial boto3.sqs.create_queue call via transport_options. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)

### Performance

- Removes a nested query from SQLAlchemy _size. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)

### Behavior and default changes

- Fixes the default value for SQS receive message. (5.6.1) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.1)
- Redis transport, including Sentinel, propagates the client_name connection parameter so connections appear with meaningful names in monitoring tools. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)
- SQS support for receiving message attributes is enhanced, and string message bodies are allowed. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)

### Fixes and other changes

- Improves error handling during ack deadline extension. (5.6.2) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.2)
- Fixes credential_provider compatibility with redis versions below 5.3.0. (5.6.2) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.2)
- Passes ACL credentials to master_for() when using SentinelChannel. (5.6.2) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.2)
- Closing the hub now also removes the global event loop reference. (5.6.1) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.1)
- Redis transport now propagates brpop_timeout from transport_options to the Channel's _brpop_start timeout. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)
- Fixes body bytes encoding in curl.py. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)
- Pidbox queues work on RabbitMQ 4.x brokers that reject transient, non-exclusive queues. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)
- Redis transport now propagates polling_interval from transport_options to the Channel's _brpop_start timeout. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)
- Restores compatibility with recent gevent releases that monkey-patch the standard library queue. (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)
- When redelivering an SQS message, visibility timeout is applied based on wait_time_seconds (long polling time). (5.6.0) — [release notes](https://github.com/celery/kombu/releases/tag/v5.6.0)