What's New in RabbitMQ 4.0
RabbitMQ 3.13 is a new release branch published on 18 Sep 2024. RabbitMQ 4.0.3 is the latest patch release for this release branch. See the Release Information section to learn more about all patch releases for this release branch.
AMQP 1.0 becomes a core protocol
AMQP 1.0 is now a core protocol that is always enabled. Its plugin is now a no-op that only exists to simplify upgrades.
The AMQP 1.0 implementation is also significantly more efficient: its peak throughput is more than double than that of 3.13.x
Khepri now fully supported
Khepri is a new backend for RabbitMQ’s metadata store. It was introduced as an experiment in RabbitMQ 3.13.0. It is now much more stable and efficient. That’s why it is now fully supported in the case of an issue. It will not be a blocker either to upgrade RabbitMQ in the future (unlike an upgrade from RabbitMQ 3.13.x to 4.0.x with Khepri enabled which is unsupported).
Users are encouraged to try it in their test environment with workloads as close as possible to the production before enabling it in production.
Everything around Khepri is documented in the new Metadata store section.
Classic queue mirroring is removed
After three years of deprecation, classic queue mirroring was completely removed in this version. Quorum queues and streams are two mature replicated data types offered by RabbitMQ 4.x. Classic queues continue being supported without any breaking changes for client libraries and applications but they are now a non-replicated queue type.