RabbitMQ - v3.12.3

RabbitMQ 3.12.3 is a maintenance release in the 3.12.x release series.

Please refer to the upgrade section from the 3.12.0 release notes
if upgrading from a version prior to 3.12.0.

This release requires Erlang 25 and supports Erlang versions up to 26.0.x.
RabbitMQ and Erlang/OTP Compatibility Matrix has more details on
Erlang version requirements for RabbitMQ.

Minimum Supported Erlang Version

As of 3.12.0, RabbitMQ requires Erlang 25. Nodes will fail to start on older Erlang releases.

Users upgrading from 3.11.x (or older releases) on Erlang 25 to 3.12.x on Erlang 26
(both RabbitMQ and Erlang are upgraded at the same time) must consult
the v3.12.0 release notes first.

Changes Worth Mentioning

Release notes can be found on GitHub at rabbitmq-server/release-notes.

Core Server

Bug Fixes

• Certain diagnostics operations during rolling upgrades from 3.10 to 3.11 could fail
  if the listener_records_in_ets feature flag was enabled in the middle of the upgrade.

Contributed by @gomoripeti (CloudAMQP).

GitHub issue: #8984

• On Windows, PowerShell will no longer be used as a fallback for handle.exe
  for computing how many file and socket handles a node uses.

If a user does not have handle.exe`` installed in thePATH`` of their Windows system,
a message will be logged once, and then the total handles being used will be set to 0.

PowerShell ended up being a CPU-intensive alternative that's not worth the gains
for many installations.

GitHub issue: #8700

• Node maintenance state was not replicated to all nodes, even though it was accessible
  from any node (and for any node).

GitHub issue: #9005

CLI Tools

Enhacements

• Some warnings were emitted even when --formatter was set to json.

GitHub issue: #8912

MQTT Plugin

Bug Fixes

• MQTT connections could run into an exception when a queue it consumed from was temporarily
  unavailable (e.g. was undergoing a leader election).

GitHub issue: #9040

Enhancements

• When QoS 0 consumers consistently do not keep up with publishers, some messages will be dropped
  to avoid runaway resource usage.

Now the number of dropped messages will be reflected in the dropped message metric,
together with unroutable messages.

GitHub issue: #9080

HTTP AuthN/AuthZ Backend Plugin

Bug Fixes

• AMQP 1.0 client connections were refused with this plugin.

GitHub issue: #9043

LDAP AuthN/AuthZ Backend Plugin

Bug Fixes

• AMQP 1.0 client connections were refused with this plugin.

GitHub issue: #9043

Dependency Upgrades

• osiris was upgraded to 1.6.3

Source Code Archives

To obtain source code of the entire distribution, please download the archive named rabbitmq-server-3.12.3.tar.xz
instead of the source tarball produced by GitHub.