## RabbitMQ 4.3.0

RabbitMQ `4.3.0` is a new feature release.


## Breaking Changes and Compatibility Notes

### Mnesia and Parition Handling Strategies are Removed

Since only `4.2.x` clusters can upgrade to `4.3.0` [in place](https://www.rabbitmq.com/docs/upgrade), this
won't be a breaking change for nearly all instalations but it will affect community
plugins that use Mnesia.

All partition handling-related keys in `rabbitmq.conf` will be
accepted by `4.3.0` nodes but won't have any effect:

 * `cluster_partition_handling`
 * `cluster_partition_handling.pause_if_all_down.recover`
 * `cluster_partition_handling.pause_if_all_down.nodes.$name`

Team RabbitMQ recommends removing the above keys from `rabbitmq.conf` before or shortly after upgrading.

### Deprecated Features are Now Disabled by Default

A number of [deprecated features](https://www.rabbitmq.com/docs/deprecated-features) are now disabled
by default and require the user to opt-in in order to use them.

This includes [non-durable (transient) non-exclusive](https://www.rabbitmq.com/docs/queues) queues:
attempts to declare a queue with such property combination will be rejected by default.
Use durable queues, transient exclusive queues, or durable queues with a [queue TTL](https://www.rabbitmq.com/docs/ttl#queue-ttl) instead.

To explicitly allow transient non-exclusive queues, make sure that
**all nodes in the cluster** include the following `rabbitmq.conf` key
and were restarted so that all nodes have a consistent view of the deprecated
feature settings:

```ini
# Enables deprecated non-durable (transient) non-exclusive queues
# (disabled by default as of RabbitMQ `4.3.0`, will be removed in a later version).
#
# Must be effective on all cluster nodes BEFORE
# the cluster is upgraded to `4.3.0`.
# If only some nodes have the setting configured, it will not have the desired effect.
deprecated_features.permit.transient_nonexcl_queues = true
```

If only some nodes have setting configured, it will not have the desired effect.

### Classic Queues v1 Storage (CQv1) is Removed

This release removes the original classic queue storage implementation these days
known as CQv1. A 2nd generation implementation called CQv2 has been adopted
as the default starting with `4.2.0`.

This means that attempts to declare a queue using the following [optional queue arguments](https://www.rabbitmq.com/docs/queues#optional-arguments) will fail:

 * `x-queue-mode` set to any value
 * `x-queue-version` set to `1`

Existing classic queues upgraded to CQv2 during an earlier upgrade to `4.2.x` will continue
operating as usual.

### Consumer Timeouts are No Longer Evaluated for Classic Queues and Streams

This release moves consumer timeout handling responsibility into the queues
themselves. Also, all protocols (except for the stream protocol) now evaluate
consumer timeout for queue types that support them. Classic queues and streams
never evaluate consumer timeouts as their use cases largely avoid the need for
such as feature.

### `rabbitmqadmin` v1 Download Endpoint is Removed

Environments that still rely on `rabbitmqadmin` v1 have two migration options:

 * Move to [`rabbitmqadmin` v2](https://www.rabbitmq.com/docs/management-cli)
 * Switch to downloading `rabbitmqadmin` v1 [from the `v4.2.x` branch](https://raw.githubusercontent.com/rabbitmq/rabbitmq-server/refs/heads/v4.2.x/deps/rabbitmq_management/bin/rabbitmqadmin) on GitHub


## Release Highlights

### Khepri is Now The Only Metadata Store

As of this release, Khepri is the only [metadata store](https://www.rabbitmq.com/docs/metadata-store) supported
by RabbitMQ: Mnesia was removed completely.

In practical operational terms, this means that

1. For a cluster to be available, a majority of nodes must be online at all times
2. Failure and partition recovery in a RabbitMQ cluster is now significantly
   simpler and uniform: all components that have replicated state (Khepri, quorum queues, streams)
   recover per Raft recovery semantics

### Quorum Queues Enhancements

This release upgrades the [Ra](https://github.com/rabbitmq/ra) dependency to `3.x` and introduces
a new (8th) version of the quorum queue state machine with several new features and optimisations:

 * **Strict priority queues** with per-priority message counts, correct
   redelivery ordering, and priority-aware message expiration
 * **Delayed retry** for quorum queues: configurable increasing backoff when
   messages are returned
 * **Consumer timeout** for quorum queues: configurable timeout for
   unacknowledged messages, with protocol-specific handling for AMQP 1.0 and
   MQTT
 * **Recovery snapshots** and **snapshot throttling** to reduce recovery time
   and improve snapshotting decisions
 * **Memory optimisations** including compact message references, optimised
   tuple storage for delayed keys, and removal of `rabbit_fifo_index` usage


## Upgrading to 4.3.0

### Documentation Guides on Upgrades

See the [Upgrading guide](https://www.rabbitmq.com/docs/upgrade) for documentation on upgrades and [GitHub releases](https://github.com/rabbitmq/rabbitmq-server/releases)
for release notes of individual releases.

This release series supports upgrades from `4.2.x`. Upgrades from earlier series are **not** supported:
users must upgrade to the latest available `4.2.x` patch release before upgrading to `4.3.0`.


### New Required Feature Flags

All feature flags introduced in `4.2.0` and earlier are required, including the following:

 * `rabbitmq_4.2.0`
 * `rabbitmq_4.1.0`
 * `rabbitmq_4.0.0`
 * `khepri_db`
 * `quorum_queue_non_voters`
 * `message_containers_deaths_v2`

Enable all required feature flags before upgrading to `4.3.0`.

If your RabbitMQ cluster had plugin `rabbitmq_amqp1_0` enabled in RabbitMQ `3.13.x` (and your cluster still serves AMQP 1.0 client connections in `4.x`), your cluster should do at least one rolling update **after** enabling feature flag `rabbitmq_4.0.0` but **before** upgrading to `4.3.0`.

### Deprecated Features

In `4.3.0` the [deprecation phase](https://www.rabbitmq.com/docs/deprecated-features) of the following features advanced from `permitted_by_default` to `denied_by_default`:

 * `amqp_address_v1`
 * `amqp_filter_set_bug`
 * `global_qos`
 * `queue_master_locator`
 * `transient_nonexcl_queues`

And the deprecated feature `ram_node_type` has been removed.

### Mixed Version Cluster Compatibility

RabbitMQ 4.3.0 nodes can run alongside `4.2.x` in the same cluster.

Mixed version clusters are a mechanism that allows rolling upgrades and are not meant to be run for extended
periods of time (no more than a few hours).

### Recommended Post-upgrade Procedures

This version does not require any additional post-upgrade procedures
compared to other versions.


## Changes Worth Mentioning

### Core Server

#### Enhancements

 * When a message is rejected by a queue, RabbitMQ now provides the queue name and rejection reason to AMQP 1.0 publishers
   in the `Rejected` outcome. This is particularly useful when multiple queues are bound to an exchange, as it allows
   publishers to identify which specific queue out of several target queues rejected the message and why
   (e.g., maximum queue length reached or queue unavailable). Previously, publishers had no way to determine which queue
   rejected their message or the reason for rejection.

   The queue name and reason are included in the `info` field of the `Rejected` outcome's `error` field:
   * `queue: <queue name>`
   * `reason: maxlen | unavailable`

   GitHub issue: [#15075](https://github.com/rabbitmq/rabbitmq-server/pull/15075)

 * Quorum queues now support **strict priority queues** with per-priority message counts,
   correct redelivery ordering across priorities, and priority-aware message expiration scans.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * Quorum queues now support **delayed retry** with configurable backoff based on delivery count. When messages
   are returned (via reject, nack, or modify), they can be held in a delayed state before becoming
   available again. The delay is based on delivery count: `min(min_delay * delivery_count, max_delay)`.

   Configuration is available via queue arguments (`x-delayed-retry-type`, `x-delayed-retry-min`,
   `x-delayed-retry-max`) or policy keys (`delayed-retry-type`, `delayed-retry-min`,
   `delayed-retry-max`). The retry type can be set to `disabled`, `all`, `failed`, or `returned`.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * Quorum queues now support a configurable **consumer timeout**. When a consumer holds unacknowledged
   messages beyond the timeout, the messages are returned to the queue. For AMQP 1.0 clients,
   timed-out deliveries are released via `DISPOSITION(state=released)` instead of detaching the link,
   allowing the consumer to recover without re-attaching. MQTT consumers are also supported.

   The timeout can be set via the `x-consumer-timeout` consumer argument, queue argument, `consumer-timeout`
   policy key, or the global `consumer_timeout` setting in `rabbitmq.conf`.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * A new `consumer_disconnected_timeout` setting controls how long quorum queues wait before returning
   messages when a consumer's node becomes unreachable due to a network partition. The default is 60 seconds.
   Configurable via `consumer_disconnected_timeout` in `rabbitmq.conf`, the `consumer-disconnected-timeout`
   policy key, or the `x-consumer-disconnected-timeout` queue argument.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * Quorum queue **recovery snapshots** reduce recovery time after a member restart by avoiding
   the need to replay all enqueue commands from the log.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * Quorum queue **snapshot throttling** now uses WAL fill ratio and reclaimable byte tracking
   to make smarter snapshotting decisions, yielding roughly one snapshot per queue per WAL cycle
   instead of excessive snapshots in shallow, fast-flowing queues.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * Quorum queue **memory optimisations**: message references now use a compact packed integer
   representation ("compact" means up to 59-bit) when possible, **halving per-message
   memory overhead** in many scenarios. The `rabbit_fifo_index` module is no longer used by the
   main state machine.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * Quorum queues now allow unlimited explicit message returns. The delivery limit is based on
   `delivery-count` rather than `acquired-count`, so messages can be explicitly returned to the
   queue without counting towards the delivery limit.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * The `x-modulus-hash` exchange type, previously provided by the sharding plugin, was moved
   into the core and reworked to provide stable message routing (distribution)
   assuming a stable set of bindings, including between node restarts.

   GitHub issue: [#15849](https://github.com/rabbitmq/rabbitmq-server/pull/15849)

 * When quorum queue members (replicas) are deleted from a node, either manually
   via `rabbitmq-queues shrink` or as part of `rabbitmqctl forget_cluster_node`,
   the members are stopped in parallel.

   GitHub issue: [#15081](https://github.com/rabbitmq/rabbitmq-server/pull/15081)

 * Purging a quorum queue now also removes at-least-once dead-lettered messages that were pending delivery.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * AMQP 0-9-1: when a connection's credentials are refreshed, the permissions cache is now
   cleared and consumer permissions are re-validated immediately

   GitHub issue: [#16092](https://github.com/rabbitmq/rabbitmq-server/pull/16092)

 * Quorum queue delivery limit can now be changed via policy without queue redeclaration

   GitHub issue: [#16035](https://github.com/rabbitmq/rabbitmq-server/pull/16035)

 * Khepri topic exchange routing projection (v4): replaced the internal representation with a trie
   backed by an `ordered_set` ETS table, significantly improving routing performance
   for topic exchanges with many bindings

   GitHub issue: [#15619](https://github.com/rabbitmq/rabbitmq-server/pull/15619)

 * Quorum queues notify AMQP 1.0 clients of Single Active Consumer state changes

   GitHub issue: [#15736](https://github.com/rabbitmq/rabbitmq-server/pull/15736)

 * More `rabbitmq.conf` keys now accept tagged values (e.g., `encrypted:...`)

   GitHub issue: [#15808](https://github.com/rabbitmq/rabbitmq-server/pull/15808)

 * Startup banner no longer includes the Erlang cookie hash

   GitHub issue: [#16087](https://github.com/rabbitmq/rabbitmq-server/pull/16087)

 * Optimised AMQP 1.0 message container annotation handling during modify outcomes

   GitHub issue: [#15743](https://github.com/rabbitmq/rabbitmq-server/pull/15743)

 * Bulk queue delete with Khepri has been optimized

   GitHub issue: [#14902](https://github.com/rabbitmq/rabbitmq-server/pull/14902)

 * Optimised quorum queue message expiry scanning

   GitHub issue: [#15846](https://github.com/rabbitmq/rabbitmq-server/pull/15846)

 * AMQP 0-9-1: `configure` permission checks now apply to passive queue and exchange declarations,
   matching the behavior of their regular counterparts

   GitHub issue: [#16085](https://github.com/rabbitmq/rabbitmq-server/pull/16085)

 * Khepri snapshot interval is now configurable in `rabbitmq.conf`

   GitHub issue: [#16011](https://github.com/rabbitmq/rabbitmq-server/pull/16011)

 * Quorum queue Raft settings: additional configuration settings are now exposed in `rabbitmq.conf`,
   including maximum segment size

   GitHub issue: [#15962](https://github.com/rabbitmq/rabbitmq-server/pull/15962)


#### Bug Fixes

 * If a quorum queue with a large backlog terminated abnormally, node memory
   footprint could spike.

   GitHub issue: [#15837](https://github.com/rabbitmq/rabbitmq-server/pull/15837)

 * `rabbitmqctl forget_cluster_node` now removes all quorum queue and stream members (replicas)
   before proceeding to leave the metadata store cluster.

   This order minimizes the risk of some replicas being left behind on the leaving node.

   GitHub issue: [#15729](https://github.com/rabbitmq/rabbitmq-server/pull/15729)

 * Quorum queue at-most-once dead lettering for the overflow behaviour `drop-head` now happens in the correct order.

   GitHub issue: [#14926](https://github.com/rabbitmq/rabbitmq-server/pull/14926)

 * Feature flag state in the registry and on disk were not consistent for a period of time during node boot.

   GitHub issue: [#14943](https://github.com/rabbitmq/rabbitmq-server/pull/14943)

 * Classic queues now implement AMQP 1.0 delivery-count and first-acquirer headers properly.

   GitHub issue: [#15020](https://github.com/rabbitmq/rabbitmq-server/pull/15020)

 * Quorum queues returned an incorrect consumer count in the response to a passive
   `queue.declare` operation

   GitHub issue: [#16185](https://github.com/rabbitmq/rabbitmq-server/pull/16185)

 * Classic queue shared store could leave stale index entries after segment removal or rollover,
   causing unnecessary disk space usage

   GitHub issue: [#16142](https://github.com/rabbitmq/rabbitmq-server/pull/16142)

 * Bindings targeting [Direct Reply-to](https://www.rabbitmq.com/docs/direct-reply-to) pseudo-queues are now rejected instead of
   being silently accepted without any functional effect

   GitHub issue: [#15935](https://github.com/rabbitmq/rabbitmq-server/pull/15935)

 * AMQP 1.0 sessions could grant too many credits in certain failure and recovery scenarios

   GitHub issue: [#15883](https://github.com/rabbitmq/rabbitmq-server/pull/15883)

 * Quorum queues: `acquired-count` is now correctly preserved when dead-lettering

   GitHub issue: [#16039](https://github.com/rabbitmq/rabbitmq-server/pull/16039)

 * AMQP 1.0: attaching with a link handle already in use on the same session is now rejected
   with a `handle-in-use` session error, as required by the specification

   GitHub issue: [#16039](https://github.com/rabbitmq/rabbitmq-server/pull/16039)

 * Quorum queues: Single Active Consumer could incorrectly report multiple active consumers
   in certain timing scenarios

   GitHub issue: [#15733](https://github.com/rabbitmq/rabbitmq-server/pull/15733)

 * Quorum queues: consumer timeout could fail to trigger under certain conditions

   GitHub issue: [#15805](https://github.com/rabbitmq/rabbitmq-server/pull/15805)

 * The channel limit exceeded error message now correctly identifies the per-user limit
   as the source of the constraint

   GitHub issue: [#15750](https://github.com/rabbitmq/rabbitmq-server/pull/15750)


### Stream Plugin

#### Bug Fixes

 * `stream.read_ahead` is a new setting that controls how much data is prefetched from disk
   for stream reads (consumption).

   GitHub issue: [#14948](https://github.com/rabbitmq/rabbitmq-server/pull/14948)

 * Stream deletion is now more resilient and can handle certain mid-deletion failure scenarios.

   GitHub issue: [#14852](https://github.com/rabbitmq/rabbitmq-server/issues/14852)

 * `new_stream` coordinator command is now idempotent. Previously, concurrent or retried
   stream declarations could produce spurious errors even though the stream was created
   successfully

   GitHub issue: [#15706](https://github.com/rabbitmq/rabbitmq-server/pull/15706)


### Prometheus Plugin

#### Enhancements

 * `/metrics/detailed` endpoint now supports filtering queue metrics by queue name

   GitHub issue: [#15689](https://github.com/rabbitmq/rabbitmq-server/pull/15689)


### Grafana Dashboards

#### Enhancements

 * The [dashboards](https://grafana.com/orgs/rabbitmq) were updated for the most recent RabbitMQ release series.

 * Replaced explicit rate intervals with `$__rate_interval` for better
   compatibility across different scrape intervals

   GitHub issue: [#15978](https://github.com/rabbitmq/rabbitmq-server/pull/15978)


### Management Plugin

#### Enhancements

 * `GET /api/queues/{vhost}` requests no longer perform unnecessary virtual host permission checks
   and log less (at `debug` level) as a result.

   GitHub issue: [#14923](https://github.com/rabbitmq/rabbitmq-server/discussions/14923)

 * Quorum queue delayed retry configuration and status, per-priority message counts, and consumer
   timeout state are now displayed in the management UI.

   GitHub issue: [#13885](https://github.com/rabbitmq/rabbitmq-server/pull/13885)

 * `GET /users/{user}/queues` has been added.

   GitHub issue: [#15074](https://github.com/rabbitmq/rabbitmq-server/pull/15074)

 * HTTP API displays static connection info (peer address, TLS details, auth mechanism)
   even when stats collection is disabled via `rabbitmq.conf`

   GitHub issue: [#16009](https://github.com/rabbitmq/rabbitmq-server/pull/16009)

#### Bug Fixes

 * `effective_policy_definition` in HTTP API responses now returns an empty JSON object
   (not an array or empty string) when no policy applies to a queue

   GitHub issue: [#16017](https://github.com/rabbitmq/rabbitmq-server/pull/16017)

 * Management UI: OAuth 2 used side by side with Basic Auth could fail to reload provider
   configuration correctly

   GitHub issue: [#15793](https://github.com/rabbitmq/rabbitmq-server/pull/15793)

 * Management UI: preference cookie expiry now respects the configured session timeout
   setting rather than using a hardcoded value

   GitHub issue: [#15814](https://github.com/rabbitmq/rabbitmq-server/pull/15814)

 * Management UI: users were presented with a 401 error after changing their own password
   via the UI. The session is now refreshed automatically

   GitHub issue: [#15730](https://github.com/rabbitmq/rabbitmq-server/pull/15730)

 * The deprecated, unused `GET /api/auth` endpoint was removed.

   It has been out of use since 3.11 but never removed.

   GitHub issue: [#16083](https://github.com/rabbitmq/rabbitmq-server/pull/16083)

 * `POST /api/users/bulk-delete` now respects the `protected_users` configuration,
   matching the behavior of the single-user `DELETE /api/users/:name` endpoint

   GitHub issue: [#16143](https://github.com/rabbitmq/rabbitmq-server/pull/16143)


### MQTT Plugin

#### Enhancements

 * For MQTT 5.0 publishers, when a message is rejected because the target queue's maximum length is exceeded,
   RabbitMQ now returns a `Quota exceeded` reason code in the PUBACK packet. This provides publishers with
   actionable information about why their message was rejected.

   GitHub issue: [#15075](https://github.com/rabbitmq/rabbitmq-server/pull/15075)

 * MQTT QoS 0 queue type now reports member information in management API responses

   GitHub issue: [#15656](https://github.com/rabbitmq/rabbitmq-server/pull/15656)


### Web MQTT Plugin

#### Enhancements

 * A default `max_frame_size` is now set on WebSocket connections, bounding decompressed frame sizes.
   The limit starts at `mqtt.max_packet_size_unauthenticated` and is raised after successful CONNECT

   GitHub issue: [#16180](https://github.com/rabbitmq/rabbitmq-server/pull/16180)

 * A `login_timeout` is now enforced for WebSocket connections, matching the TCP listener behavior

   GitHub issue: [#16120](https://github.com/rabbitmq/rabbitmq-server/pull/16120)

 * WebSocket Origin header will be validated `web_mqtt.allow_origins`

   GitHub issue: [#16158](https://github.com/rabbitmq/rabbitmq-server/pull/16158)


### STOMP Plugin

#### Enhancements

 * For certain destinations that previously used non-durable (transient) queues,
   STOMP subscriptions now use exclusive queues, as non-exclusive transient queues
   are a deprecated property combination disabled by default as of this release

   GitHub issue: [#13016](https://github.com/rabbitmq/rabbitmq-server/pull/13016)


### Web STOMP Plugin

#### Enhancements

 * WebSocket Origin header validation is now available via `web_stomp.allow_origins`

   GitHub issue: [#16158](https://github.com/rabbitmq/rabbitmq-server/pull/16158)


### Federation Plugin

#### Enhancements

 * Federation links and their connections are now stopped in parallel.

   This significantly improves shutdown time for nodes with many (into thousands) federation links.

   GitHub issue: [#15271](https://github.com/rabbitmq/rabbitmq-server/pull/15271)

 * Federation links no longer restart during plugin or node shutdown.

   For nodes with hundreds or thousands of federation links, link recovery could
   significantly delay node shutdown.

   GitHub issue: [#15258](https://github.com/rabbitmq/rabbitmq-server/pull/15258)


### Federation Management Plugin

#### Bug Fixes

 * Federation link restart operations now require the `policymaker` tag

   GitHub issue: [#16051](https://github.com/rabbitmq/rabbitmq-server/pull/16051)


### Shovel Plugin

#### Enhancements

 * An optional `src-consumer-name` property can be specified to define the consumer tag
   (`amqp091` and `local` `src-protocol`) or link identifier (`amqp10` protocol)

#### Bug Fixes

 * Improved target node resource alarm handling for AMQP 1.0 and local shovels.

   GitHub issue: [#14886](https://github.com/rabbitmq/rabbitmq-server/pull/14886)

 * Local shovels could run into an exception that would cause a shovel restart.

   GitHub issue: [#14872](https://github.com/rabbitmq/rabbitmq-server/pull/14872)

 * AMQP 1.0 shovels ignored the `sasl` URI parameter.

   GitHub issue: [#14867](https://github.com/rabbitmq/rabbitmq-server/pull/14867)


### Shovel Management Plugin

#### Bug Fixes

 * Shovel management: DELETE operations now require the `policymaker` tag, matching the
   federation plugin counterpart

   GitHub issue: [#16051](https://github.com/rabbitmq/rabbitmq-server/pull/16051)


### OAuth 2 Plugin

#### Bug Fixes

 * A usability improvement allows the plugin to automatically load the trusted system x.509 (TLS) certificates.

   GitHub issue: [#14927](https://github.com/rabbitmq/rabbitmq-server/pull/14927)

 * The auth cache backend now correctly delegates token expiry timestamps to the wrapped backend,
   ensuring connections are closed when tokens expire

   GitHub issue: [#16100](https://github.com/rabbitmq/rabbitmq-server/pull/16100)


### LDAP Plugin

#### Enhancements

 * LDAP queries, including multi-line ones, can now be specified in `rabbitmq.conf`.

   GitHub issue: [#14868](https://github.com/rabbitmq/rabbitmq-server/pull/14868)

#### Bug Fixes

 * A usability improvement allows the plugin to automatically load the trusted system certificates
   when the user only enables TLS for the LDAP client but does not configure any other settings.

   GitHub issue: [#14937](https://github.com/rabbitmq/rabbitmq-server/pull/14937)

 * DN values are now handled per RFC 4514

   GitHub issue: [#16101](https://github.com/rabbitmq/rabbitmq-server/pull/16101)


### HTTP Auth Backend Plugin

#### Enhancements

 * The HTTP Auth Backend can now optionally provide a custom authorization denial reason to AMQP clients.

   To opt in, return `deny <Reason>` (instead of only `deny`) in the HTTP response body of your HTTP auth backend and set the following in your `rabbitmq.conf` file:

```ini
auth_http.authorization_failure_disclosure = true
```

   See the [README](https://github.com/rabbitmq/rabbitmq-server/blob/main/deps/rabbitmq_auth_backend_http/README.md) for more information.

   GitHub issue: [#14641](https://github.com/rabbitmq/rabbitmq-server/pull/14641)


### Sharding Plugin

#### Enhancements

 * The `x-modulus-hash` exchange type, previously provided by the sharding plugin, was moved
   into the core and reworked to provide stable message routing (distribution)
   assuming a stable set of bindings, including between node restarts.

   GitHub issue: [#15849](https://github.com/rabbitmq/rabbitmq-server/pull/15849)



### Trust Store Plugin

#### Enhancements

 * Refactored certificate identification to avoid (unlikely) conflicts

   GitHub issue: [#16116](https://github.com/rabbitmq/rabbitmq-server/pull/16116)

 * The plugin now provides CLI commands for trust store certificate management have been introduced

   GitHub issue: [#15746](https://github.com/rabbitmq/rabbitmq-server/pull/15746)

 * Rejected certificates are now logged with additional diagnostic details

   GitHub issue: [#15889](https://github.com/rabbitmq/rabbitmq-server/pull/15889)


### Tracing Plugin

#### Bug Fixes

 * Trace file downloads now set the charset to UTF-8 when serving trace files.

   GitHub issue: [#13952](https://github.com/rabbitmq/rabbitmq-server/issues/13952)


### Dependency Changes

 * `ra` was upgraded to [`3.1.6`](https://github.com/rabbitmq/ra/releases/tag/v3.1.6)
 * `khepri` was upgraded to [`0.18.0`](https://github.com/rabbitmq/khepri/releases)
 * `osiris` was upgraded to [`1.3.1`](https://github.com/rabbitmq/osiris/releases)
 * `gen_batch_server` was upgraded to [`0.9.2`](https://github.com/rabbitmq/gen-batch-server/releases)
 * `cuttlefish` was upgraded to [`3.6.0`](https://github.com/kyorai/cuttlefish/releases)

## Source Code Archives

To obtain source code of the entire distribution, please download the archive named `rabbitmq-server-4.3.0.tar.xz`
instead of the source tarball produced by GitHub.
