Merge branch 'mk-4.2.2-release-notes'

(cherry picked from commit 95b544b)

Author: michaelklishin

release-notes/4.2.2.md

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+## RabbitMQ 4.2.2
+
+RabbitMQ `4.2.2` is a maintenance release in the `4.2.x` [release series](https://www.rabbitmq.com/release-information).
+
+It is **strongly recommended** that you read [4.2.0 release notes](https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.0)
+in detail if upgrading from a version prior to `4.2.0`.
+
+### Minimum Supported Erlang Version
+
+[RabbitMQ and Erlang/OTP Compatibility Matrix](https://www.rabbitmq.com/docs/which-erlang) has more details on Erlang version requirements for RabbitMQ.
+
+Nodes **will fail to start** on older Erlang releases.
+
+
+## Changes Worth Mentioning
+
+Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://github.com/rabbitmq/rabbitmq-server/tree/v4.2.x/release-notes).
+
+### Core Server
+
+#### Bug Fixes
+
+ * Fixes a binding deletion-related memory leak in Khepri.
+
+   This leak primarily affected systems with high binding churn.
+
+   GitHub issue: [#15024](https://github.com/rabbitmq/rabbitmq-server/issues/15024)
+
+ * AMQP 1.0 link error frames did not have settlement set in certain failure scenarios,
+   namely when attaching a link failed due to a missing source (queue or stream).
+
+   GitHub issue: [#15004](https://github.com/rabbitmq/rabbitmq-server/pull/15004)
+
+ * AMQP 1.0 clients that publish messages without a body now get a clearer error message.
+   Messages without a body explicitly violate the AMQP 1.0 specification.
+
+   GitHub issue: [#15048](https://github.com/rabbitmq/rabbitmq-server/pull/15048)
+
+ * Default operator policy pre-configuration in `rabbitmq.conf` were unintentionally missing a key,
+   `default_policies.operator.$id.apply_to`, for controlling what objects the policy applies to.
+
+   GitHub issue: [#14988](https://github.com/rabbitmq/rabbitmq-server/pull/14988)
+
+#### Enhancements
+
+ * Removed a cool down delay between stream chunk redelivery attempts.
+
+   GitHub issue: [#14766](https://github.com/rabbitmq/rabbitmq-server/pull/14766)
+
+ * Stream data directory can now be configured via `rabbitmq.conf`.
+
+   GitHub issue: [#15014](https://github.com/rabbitmq/rabbitmq-server/pull/15014)
+
+ * Stream replication: IP address family (IPv4 or IPv6) can now be configured via `rabbitmq.conf`.
+
+   GitHub issue: [#15012](https://github.com/rabbitmq/rabbitmq-server/pull/15012)
+
+
+### Management Plugin
+
+#### Bug Fixes
+
+ * `GET /api/deprecated-features/used` no longer returns an empty `state` field.
+
+   GitHub issue: [#14340](https://github.com/rabbitmq/rabbitmq-server/issues/14340)
+
+ * Feature flag icons now contrast well when the dark mode is used in the UI.
+
+   GitHub issue: [#14620](https://github.com/rabbitmq/rabbitmq-server/issues/14620)
+
+ * Corrected an invalid `apply_to` value (`classic_queue` instead of `classic_queues`)
+   on the policy declaration form.
+
+   Declaring a policy "directly" via the HTTP API was not affected.
+
+   GitHub issue: [#15054](https://github.com/rabbitmq/rabbitmq-server/pull/15054)
+
+#### Enhancements
+
+ * Queue declaration form fields were reordered so that the queue type dropdown comes before
+   the virtual host.
+
+   GitHub issue: [#15017](https://github.com/rabbitmq/rabbitmq-server/pull/15017)
+
+
+### Prometheus Plugin
+
+#### Enhancements
+
+ * `GET /metrics/per-object` responses on systems with thousands of objections now takes 20-30% less time.
+
+   GitHub issue: [#15035](https://github.com/rabbitmq/rabbitmq-server/pull/15035)
+
+ * Prometheus scraping endpoint responses are now streamed instead of being fully buffered before transmission.
+   This reduces memory peak footprint and improves response times for nodes with a larger number of objects.
+
+   GitHub issue: [#15018](https://github.com/rabbitmq/rabbitmq-server/pull/15018)
+
+#### Bug Fixes
+
+ * Fixed a dependency loading issue with `ddskerl` (a Prometheus library dependency)
+   that could cause `stop_app` to fail.
+
+   GitHub issue: [#15027](https://github.com/rabbitmq/rabbitmq-server/pull/15027)
+
+
+### CLI Tools
+
+#### Bug Fixes
+
+ * `rabbitmq-queues quorum_status` could run into an exception when a quorum queue member dies before recording any metrics.
+
+   GitHub issue: [#15003](https://github.com/rabbitmq/rabbitmq-server/pull/15003)
+
+
+### Web MQTT Plugin
+
+#### Bug Fixes
+
+ * The plugin now supports the `mqttv3.1` WebSocket subprotocol in addition to `mqtt`,
+   improving compatibility with older MQTT clients.
+
+   GitHub issue: [#15009](https://github.com/rabbitmq/rabbitmq-server/pull/15009)
+
+
+### AWS Peer Discovery Plugin
+
+#### Bug Fixes
+
+ * The plugin now uses IPv6 discovery endpoints in IPv6-only environments.
+
+   GitHub issue: [#14974](https://github.com/rabbitmq/rabbitmq-server/issues/14974)
+
+
+### Tracing Plugin
+
+#### Bug Fixes
+
+ * Trace files served via the management UI now include proper UTF-8 charset specification.
+
+   GitHub issue: [#14970](https://github.com/rabbitmq/rabbitmq-server/pull/14970)
+
+
+
+### Dependency Changes
+
+ * `khepri` was upgraded to [`0.17.3`](https://github.com/rabbitmq/khepri/releases/tag/v0.17.3)
+ * `seshat` was upgraded to [`1.0.1`](https://github.com/rabbitmq/seshat/releases/tag/v1.0.1)