4.0.9 release notes

(cherry picked from commit 97b98c1)

Author: michaelklishin

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+## RabbitMQ 4.0.9
+
+RabbitMQ `4.0.9` is a maintenance release in the `4.0.x` [release series](https://www.rabbitmq.com/release-information).
+
+Starting June 1st, 2024, community support for this series will only be provided to [regularly contributing users](https://github.com/rabbitmq/rabbitmq-server/blob/main/COMMUNITY_SUPPORT.md) and those
+who hold a valid [commercial support license](https://tanzu.vmware.com/rabbitmq/oss).
+
+It is **strongly recommended** that you read [4.0 release notes](https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.0.1)
+in detail if upgrading from a version prior to `4.0.0`.
+
+
+### Minimum Supported Erlang Version
+
+This release requires Erlang 26 and supports Erlang versions up to `27.3.x`.
+[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/v4.0.x/release-notes).
+
+
+### Management Plugin
+
+#### Enhancements
+
+ * It is now possible to require authentication for the HTTP API reference page
+   accessible at `/api`:
+
+   ```ini
+   management.require_auth_for_api_reference = true
+   ```
+
+   GitHub issue: [#13715](https://github.com/rabbitmq/rabbitmq-server/pull/13715)
+
+
+### Federation Plugin
+
+#### Bug Fixes
+
+ * Federation status command and HTTP API endpoint could run into an exception.
+
+   GitHub issue: [#13711](https://github.com/rabbitmq/rabbitmq-server/pull/13711)
+
+
+### AMQP 1.0 Erlang Client for RabbitMQ
+
+#### Bug Fixes
+
+ * Concurrent queue declarations could fail with an exception.
+
+   GitHub issue: [#13732](https://github.com/rabbitmq/rabbitmq-server/pull/13732)
+
+
+### Dependency Changes
+
+ * `osiris` was updated to [`1.8.7`](https://github.com/rabbitmq/osiris/releases)
+ * `khepri_mnesia_migration` was upgraded to [`0.7.2`](https://github.com/rabbitmq/khepri_mnesia_migration/releases)
+
+
+## Source Code Archives
+
+To obtain source code of the entire distribution, please download the archive named `rabbitmq-server-4.0.9.tar.xz`
+instead of the source tarball produced by GitHub.