# Incompatible Changes in EMQX 5.9

## 5.9.2

- [#15753](https://github.com/emqx/emqx/pull/15753) Listener connection rate limits (`max_conn_rate` and `max_conn_burst`) are now enforced per listener rather than per acceptor, restoring the behavior before 5.9.0.

  As a result, configurations from versions 5.9.0 and 5.9.1 are incompatible: the specified rate values must be scaled up by the number of acceptors configured for each listener to preserve the same effective limits.

- [#16062](https://github.com/emqx/emqx/pull/16062) Fixed an issue where RocketMQ actions ignored the configured payload template and sent the entire rule output instead.

  If you relied on the previous (incorrect) behavior, you may need to update your payload templates to ensure messages are formatted as expected.

- [#16284](https://github.com/emqx/emqx/pull/16284) Stopped releasing packages for macOS 13 and CentOS 7.


## 5.9.1

- [#15156](https://github.com/emqx/emqx/pull/15156) Added strict schema validation for the `dashboard.sso.oidc.issuer` field. This field must now contain a valid URL. Previously, invalid configurations could be accepted by the API without errors but would cause EMQX to fail to restart, potentially resulting in a crash (`erl_crash.dump`).

## 5.9.0

- [#14865](https://github.com/emqx/emqx/pull/14865) Dropped old LDAP authentication config layout (deprecated since v5.4).
  Move `password_attribute` and `is_superuser_attribute` under the `method` block:
    ```hcl
    method {
      type = hash
      password_attribute = "userPassword"
      is_superuser_attribute = "isSuperuser"
    }
    ```

- [#14765](https://github.com/emqx/emqx/pull/14765) Added extra validation for using Named Instances in SQL Server Connector.  Previously, we could not infer when the user furnished an explicit port for SQL Server, and always added the default port if not explicitly defined.

  For Named Instances, we need to explicitly define a port to connect to when connecting with the ODBC driver. And the driver happily connects to whatever instance is running on that port, completely ignoring the given Instance Name, if any.

  Now, we impose that the port is to be explicitly defined when an instance name is given, and we also attempt to infer differences between desired and connected instance names during health checks.

- [#14773](https://github.com/emqx/emqx/pull/14773) Rate limiting configuration options have been changed.
  - This change is incompatible with versions prior to 5.1.0
  - This change is also incompatible with manually modified limiter configurations that use structures from versions prior to 5.1.0
  - The undocumented endpoint `/configs/limiter` has been removed
  
- [#14703](https://github.com/emqx/emqx/pull/14703) Changed the maximum allowed value for `force_shutdown.max_heap_size` to `128GB`.

- [#14957](https://github.com/emqx/emqx/pull/14957) The way plugin configurations are updated has changed. The system now respects the result of the `on_config_changed` callback when updating a plugin's configuration. This change only affects new configuration updates made through the Dashboard. The result of the `on_config_changed` callback is still ignored for configurations that have already been stored in the cluster.

  Additionally, plugin apps are now loaded during plugin installation to ensure the `on_config_changed` callback is called even for stopped plugins.