# v5.0.23

## Enhancements

- [#10156](https://github.com/emqx/emqx/pull/10156) Change the priority of the configuration:
  1. If it is a new installation of EMQX, the priority of configuration is `ENV > emqx.conf > HTTP API`.
  2. If EMQX is upgraded from an old version (i.e., the cluster-override.conf file still exists in EMQX's data directory), then the configuration priority remains the same as before. That is, `HTTP API > ENV > emqx.conf`.

  Deprecated data/configs/local-override.conf.

  Stabilizing the HTTP API for hot updates.

- [#10354](https://github.com/emqx/emqx/pull/10354) More specific error messages when configure with bad max_heap_size value.
  Log current value and the max value when the `message_queue_too_long` error is thrown.

- [#10359](https://github.com/emqx/emqx/pull/10359) Metrics now are not implicitly collected in places where API handlers don't make any use of them. Instead, a separate backplane RPC gathers cluster-wide metrics.

- [#10373](https://github.com/emqx/emqx/pull/10373) Deprecate the trace.payload_encode configuration.
  Add payload_encode=[text,hidden,hex] option when creating a trace via HTTP API.

- [#10389](https://github.com/emqx/emqx/pull/10389) Unify the config formats for `cluster.core_nodes` and `cluster.statics.seeds`.
  Now they both support formats in array `["emqx1@127.0.0.1", "emqx2@127.0.0.1"]` or semicolon-separated string `"emqx1@127.0.0.1,emqx2@127.0.0.1"`.

- [#10391](https://github.com/emqx/emqx/pull/10391) Hide a large number of advanced options to simplify the configuration file.

  That includes `rewrite`, `topic_metric`, `persistent_session_store`, `overload_protection`,
  `flapping_detect`, `conn_congestion`, `stats,auto_subscribe`, `broker_perf`,
  `shared_subscription_group`, `slow_subs`, `ssl_options.user_lookup_fun` and some advance items
  in `node` and `dashboard` section, [#10358](https://github.com/emqx/emqx/pull/10358),
  [#10381](https://github.com/emqx/emqx/pull/10381), [#10385](https://github.com/emqx/emqx/pull/10385).

- [#10392](https://github.com/emqx/emqx/pull/10392) A new function to convert a formatted date to an integer timestamp has been added: date_to_unix_ts/3

- [#10404](https://github.com/emqx/emqx/pull/10404) Change the default queue mode for buffer workers to `memory_only`.
  Before this change, the default queue mode was `volatile_offload`.  When under high message rate pressure and when the resource is not keeping up with such rate, the buffer performance degraded a lot due to the constant disk operations.

- [#10426](https://github.com/emqx/emqx/pull/10426) Optimize the configuration priority mechanism to fix the issue where the configuration
  changes made to `etc/emqx.conf` do not take effect after restarting EMQX.

  More introduction about the new mechanism: [Configure Override Rules](https://www.emqx.io/docs/en/v5.0/configuration/configuration.html#configure-override-rules)

- [#10376](https://github.com/emqx/emqx/pull/10376) Simplify the configuration of the limiter feature and optimize some codes
  - Rename `message_in` to `messages`
  - Rename `bytes_in` to `bytes`
  - Use `burst` instead of `capacity`
  - Hide non-importance fields
  - Optimize limiter instances in different rate settings

- [#10430](https://github.com/emqx/emqx/pull/10430) Simplify the configuration of the `retainer` feature.
  - Mark `flow_control` as non-importance field.

## Bug Fixes

- [#10369](https://github.com/emqx/emqx/pull/10369) Fix error in `/api/v5/monitor_current` API endpoint that happens when some EMQX nodes are down.

  Prior to this fix, sometimes the request returned HTTP code 500 and the following message:
  ```
  {"code":"INTERNAL_ERROR","message":"error, badarg, [{erlang,'++',[{error,nodedown},[{node,'emqx@10.42.0.150'}]], ...
  ```

- [#10410](https://github.com/emqx/emqx/pull/10410) Fix config check failed when gateways are configured in emqx.conf.
  This issue was first introduced in v5.0.22 via [#10278](https://github.com/emqx/emqx/pull/10278), the boot-time config check was missing.