# v5.1.6

## Enhancements

- [#11429](https://github.com/emqx/emqx/pull/11429) Added option to configure detection of legacy protocol in MondoDB connectors and bridges.

- [#11436](https://github.com/emqx/emqx/pull/11436) Add a new API endpoint `DELETE  /banned` to clear all `banned` data.

- [#11438](https://github.com/emqx/emqx/pull/11438) Changed the type of the `mqtt.mqx_packet_size` from string to byteSize to better represent the valid numeric range.
  Strings will still be accepted for backwards compatibility.

- [#11446](https://github.com/emqx/emqx/pull/11446) Refactored datetime-related modules and functions to simplify the code.

- [#11396](https://github.com/emqx/emqx/pull/11396) Introduce topic index for the rule engine runtime that significantly improves the performance of EMQX with a non-trivial number of rules consuming messages matching different topic filters.

## Bug Fixes

- [#11424](https://github.com/emqx/emqx/pull/11424) Add a check for the maximum value of the timestamp in the API to ensure it is a valid Unix timestamp.

- [#11445](https://github.com/emqx/emqx/pull/11445) Removed os_mon application monitor support on Windows platforms to prevent VM crashes.
  Functionality remains on non-Windows platforms.

- [#11454](https://github.com/emqx/emqx/pull/11454) Fixed crashing when debugging/tracing with large payloads(introduce when [#11279](https://github.com/emqx/emqx/pull/11279))

- [#11456](https://github.com/emqx/emqx/pull/11456) Removed validation that enforced non-empty PEM for CA cert file.
  CA certificate file PEM can now be empty.

- [#11499](https://github.com/emqx/emqx/pull/11499) Upgrade Erlang/OTP to 25.3.2-2

  Erlang/OTP 25.3.2-2 excludes sensitive data from mnesia_hook log message.