# MQTTX 1.13.3: Security Improvements and CLI Updates

> MQTTX 1.13.3 brings security improvements, a new CLI update command, and benchmark bug fixes and optimizations.

> Language: en · Published: 2026-11-04 · Category: Release Notes · Version: 1.13.3 · Canonical: https://mqttx.app/blog/mqttx-1-13-3-released · Translation: [中文](https://mqttx.app/zh/blog/mqttx-1-13-3-released.md)

MQTTX 1.13.3 focuses on security improvements, a new CLI update command, and benchmark bug fixes and optimizations. It also expands Desktop Last-Will payload formats and improves everyday Agent interactions.

## Security improvements

This release strengthens Desktop and Agent security across operation approvals, script execution, content handling, and update downloads.

- Tighten approval requirements for delete, clear, and script changes.
- Improve script execution and reply rendering, and use more secure storage for API keys.
- Verify CLI downloads and strengthen security in the Desktop update window.

## Update MQTTX CLI from the terminal

Updating a standalone CLI installation previously meant downloading and replacing the executable. Starting with 1.13.3, you can run:

```bash
mqttx update
```

The command checks for a newer release and updates through the appropriate channel. Standalone binaries download and replace the current executable; npm and Homebrew installations invoke their package manager. Run `mqttx --version` afterward to check the installed version.

> The update command is available from 1.13.3. Users on older versions need to upgrade once through their existing installation channel.

## More accurate benchmarks and connection recovery

CLI publish and subscribe benchmarks now calculate rates using the actual sampling interval. Workloads start correctly when an initial connection succeeds after a retry, and active connection counts update correctly. This release also fixes split-file replay stalling after a disconnect.

Fixed `%c` in publish topic templates to use each connection’s actual ClientId.

> Topics containing `%c` may change after upgrading; check subscriptions that depend on the previous topics.

## Choose a Last-Will payload format

> Contributed by [Killian0812](https://github.com/Killian0812).

A Last-Will message lets the broker publish a predefined message when a client disconnects unexpectedly. If a device expects a binary format, its Last-Will payload needs the same encoding.

Desktop now supports **Plaintext, JSON, Base64, Hex, CBOR, and MsgPack** for Last-Will payloads. Open **Last Will and Testament** in the connection settings, enter the topic, QoS, retain setting, and payload, then choose a format from the bottom-right corner of the editor.

![Last-Will payload format selection](https://mqttx.app/images/blog/mqttx-1-13-3/mqttx-1.13.3-last-will-formats.png)

_The Last-Will editor offers six payload formats._

For example, select MsgPack and enter a JSON object:

```json
{
  "msg": "CLOSED!"
}
```

MQTTX encodes the Last-Will message as MsgPack, so you do not need a separate tool to prepare the binary content. The format is saved with the connection. Existing connections continue to use Plaintext by default.

## Agent improvements for everyday work

Agent approval cards show more complete operation parameters, including timed-publish intervals, so you can check them before execution.

This release also improves reply rendering, MCP tool-name handling, and Desktop startup compatibility. Other fixes correct Last-Will topics in connection history and Hex payload encoding when input includes tabs or line breaks.

## Download and share feedback

Visit the [MQTTX download page](https://mqttx.app/downloads) to choose Desktop, CLI, or Web. See the [v1.13.3 release](https://github.com/emqx/MQTTX/releases/tag/v1.13.3) for the complete changes, and report issues on [GitHub](https://github.com/emqx/MQTTX/issues).

Thank you to everyone who shared feedback, tested changes, and contributed to this release. Special thanks to [Killian0812](https://github.com/Killian0812) for contributing Last-Will payload format support.