EMQ X MQTT broker authentication plugin will throw authentication and access control event for each MQTT client to the user's own WebServer, to implement authentication and ACL.
The MQTT 5.0 protocol has made some upgrades for part of QoS packet, and the processes of dealing with packets, this article below display some simple introduction about the content of upgrades.
This article uses the practical example in `CentOS 7.2` to illustrate how to store related MQTT data through MySQL.
The message retention function of [EMQ X MQTT Broker](https://emqx.io) is implemented by the `emqx_retainer` plugin, which is enabled by default. By modifying the configuration of the` emqx_retainer` plugin, you can adjust the EMQ X Broker's retention message Location, restrict the number of retained messages and maximum payload length, and adjust the expiration time of retained messages.
The Kuiper & EdgeX integration work is almost completed, Kuiper will be integrated with EdgeX nightly Docker composer files soon. Kuiper 0.3.1will be released with EdgeX officially.
When the simultaneously existing packets in the network link exceeds the limit, that is, the Inflight Window reaches its length limit of the (see `max_inflight`), the EMQ X broker will no longer send subsequent packets, but will store these packets in the Message Queue.
MQTT Safety specifications are fully supported by EMQ, and the built-in safety functions can be used out-of-the-box without programming, which can quickly eliminate security risks in projects.
Integration with EdgeX, support for Schemaless flow definition, and FVT test case enhancement are added in this version
[MQTT X](https://mqttx.app) is a cross-platform MQTT 5.0 desktop test client provided by the world's leading open source IoT middleware provider [EMQ](https://emqx.io) , which supports macOS, Linux, Windows. The user interface of **MQTT X** simplifies the operation logic of the page with the pattern of chatting software. Users can quickly create multiple simultaneous-online MQTT clients to test the connection/publish/subscribe functions of MQTT/TCP, MQTT/TLS and other MQTT protocol features.