# Limitations to using the mqtt() source

Using the `mqtt()` source of AxoSyslog has the following limitations:

  * You can only use the `mqtt()` source with AxoSyslog version 3.35 or higher.
  * You cannot use the `mqtt()` source without installing the the `eclipse-paho-mqtt-c` library.
  * For more information about how you can download and install the `eclipse-paho-mqtt-c` library, see [Eclipse Paho](<https://www.eclipse.org/paho/index.php?page=clients/c/index.php>) on the Eclipse Foundation website.

  * The current implementation of the `mqtt()` source supports versions 3.1 and 3.1.1 of the MQTT protocol



Last modified April 15, 2024: [[4.7] MQTT updates and fixes (79c57cf1)](<https://github.com/axoflow/axosyslog-core-docs/commit/79c57cf1a12be4ded87c71dbf4e4fb33911cd70e>)