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HiveMQ 4.3.3 Maintenance Release

by HiveMQ Team
3 min read

The HiveMQ team is pleased to announce the availability of HiveMQ 4.3.3.

This maintenance release for the 4.3 series includes the following improvements:

  • Adjusted handling of shared subscriptions to prevent interruption of message reception to shared subscribers on a HiveMQ node when one of the shared subscribers disconnects.

  • Added message queue limit of 500,000 messages per shared subscription that provides an additional safeguard for various shared subscription scenarios.

  • Added QoS 0 message queue limit of 50 MB per shared subscription to ensure that a single shared subscription cannot occupy most of the memory.

  • Improved takeover handling when multiple concurrent connections share the same client identifier on one or more HiveMQ nodes.

  • Improved logging to provide better feedback when you use HiveMQ as a systemd service.

  • Enhanced isolation of the parameter objects that are passed to extension interceptors so that different extensions cannot interfere with each other.

  • Minor memory improvement for fan-out scenarios.

  • Security: Fixed the vulnerability of CVE-2020-13821


The improvements to the isolation of parameter objects in the HiveMQ extension system implement some new best practices for handling ByteBuffers. Please refer to our upgrade guide for more information.


The update to HiveMQ 4.3.3 also requires updates of HiveMQ extensions:


Download HiveMQ 4.3.3 now

If you currently use HiveMQ 4.x, we recommend upgrading to version 4.3.3.

Have a great day, The HiveMQ Team

HiveMQ Team

The HiveMQ team loves writing about MQTT, Sparkplug, Industrial IoT, protocols, how to deploy our platform, and more. We focus on industries ranging from energy, to transportation and logistics, to automotive manufacturing. Our experts are here to help, contact us with any questions.

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