HiveMQ 4.9.4 Maintenance Release

HiveMQ 4.9.4 Maintenance Release

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Written by The HiveMQ Team

Category: HiveMQ Release

Published: February 7, 2023

The HiveMQ team is pleased to announce the availability of HiveMQ 4.9.4.

This maintenance release for the 4.9 series includes the following improvements:

HiveMQ Enterprise MQTT Broker

  • Improved performance for use cases that have a large number of subscribers for the same shared subscription group.
  • Improved sustained message rates for clusters with a large number of nodes and CPU cores.
  • Increased message throughput rates and payload cleanup performance in deployments with a large number of CPU cores.
  • Improved handling in the cleanup service to fix an issue that could cause a periodic cleanup task to get stuck.
  • Optimized caching to eliminate unnecessary Java heap memory consumption.
  • Fixed an issue that could result in outdated data not being fully removed when a node joins a cluster.
  • Fixed an issue that prevented the correct display of persistence executor metrics for retained message tasks and subscription tasks.
  • Improved HiveMQ event log feedback for failed authentication to include custom reason strings from extensions.
  • Fixed an issue that could cause the incorrect display of menu items in the HiveMQ Control Center main navigation after a license change.

HiveMQ Enterprise Extension for Kafka

  • Added tracing support in the HiveMQ Enterprise Extension for Kafka for MqttToKafkaTransformer customizations that create multiple Kafka records from a single MQTT message.
  • Fixed an issue where the HiveMQ Enterprise Extension for Kafka ignored the keystore private key password value in the TLS configuration to a Confluent Schema Registry. The extension now correctly uses the configured keystore private key password when establishing a connection to a Confluent Schema Registry with TLS (NOTE: Kafka extension users who currently use TLS to connect to a Confluent Schema Registry need to verify that their keystore private key password is correctly configured).

HiveMQ Swarm

  • Fixed an issue that caused a slight offset in the expiry of HiveMQ Swarm licenses.
  • Improved user feedback when timer commands are incorrectly configured in a HiveMQ Swarm scenario.
  • Improved log output when HiveMQ Swarm starts with an invalid configuration.


  • Fixed an issue that caused credential information contained in configuration properties to be ignored in broker test commands.
  • Adjusted file handling in the MQTT CLI to ensure platform independence.

Get HiveMQ 4.9.4 now

Have a great day, The HiveMQ Team

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