HiveMQ 4.9.1 Maintenance Release

The HiveMQ team is pleased to announce the availability of HiveMQ 4.9.1.

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

HiveMQ Server

• Reduced memory usage during the trace recording of MQTT packets.
• Fixed an issue that could prevent successful HiveMQ shutdown when the diagnostic mode is enabled.
• Improved the priority handling of HiveMQ extensions that use the same extension services to avoid possible conflicts.
• Fixed an issue where messages got enqueued and not delivered to connected clients after a node joined the cluster.
• Fixed an issue that could cause the HiveMQ broker to log duplicate extension starts during startup on some Windows desktop installations.
• Adjusted the naming of extension executors to facilitate accurate debugging.
• Fixed an issue in which overload protection could unnecessarily prevent a client from publishing.
• Fixed an issue where messages got enqueued and not delivered to connected clients after a node left the cluster.
• Improved clean-up handling when overload protection back-pressure ends for better memory usage.
• Added metric com.hivemq.shared-subscriptions.overall.current that tracks the current number of shared subscriptions on the HiveMQ broker.

HiveMQ Enterprise Bridge Extension

• Improved the clarity of HiveMQ Enterprise Bridge Extension loss of connection log entries.

HiveMQ Enterprise Distributed Tracing Extension

• Updated span attribute names in the HiveMQ Distributed Tracing Extension to support new OpenTelemetry semantic conventions.

HiveMQ Enterprise Extension for Google Cloud Pub/Sub

• Resolved an issue in the HiveMQ Enterprise Extension for Google Cloud Pub/Sub that could cause the extension to consume more memory than necessary.

MQTT CLI

• Adjusted the MQTT CLI tool to ensure correct handling of the no clean start option in PUBLISH and CONNECT operations.
• MQTT CLI now prints no malformed output on unsupported platforms for ANSI colorings.
• Added the -m:empty to the publish command of the MQTT CLI to specify an empty payload.
• The debian package of the MQTT CLI now supports headless java runtimes.
• Fixed an issue in the MQTT CLI tool to ensure that user properties are correctly included in UNSUBSCRIBE operations.
• Adjusted the MQTT CLI tool to ensure correct handling of the request problem information option in PUBLISH and CONNECT operations.

Have a great day, The HiveMQ Team