HiveMQ 4.34.x to 4.35.x Migration Guide

This is a minor HiveMQ upgrade. HiveMQ 4.35 is a drop in replacement for HiveMQ 4.34.x.

You can learn more about all the new features HiveMQ 4.35 introduces in our release blogpost.

HiveMQ is prepackaged with all HiveMQ Enterprise Extensions (disabled), HiveMQ Data Hub, the open-source MQTT CLI tool, and the HiveMQ Swarm load-testing tool (MQTT CLI and HiveMQ Swarm are located in the tools folder of your HiveMQ installation).

HiveMQ 4.28 is the current HiveMQ LTS release. If you have not already done so, we recommend upgrading to HiveMQ version 4.28 or above.
To upgrade from the previous 4.9 LTS to HiveMQ 4.29 and above, you must first upgrade to the new 4.28 LTS version.
For more information, see the HiveMQ 4.9 to 4.28 Migration Guide, HiveMQ Rolling Upgrade Policy, and our Introducing Flexible MQTT Platform Upgrades with HiveMQ blog post.
When you migrate from one HiveMQ version to another, we recommend that you review the upgrade information for each version between your current HiveMQ version and the target HiveMQ version.
Note changes that are relevant to your use case and adjust your configuration as needed.
Java 21 will soon be required to run the HiveMQ Platform
Since the HiveMQ 4.28 release in April 2024, Java 21 is recommended to run the HiveMQ Platform.
For all HiveMQ versions released after April 2025, Java 21 will be required.
If you use the official HiveMQ container images, no action is required because these images have shipped with Java 21 since HiveMQ 4.28.
If you do not run HiveMQ as a container, or you build your own container image, we recommend updating to Java 21 before the April 2025 deadline.

Upgrade a HiveMQ Cluster

Rolling upgrades are supported, and it is possible to run HiveMQ version 4.34 and version 4.35 simultaneously in the same cluster. By default, the HiveMQ cluster enables all new cluster features when all nodes are upgraded to the new version. No manual intervention is required.

Please follow the instructions in our user guide to ensure a seamless and successful rolling upgrade.

Upgrade a Single-node HiveMQ Instance

  • Create a backup of the entire HiveMQ 4.34.x installation folder from which you want to migrate.

  • Install HiveMQ 4.35 as described in the HiveMQ Installation Guide.

  • Migrate the content of the config.xml and license files from your old HiveMQ 4.34.x installation.

  • To migrate your persistent data, copy everything from the data folder of your backup to the data folder of the new HiveMQ 4.35 installation.

HiveMQ Configuration File Changes

HiveMQ prevents the startup if your configuration file contains invalid values. For more information, see Configuration Validation.

HiveMQ Persistent Data Migration

When you migrate, HiveMQ 4.34 automatically updates the file storage formats of all the data that you copied into your new data folder.

To migrate the persistent data, you must copy everything in the data folder of the previous HiveMQ 4.34.x installation to the data folder of your new HiveMQ 4.35 installation.

Linux example
cp -r /opt/hivemq-4.34.0/data/* /opt/hivemq-4.35.0/data/

The first time you start HiveMQ 4.35, the file storage formats of the persistent data from your previous installation are automatically updated in the new persistent storage.

Outdated Metrics Removal

HiveMQ 4.35 introduces improved client overload protection.

Starting with HiveMQ 4.35, the following obsolete client overload protection metrics are no longer reported:

  • com.hivemq.overload-protection.credits.per-tick

  • com.hivemq.overload-protection.clients.average-credits

  • com.hivemq.overload-protection.credits.subtracted.publishes

  • com.hivemq.overload-protection.credits.subtracted.subscribes

  • com.hivemq.overload-protection.credits.subtracted.unsubscribes