4.19.x to 4.20.x Migration Guide

This is a minor HiveMQ upgrade. HiveMQ 4.20 is a drop in replacement for HiveMQ 4.19.x.

You can learn more about all the new features HiveMQ 4.20 introduces in our release blogpost.

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

Starting with the HiveMQ 4.9 LTS release, HiveMQ provides enhanced version compatibility for all HiveMQ releases.
For more information, see HiveMQ Rolling Upgrade Policy and our Introducing Flexible MQTT Platform Upgrades with HiveMQ blog post.

When you migrate from one HiveMQ version to another, 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.

Upgrade a HiveMQ Cluster

Rolling upgrades are supported, and it is possible to run HiveMQ version 4.19 and version 4.20 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.

For more information, see HiveMQ Clusters.

Upgrade a Single-node HiveMQ Instance

  • Create a backup of the entire HiveMQ 4.19.x installation folder from which you want to migrate

  • Install HiveMQ 4.20 as described in the HiveMQ Installation Guide

  • Migrate the contents of the configuration file from your old HiveMQ 4.19.x installation

  • To migrate your persistent data, copy everything from the data folder of your backup to the data folder of the new HiveMQ 4.20 installation.

Configuration File Changes

HiveMQ 4.20 makes some changes to configuration files.
Starting with HiveMQ 4.20, the HiveMQ Data Hub is enabled by default and is configured with a different XML-tag name.

If you have used Data Hub (previously called Data Governance Hub) prior to HiveMQ 4.20, check the Data Hub Config Change section for additional information.

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

Persistent Data Migration

When you migrate, HiveMQ 4.20 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 4.19.x installation to the data folder of your new HiveMQ 4.20 installation.

Linux example
cp -r /opt/hivemq-4.19.0/data/* /opt/hivemq-4.20.0/data/

The first time you start HiveMQ 4.20, the file storage formats of the persistent data from your previous installation are automatically updated in the new persistent storage.

Configuration and Default Behavior Change for HiveMQ Data Hub

In HiveMQ 4.20, HiveMQ Data Governance Hub is renamed to HiveMQ Data Hub. The XML tags in the HiveMQ config.xml file reflect the new name and have a new default behavior. Starting with HiveMQ 4.20, the HiveMQ Data Hub data-validation and behavior-validation features are enabled by default.

To disable the Data Hub, you must set the enabled tags for data validation and behavior validation in the data-hub section of your HiveMQ config.xml file to false.

Example configuration to disable the Data Hub in your HiveMQ config.xml file

New Control Center Permissions

In HiveMQ 4.20, the HiveMQ Control Center adds the option configure granular permission of managing schemas, and policies of Data Hub.

If you currently use the HiveMQ Enterprise Security Extension to restrict access to your control center and you want specific users to continue to have access to such information, you must grant the new permissions to these users.

You can assign one or more of the new permissions to the appropriate users or roles as desired.

Table 1. New control center permissions
Permission Description Additional permissions


allowed to view schema list


allowed to view schema detail


allowed to create/edit schemas


allowed to view data policy list



allowed to view behavior policy list



allowed to view data policy detail



allowed to view behavior policy detail



allowed to view data hub charts



allowed to create/edit data policies



allowed to create/edit behavior policies


Some new permissions rely on the presence of other permissions. Permissions required to gain full usability, are listed in the Additional permissions column. For example, when you grant the permission HIVEMQ_EDIT_DATA_BEHAVIOR_POLICY, you need to grant HIVEMQ_VIEW_DATA_CLIENT_ID, and HIVEMQ_VIEW_DATA_TOPIC to ensure the proper usability.

For more information, see Control Center Access Control Permissions

Changes in the OpenAPI Integration for the Data Hub

HiveMQ 4.20 introduces changes to the REST API tags for the Data Hub.
The changes in the tags of the REST resources for Data Hub result in different names in the generated classes.

If you currently use the OpenAPI integration for the Data Hub to generate code, you must adjust your code to accommodate the changes. The most significant change is to replace /data-governance-hub/ by /data-hub/.

For more information, see HiveMQ REST API.

Renamed Policy Functions with Namespace in the HiveMQ Data Hub

HiveMQ 4.20 renames one existing policy function with the namespace as a prefix:

  • UserProperties.add changes to Mqtt.UserProperties.add

The new naming helps organize functions by their purpose for easier policy management. As new functions are added, each function will be prefixed with the appropriate namespace.

Data Policy Default Behavior for Failed Validations

HiveMQ 4.20 comes with an updated default behavior in the Data Hub data policy engine.

In previous versions, the policy engine automatically dropped the message when a validation failed. Now, we have changed the drop behavior to make the handling of dropped messages more explicit and easier to understand.

In HiveMQ 4.20, we introduce a new `Mqtt.drop`function that can drop any MQTT message. You can even drop valid messages for debugging purposes. For more information, see Functions.

To achieve the same behavior as before HiveMQ 4.20, onFailure actions need an extra Mqtt.drop at the end of the action pipeline, if no other terminal function is provided.

Policy Migration

If you have existing policies that contain outdated UserProperties.add functions or require an additional Mqtt.drop, use the following procedure to migrate the affected policies to the new Mqtt.UserProperties.add function names:

  1. To get all existing policies in the broker enter:
    curl -X GET http://localhost:8888/api/v1/data-validation/policies.

  2. Change all functionId fields in affected policies to use the new function names (Mqtt.MqttUserProperties.add) and add to the onFailure action’s pipeline an additional Mqtt.drop

  3. Delete each of the outdated policies one by one with the following command:
    curl -X DELETE -H "Content-Type: application/json" http://localhost:8888/api/v1/data-validation/policies/{policyId}.

  4. Re-upload your newly revised policies one by one with the following command:
    curl -X POST --data @policy.json -H "Content-Type: application/json" http://localhost:8888/api/v1/data-validation/policies.

Changed Metric Names for Data Hub

HiveMQ 4.20 renamed the metrics according to the product name: data-governance-hub to data-hub. For more information, see Data hub Metrics

MQTT CLI command update

With new capabilities of Data Hub for behavior policies we changed command names in our MQTT CLI.

  • mqtt hivemq policies is changed to mqtt hivemq data-policy

  • mqtt hivemq schemas is changed to mqtt hivemq schema