Confluent Platform 7.3 Release Notes

7.3 is a major release of Confluent Platform that provides you with Apache Kafka® 3.3, the latest stable version of Kafka.

The technical details of this release are summarized below.

For more information about the 7.3 release, check out the release blog.

Kafka Brokers

Confluent Server

When configuring a replica placement on a topic, you can now assign replicas and observers to the same rack within the same topic replica placement constraint. This means you can use the replica placement constraint JSON to specify the same rack name in both the replicas and observers section. For example:

{
    "version": 2,
    "replicas": [
        {
            "count": 2,
            "constraints": {
                "rack": "east"
            }
        },
        {
            "count": 2,
            "constraints": {
                "rack": "west"
            }
        }
    ],
    "observers": [
      {
          "count": 1,
          "constraints": {
              "rack": "east"
          }
      },
      {
          "count": 1,
          "constraints": {
              "rack": "west"
          }
      }
    ],
    "observerPromotionPolicy":"under-min-isr"
}

Confluent Community / Apache Kafka

Confluent Platform 7.3 features Apache Kafka® 3.3. For a full list of the KIPs, features, and bug fixes, take a look at the latest Apache Kafka release notes, blog, or watch this overview of Kafka 3.3.

  • Apache Kafka® 3.3 has marked KRaft, the new metadata consensus mechanism for Kafka, production ready for new clusters. There are some features that are currently supported by Apache ZooKeeper™ mode that are not yet supported by KRaft mode. For details, see KIP-833.
  • In Confluent Platform 7.3, KRaft mode remains early-access due the ZooKeeper feature gaps listed in KIP-833.

Known issues

There is a known performance issue with version 0.17.2 of the JMX reporter, which was enabled with Confluent Platform version 7.2.5 to address security vulnerabilities: CVE-2022-38750, CVE-2022-38751, and CVE-2022-25857. As a workaround, you can manually install an earlier version of the JMX reporter, but note that earlier versions may contain the security vulnerabilities.

Cluster Management

Confluent for Kubernetes (formerly Confluent Operator)

For the list of Confluent for Kubernetes release versions compatible with this release of Confluent Platform, see the Supported Versions and Interoperability.

You can find the release notes for the latest release of Confluent for Kubernetes here.

Ansible Playbooks for Confluent Platform

New features

  • Ansible Playbooks for Confluent Platform are Red Hat certified now and are available on Red Hat Automation Hub, starting with CP-Ansible 7.0.X.
  • Ansible Playbooks for Confluent Platform provides a log collection playbook that will remotely collect logs from all Confluent Platform components across nodes.
  • Ansible Playbooks for Confluent Platform allows for configuring log redaction, where sensitive information is removed from log files.

Notable enhancements

Using Ansible Playbooks for Confluent Platform to upgrade from non-RBAC to RBAC is guarded with zero downtime and is officially supported.

Upgrade considerations

Ansible Playbooks for Confluent Platform 7.3 does not support Ansible 2.9 or Python 2.x because those runtimes are end-of-life. Upgrade to Ansible 2.11+ or Python 3.6+ to use Ansible Playbooks for Confluent Platform 7.3.

For more information, see the Ansible Playbooks for Confluent Platform documentation.

Kafka Streams

Pause/resume - You can now dynamically pause and resume Kafka Streams applications. Supporting methods for these operations are defined within the KafkaStreams class.

ksqlDB

  • Confluent Platform 7.3 packages ksqlDB version 0.28.2.
  • Persistent query pause/resume - ksqlDB 0.28.2 leverages the new Kafka Streams pause and resume functionality which can dynamically pause and resume persistent queries using the PAUSE and RESUME commands.
  • PROTOBUF_NOSR serialization format - The PROTOBUF_NOSR serialization format has been introduced to support Protocol Buffers without using Schema Registry.
  • ASSERT support for testing - ASSERT SCHEMA and ASSERT TOPIC have been introduced to provide enriched testing support.
  • Wildcard Struct references - You can now specify a wildcard (*) when referencing Structs, which will expand the reference to include all Struct fields.
  • Aggregations without grouping - YOu can now perform aggregations without using a grouping column.

Connect

Connect on z/OS - Confluent’s certified version of Connect for IBM’s z/OS operating system allows you to run certified premium connectors on the z/OS operating system. For more information about the premium connectors certified on z/OS, see the Certified Connectors on z/OS. section.

Other improvements and changes

Starting October 1st, 2025, a new Enterprise license key for Customer-managed Confluent Platform for Confluent Cloud subscription is being introduced. This new license key entitles you to use self-managed Confluent Platform components exclusively with Confluent Cloud services.

Prerequisites for installing the license key

  1. Ensure all your self-managed components are connected with Confluent Cloud and used for Confluent Cloud broker-related use cases. Confluent does not provide support for any self-managed Confluent Platform components that are used exclusively for Confluent Platform broker use cases under the Customer-managed Confluent Platform for Confluent Cloud subscription.
  2. You must upgrade Confluent Platform to the recommended minimum patch version for each minor version of Confluent Platform.

Warning

Applying this new Enterprise license key to Confluent Platform components or Control Center before upgrading them causes the license key update to fail. The failure is recorded as an error in the component logs, and it is shown on the Control Center if the license key was applied using Control Center.

If you are an existing customer, your existing license key will continue to function until its expiration date.

Note the following for Customer-managed Confluent Platform for Confluent Cloud:

  • This license key is solely for the use of self-managed Confluent Platform components with Confluent Cloud. Confluent does not provide support for any self-managed Confluent Platform components that are used exclusively for Confluent Platform broker use cases under the ‘Customer-managed Confluent Platform for Confluent Cloud subscription.
  • If you are using Control Center, apply the license key in Control Center (recommended). For more information, see Manage Confluent Platform Licenses using Control Center. Alternatively, you can configure the confluent.license parameter in the Connect worker configuration, or at the individual connector level for enterprise support. Enterprise support is not provided for Schema Registry and REST Proxy unless the confluent-security package is installed on all nodes and a valid Enterprise license key is configured. For more information, see Configure Component Licenses for more details.

Note

Confluent Platform Connect workers now perform a pre-check during startup to validate critical Confluent licensing libraries. This prevents potential runtime errors by ensuring all required libraries are present and compatible. If this check fails due to missing or incompatible libraries, the worker will not start. To avoid related library conflicts, use the plugin.path configuration property to load connectors and their dependencies. Avoid using the CLASSPATH environment variable for plugins, as this can lead to unpredictable failures in the Connect framework as described in the Install a plugin.

How to Download

Confluent Platform is available for download at https://www.confluent.io/download/. See the Install Confluent Platform On-Premises section for detailed information.

Important

The Confluent Platform package includes Confluent Server by default and requires a confluent.license key in your server.properties file. Starting with Confluent Platform 5.4.x, the Confluent Server broker checks for a license during start-up. You must supply a license string in each broker’s properties file using the confluent.license property as below:

confluent.license=LICENCE_STRING_HERE_NO_QUOTES

If you want to use the Kafka broker, download the confluent-community package. The Kafka broker is the default in all Debian or RHEL and CentOS packages.

For more information about migrating to Confluent Server, see Migrate Confluent Platform to Confluent Server.

To upgrade Confluent Platform to a newer version, check the Upgrade Confluent Platform documentation.

Supported Versions and Interoperability

For the supported versions and interoperability of Confluent Platform and its components, see Supported Versions and Interoperability for Confluent Platform.

Questions?

If you have questions regarding this release, feel free to reach out via the community mailing list or community Slack. Confluent customers are encouraged to contact our support directly.