Upgrading to Kafka 4

Kafka 4 has been released. In order to successfully upgrade there are a few things to take into account. Kafka 4 has removed some topic configurations, one of which can be set through Axual governance. It needs to be removed from Kafka. Axual provides an application that can be configured to remove this topic configuration from every Kafka topic, called kafka config cleanup.

There is a list of old Kafka clients and old Kafka API versions that have been removed from Kafka 4. Before upgrading, it is a good idea to identify any such clients connected to the Kafka cluster, so that these do not run into any issues after the upgrade. The process of identifying such clients is documented here.

Once the topic configs are taken care of and older clients have been identified, the actual upgrade to Kafka 4 is straightforward as explained in upgrade to Kafka 4.