Changelog

Aiven for Apache Kafka® 4.0

Apache Kafka® 4.0 is now available for Aiven for Apache Kafka services. You can create new services using Kafka 4.0 or upgrade existing services running Kafka 3.9 in KRaft mode.

Key changes

  • New consumer group protocol
    • Kafka 4.0 introduces an improved consumer group coordination protocol.
    • Older clients that do not support this protocol cannot connect to Kafka 4.0 clusters.
    • Upgrade client libraries before connecting.
  • Deprecated APIs and protocols removed
    • Kafka 4.0 removes API versions and protocol features that were previously deprecated.
    • Ensure all clients and tooling are compatible before upgrading.
    • This includes Kafka Connect, MirrorMaker 2, and custom client applications.
    • For details, see the Kafka 4.0 release notes.
  • `message.format.version` setting removed
    • Kafka 4.0 no longer uses the `message.format.version` topic-level setting.
    • Any configured value is ignored and removed during topic creation or update.
  • Timestamp difference setting replaced
    • Kafka 4.0 removes the `log.message.timestamp.difference.max.ms` service-level setting.
    • Use `log.message.timestamp.before_max_ms` and `log.message.timestamp.after_max_ms` instead.
    • For details, see KIP-937.
  • KRaft-only clusters
    • Kafka 4.0 requires all clusters to run in KRaft mode. ZooKeeper is no longer supported for metadata management.
    • If your service still uses ZooKeeper, upgrade to Kafka 3.9 and migrate to KRaft before moving to Kafka 4.0.
    • For details, see KRaft mode in Aiven for Apache Kafka.