Subject: [VOTE] 4.3.1 RC0

Hello Kafka users, developers and client-developers, This is the first candidate for release of Apache Kafka 4.3.1. This is a bugfix release for the 4.3 line. The most significant fix is KAFKA-20616, a critical native memory leak in Kafka Streams caused by RocksDB ColumnFamily handles and ColumnFamilyOptions not being released (notably the offsets column family added for KIP-1035). The release also includes: - KAFKA-20663: Kafka Streams stale-offset / OffsetOutOfRangeException on restart (StateDirectory task-lock release on startup-manager close, and returning the committed offset from the newest segment first) - KAFKA-20673: AdminClient partition-leader APIs hang when a cached leader has left the cluster - KAFKA-20634 / KAFKA-20635: spurious group-coordinator errors after a partition leadership change - KAFKA-20535: improved async consumer CPU usage under low max.poll.records - Additional documentation updates (KIP-1035, KIP-1271 headers-aware state stores, 4.2/4.3 upgrade notes) Release notes for the 4.3.1 release: https://dist.apache.org/repos/dist/dev/kafka/4.3.1-rc0/RELEASE_NOTES.html *** Please download, test and vote by Monday, June 16, 2026, 5pm PT Kafka's KEYS file containing PGP keys we use to sign the release: https://downloads.apache.org/kafka/KEYS * Release artifacts to be voted upon (source and binary): https://dist.apache.org/repos/dist/dev/kafka/4.3.1-rc0/ * Docker release artifacts to be voted upon: apache/kafka:4.3.1-rc0 apache/kafka-native:4.3.1-rc0 * Maven artifacts to be voted upon: https://repository.apache.org/content/groups/staging/org/apache/kafka/ * Javadoc: https://dist.apache.org/repos/dist/dev/kafka/4.3.1-rc0/javadoc/index.html * Tag to be voted upon (off 4.3 branch) is the 4.3.1 tag: https://github.com/apache/kafka/releases/tag/4.3.1-rc0 * Documentation: https://kafka.apache.org/43/documentation.html * Protocol: https://kafka.apache.org/43/design/protocol * Successful CI builds for the 4.3 branch: Unit/integration tests: https://github.com/apache/kafka/actions/runs/27385247048 System tests: currently running; I will post the results in a follow-up reply to this thread. * Successful Docker Image Github Actions Pipeline for 4.3 branch: Docker Build Test Pipeline (JVM): https://github.com/apache/kafka/actions/runs/27377465712 Docker Build Test Pipeline (Native): https://github.com/apache/kafka/actions/runs/27380430965 Thanks, Bill Bejeck