This 96th edition of the Kafka Monthly Digest covers what happened in the Apache Kafka community in January 2026.
This also marks the 8th anniversary of this blog series!
Releases
There are 4 releases in progress:
4.2.0
The release process for Kafka 4.2.0 continued. Christo Lolov published the RC0 on January 13, however the community found a regression in the Connect REST API (KAFKA-20076). RC1 was published on January 19 but a regression in the Docker image was found (KAFKA-20093). Subsequently RC2 was published on January 27 but this time an issue with KIP-1034 was found, so we will need another RC. You can find the release plan in the wiki.
3.9.2
PoAn Yang published the first release candidate, 3.9.2 RC0, on January 15. The vote is currently ongoing. You can find the release plan in the wiki.
4.1.2
On January 27, Andrew Schofield volunteered to be the release manager for Apache Kafka 4.1.2. The release is expected in February. You can find the release plan in the wiki.
4.0.2
On January 27, Viktor Somogyi-Vass volunteered to be the release manager for Apache Kafka 4.0.2. The release is expected in February. You can find the release plan in the wiki.
Kafka Improvement Proposals
- KIP-1262: Enable auto-formatting directories: At the moment, administrators need to format the storage of brokers before starting them up for the first time. To do so they must use the
kafka-storage.shtool and provide the cluster Id. This KIP aims at simplifying the process of setting up new brokers and observer controllers by skipping the formatting step.
- KIP-1272: Support compacted topic in tiered storage: Tiered storage can only be enabled on non-compacted topics. In order to expand this feature to compacted topics, the KIP proposes compaction semantics when topic data is spread across local and remote storage.
- KIP-1274: Deprecate and remove support for Classic rebalance protocol in KafkaConsumer: The new consumer rebalance protocol (KIP-848) was marked production ready in Kafka 4.0. However,
KafkaConsumerstill defaults to the old, now called classic, protocol. This KIP proposes a timeline to switch the default protocol as well as deprecate and remove the classic protocol.
- KIP-1275: New command line tool for unclean recovery: When running an unclean election, a random out of sync replica is picked as the new leader. In some cases this can lead to major data loss, for example if a new replica was recently added and did not have any data yet. This KIP introduces new APIs as well as a new tool,
kafka-unclean-recovery.sh, to help recover offline partitions and minimize potential data loss.
Community Releases
I selected some new open source community project releases:
- strimzi-kafka-operator 0.50: Strimzi is a Kubernetes Operator for running Kafka. It now uses Java 21 as the runtime and language level. The
apimodule still supports Java 11, but will be updated to 21 as well in Strimzi 1.0. It also adds support for configuringhostUsersin pods.
- librdkafka 2.13: Librdkafka is a Kafka client in C/C++. This new release updates the supported version for the CreateAcls, DescribeAcls, DeleteAcls, DescribeGroups, DeleteTopics, DeleteRecords, CreatePartitions and DeleteGroups APIs. It also includes a few correctness and stability fixes.
Blogs
I selected some interesting blog articles that were published last month:
