This 93rd edition of the Kafka Monthly Digest covers what happened in the Apache Kafka community in October 2025.
Releases
There is 1 new release and 2 releases are in progress:
4.0.1
The vote on 4.0.1 RC2 passed on October 8 and Christo Lolov released 4.0.1 on October 13. This bugfix release fixes 49 Jiras including over 10 blocker issues. You can find more details in the announcement, the release notes and in the release plan in the wiki.
4.1.1
On October 6, Lianet Magrans volunteered to run the 4.1.1 release. She published RC0 on October 22, but a minor logging issue was found. She then published RC1 on October 23 but again a small issue was found. She published RC2 on October 27 and the vote is currently on-going. You can find the release plan in the wiki.
4.2.0
The release process for Kafka 4.2.0 continued. KIP Freeze happened on October 29, the next milestone is Feature Freeze on November 19. You can find the release plan in the wiki.
Kafka Improvement Proposals
- KIP-1222: Acquisition lock timeout renewal in share consumer explicit mode: When using queues, consumers must process, and accept or reject records within the acquisition lock timeout. When failing to do so, records are released and potentially eligible for re-delivery if they have not exceed their delivery limits. If a record takes a long time to be processed, the consumer currently has no way to request an extension of the timeout and this can lead to records failing to be processed. This KIP introduces a new acknowledgement type for consumers to renew their acquisition lock if they need more time to process a record.
- KIP-1223: Add user tag to DeprecatedRequestsMetric: KIP-896 added metrics to identify if deprecated APIs are used by clients. The metric contains the API name, the version used as well as the client software name and version. In some cases this is not enough to identify who owns that application. This KIP proposes adding the principal name as a label to the existing metric to help identify users using deprecated APIs. As this risks creating many metric series, the new label would only be added if a new configuration,
kafka.metrics.deprecated.requests.tag.user.enabled, is set to true.
- KIP-1233: Maximum lengths for resource names and IDs: Kafka uses names and identifiers for all the resources it exposes such as topic names, consumer group names, rack ids, etc. Some of these have restrictions on their size, for example topics are limited to 249 characters, but for many there isn't a clear or documented limit. This KIP aims at defining limits for all names and identifiers to improve error handling when limits are reached and prevent accidental and malicious abuses.
Community Releases
I selected releases of some open source community projects:
- Kroxylicious 0.17.0: Kroxylicious is an open source pluggable framework for writing network proxies that understand the Apache Kafka protocol. The project now has a Maven archetype for easily setting up a project for creating a custom filter. It introduces a new SASL authentication filter that supports PLAIN, SCRAM-SHA 256 and 512, and OAUTHBEARER. It also adds support for Azure KMS for record encryption.
- Debezium 3.3: Debezium is a Change Data Capture platform. This new releases brings many new features and improvements to all the connectors and components. In particular all the core connectors (MariaDB, MongoDB, MySQL, Oracle, PostgreSQL, SQL Server) now support exactly-once semantics.
Blogs
I selected some interesting blog articles that were published last month:
To learn more about Kafka, visit Red Hat Developer's Apache Kafka topic page.
