clolov commented on code in PR #786: URL: https://github.com/apache/kafka-site/pull/786#discussion_r2695111200
########## content/en/blog/releases/ak-4.2.0.md: ########## @@ -0,0 +1,168 @@ +--- +date: 2026-01-14 +title: Apache Kafka 4.2.0 Release Announcement +linkTitle: AK 4.2.0 +author: Christo Lolov +--- + +<!-- + Licensed to the Apache Software Foundation (ASF) under one or more + contributor license agreements. See the NOTICE file distributed with + this work for additional information regarding copyright ownership. + The ASF licenses this file to You under the Apache License, Version 2.0 + (the "License"); you may not use this file except in compliance with + the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +--> + + + + +We are proud to announce the release of Apache Kafka® 4.2. This release contains many new features and improvements. This blog post will highlight some of the more prominent ones. For a full list of changes, be sure to check the [release notes](https://downloads.apache.org/kafka/4.2.0/RELEASE_NOTES.html). + +Kafka Queues (Share Groups) is now production-ready with new features like the RENEW acknowledgement type for extended processing times, adaptive batching for coordinators, and comprehensive lag metrics. + +Kafka Streams gains dead letter queue support in exception handlers, anchored wall-clock punctuation for deterministic scheduling, and the new server-side rebalance protocol reaches GA with a limited feature set. + +This release also delivers significant improvements to consistency and observability: CLI tools now feature standardized arguments like --bootstrap-server across all tools, metric naming has been corrected to follow the kafka.COMPONENT convention, and new idle ratio metrics provide better visibility into controller and MetadataLoader performance. + +Security is enhanced with a new allowlist connector client configuration override policy, while thread-safety improvements to RecordHeader eliminate concurrency risks. + +Additional highlights include external schema support in JsonConverter for reduced message sizes, dynamic configuration for remote log manager thread pools, and rack ID exposure in the Admin API for consumer and share group members. + +See the [Upgrading to 4.2](https://kafka.apache.org/documentation.html#upgrade_4_2_0) section in the documentation for the list of notable changes and detailed upgrade steps. + +## Deprecation Notices +* [KIP-1136: Make ConsumerGroupMetadata an interface](https://cwiki.apache.org/confluence/x/r45EF) + Deprecates the constructors of ConsumerGroupMetadata. Marked for removal in Apache Kafka 5.0. + +* [KIP-1193: Deprecate MX4j support](https://cwiki.apache.org/confluence/x/dAxJFg) + Adds various deprecation warnings for MX4j. Marked for removal in Apache Kafka 5.0. + +* [KIP-1195: deprecate and remove org.apache.kafka.streams.errors.BrokerNotFoundException](https://cwiki.apache.org/confluence/x/8AxJFg) Review Comment: I kinda made a judgement call on this one. I believe historically we have listed all KIPs split across Kafka Brokers/Clients, Kafka Streams and Kafka Connect. These 3 in particular focus mainly on deprecate something in 4.2 and remove in 5.0, hence I moved them to a separate category. I am okay with removing the Deprecation Notices section and moving these KIPs into one of the respective 3 categories, I just felt they would get a bit lost. Would you prefer this approach @mjsax? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
