Hi Christo, It looks like you did not close the RC1 Maven artifacts in Nexus. All the 4.2.0 artifacts are from Jan 13 so presumably it's still RC0.
For example, see https://repository.apache.org/content/groups/staging/org/apache/kafka/kafka_2.13/4.2.0/ Thanks, Mickael On Mon, Jan 19, 2026 at 5:28 PM Christo Lolov <[email protected]> wrote: > > Hello Kafka users, developers and client-developers, > > This is the RC1 candidate for release of Apache Kafka 4.2.0. > > This release has many exciting changes: > * 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 brings the server-side rebalance protocol to GA with a > limited feature set, adds dead letter queue support in exception > handlers, introduces anchored wall-clock punctuation for deterministic > scheduling, and gives users full control over whether to send a leave > group request on closing. > * 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. > > Release notes for the 4.2.0 release: > https://dist.apache.org/repos/dist/dev/kafka/4.2.0-rc1/RELEASE_NOTES.html > > *** Please download, test and vote by Monday, January 26, 10am UTC > > Kafka's KEYS file containing PGP keys we use to sign the release: > https://kafka.apache.org/KEYS > > * Release artifacts to be voted upon (source and binary): > https://dist.apache.org/repos/dist/dev/kafka/4.2.0-rc1/ > > * Docker release artifacts to be voted upon: > apache/kafka:4.2.0-rc1 > apache/kafka-native:4.2.0-rc1 > > * 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/4.2.0-rc1/javadoc/index.html > > * Tag to be voted upon (off 4.2 branch) is the 4.2.0 tag: > https://github.com/apache/kafka/releases/tag/4.2.0-rc1 > > * Documentation: > https://kafka.apache.org/42/documentation.html > > * Protocol: > https://kafka.apache.org/42/protocol.html > > * Successful CI builds for the 4.2 branch: > Unit/integration tests: The build for the 4.2.0-rc1 tag can be found > at https://github.com/apache/kafka/actions/runs/21135565337/job/60779418474 > There is a single failing test which I have since retried. > > System tests: I have setup my E2E environment and will share test > results in the next ~24 hours. > Chia-Ping has been very generous and helpful and is also running a > parallel environment at > https://jenkins.opensource4you.tw/job/kafka-e2e/636/ > > * Successful Docker Image Github Actions Pipeline for 4.2 branch: > Docker Build Test Pipeline (JVM): > https://github.com/apache/kafka/actions/runs/21135593072 > Docker Build Test Pipeline (Native): > https://github.com/apache/kafka/actions/runs/21136272782 > > Thanks, > Christo > > -- > You received this message because you are subscribed to the Google Groups > "kafka-clients" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/d/msgid/kafka-clients/CANF%2Ba5c5USZr9TG1YrXcg9zuy2tnZdgC4MyW6QYtJ30eR_5VvQ%40mail.gmail.com.
