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Posted to users@kafka.apache.org by PoAn Yang <ya...@gmail.com> on 2026/05/12 12:14:21 UTC
[VOTE] 4.2.1 RC4
Hello Kafka users, developers and client-developers,
This is the second candidate for release of Apache Kafka 4.2.1.
This is the first bug fix release for Apache Kafka 4.2 with fixes as
described in the release notes. In the second candidate, it adds
KAFKA-19851 and KAFKA-20380.
Release notes for the 4.2.1 release:
https://dist.apache.org/repos/dist/dev/kafka/4.2.1-rc4/RELEASE_NOTES.html
Please download, test and vote by Tuesday, May 19, 9pm PT.
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/4.2.1-rc4/
* Docker release artifacts to be voted upon:
apache/kafka:4.2.1-rc4
apache/kafka-native:4.2.1-rc4
* 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/4.2.1-rc4/javadoc/index.html
* Tag to be voted upon (off 4.2 branch) is the 4.2.1 tag:
https://github.com/apache/kafka/releases/tag/4.2.1-rc4
* Documentation:
https://kafka.apache.org/42/documentation.html
* Protocol:
https://kafka.apache.org/42/design/protocol/
* Successful CI builds for the 4.2 branch:
Unit/integration tests:
https://github.com/apache/kafka/actions/runs/25717277218
System tests: https://jenkins.opensource4you.tw/job/kafka-e2e/746/,
https://jenkins.opensource4you.tw/job/kafka-e2e/747/,
https://jenkins.opensource4you.tw/job/kafka-e2e/748/
* Successful Docker Image Github Actions Pipeline for 4.2 branch:
Docker Build Test Pipeline (JVM):
https://github.com/apache/kafka/actions/runs/25728469988
Docker Build Test Pipeline (Native):
https://github.com/apache/kafka/actions/runs/25728486740
Thanks,
PoAn
Re: [kafka-clients] [VOTE] 4.2.1 RC4
Posted by Josep Prat via dev <de...@kafka.apache.org>.
Hi,
I did the following:
- checked the signatures and checksums
- built from source
- ran the tests
- Tested Docker Images:
-- can start
-- can create topics
- ran quickstart
- ran sample apps with consumer groups
- checked Java client interaction from artifacts (admin, producer, consumer
and streams)
- checked Tiered Storage offloads to remote storage (with Aiven's plugin)
- checked Kafka Connect
Verified on Linux with JDK 21
+1 (binding)
On Tue, May 12, 2026 at 5:31 PM Lucas Brutschy via dev <de...@kafka.apache.org>
wrote:
> +1 (non-binding)
>
> Verified on macOS arm64, JDK 17:
>
> * GPG signatures and SHA512 checksums for source, binary, and
> site-docs tarballs
> * LICENSE/NOTICE present
> * Built source with ./gradlew jar — BUILD SUCCESSFUL
> * git tag 4.2.1-rc4 commit matches the shipped jar's
> kafka-version.properties commitId
> * KRaft quickstart: format --standalone, broker start,
> topic/produce/consume
> * KIP-1071 streams group: ran WordCountDemo with
> group.protocol=streams; logs show StreamsGroupHeartbeatRequestManager
> and counts aggregate correctly across rounds. Exercised
> kafka-streams-groups.sh --list/--describe/--members/--state/--offsets/
> --verbose; --reset-offsets correctly rejected while Stable, accepted
> once Empty
> * Docker images apache/kafka and apache/kafka-native: both start,
> produce/consume works against each, commitId matches the tag
> * Documentation, javadoc, protocol, release-notes, and GitHub tag URLs
> all reachable
> * Maven staging artifacts present with Last-Modified matching the rc4
> tag date
> * Did not rerun the full test suite locally; relied on the linked
> Apache CI run
>
> Thanks PoAn for running the release!
>
> On Tue, May 12, 2026 at 2:14 PM PoAn Yang <ya...@gmail.com> wrote:
> >
> > Hello Kafka users, developers and client-developers,
> >
> > This is the second candidate for release of Apache Kafka 4.2.1.
> >
> > This is the first bug fix release for Apache Kafka 4.2 with fixes as
> described in the release notes. In the second candidate, it adds
> KAFKA-19851 and KAFKA-20380.
> >
> > Release notes for the 4.2.1 release:
> >
> https://dist.apache.org/repos/dist/dev/kafka/4.2.1-rc4/RELEASE_NOTES.html
> >
> > Please download, test and vote by Tuesday, May 19, 9pm PT.
> >
> > 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/4.2.1-rc4/
> >
> > * Docker release artifacts to be voted upon:
> > apache/kafka:4.2.1-rc4
> > apache/kafka-native:4.2.1-rc4
> >
> > * 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/4.2.1-rc4/javadoc/index.html
> >
> > * Tag to be voted upon (off 4.2 branch) is the 4.2.1 tag:
> > https://github.com/apache/kafka/releases/tag/4.2.1-rc4
> >
> > * Documentation:
> > https://kafka.apache.org/42/documentation.html
> >
> > * Protocol:
> > https://kafka.apache.org/42/design/protocol/
> >
> > * Successful CI builds for the 4.2 branch:
> > Unit/integration tests:
> https://github.com/apache/kafka/actions/runs/25717277218
> > System tests: https://jenkins.opensource4you.tw/job/kafka-e2e/746/,
> https://jenkins.opensource4you.tw/job/kafka-e2e/747/,
> https://jenkins.opensource4you.tw/job/kafka-e2e/748/
> >
> > * Successful Docker Image Github Actions Pipeline for 4.2 branch:
> > Docker Build Test Pipeline (JVM):
> https://github.com/apache/kafka/actions/runs/25728469988
> > Docker Build Test Pipeline (Native):
> https://github.com/apache/kafka/actions/runs/25728486740
> >
> > Thanks,
> > PoAn
> >
> > --
> > 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 kafka-clients+unsubscribe@googlegroups.com.
> > To view this discussion visit
> https://groups.google.com/d/msgid/kafka-clients/CAL6fUMRTp3Y7%2BEsbZftMQJQvotbSXop-DohkxN4h_di%2B7tSAQQ%40mail.gmail.com
> .
>
--
[image: Aiven] <https://www.aiven.io>
*Josep Prat*
Sr Engineering Director, Streaming Services, *Aiven*
josep.prat@aiven.io | +491715557497
aiven.io <https://www.aiven.io/>
[image: LinkedIn]
<https://www.linkedin.com/company/aiven/posts/?feedView=all> [image: X]
<https://x.com/aiven_io> [image: GitHub] <https://github.com/aiven> [image:
YouTube] <ht...@Aiven_io> [image: Facebook]
<https://www.facebook.com/aivencloud>
*Aiven Deutschland GmbH*
Rosenthaler Straße 43-45, 10178 Berlin
Geschäftsführer: Oskari Saarenmaa, Kenneth Chen
Amtsgericht Charlottenburg, HRB 209739 B
Re: [kafka-clients] [VOTE] 4.2.1 RC4
Posted by Josep Prat via users <us...@kafka.apache.org>.
Hi,
I did the following:
- checked the signatures and checksums
- built from source
- ran the tests
- Tested Docker Images:
-- can start
-- can create topics
- ran quickstart
- ran sample apps with consumer groups
- checked Java client interaction from artifacts (admin, producer, consumer
and streams)
- checked Tiered Storage offloads to remote storage (with Aiven's plugin)
- checked Kafka Connect
Verified on Linux with JDK 21
+1 (binding)
On Tue, May 12, 2026 at 5:31 PM Lucas Brutschy via dev <de...@kafka.apache.org>
wrote:
> +1 (non-binding)
>
> Verified on macOS arm64, JDK 17:
>
> * GPG signatures and SHA512 checksums for source, binary, and
> site-docs tarballs
> * LICENSE/NOTICE present
> * Built source with ./gradlew jar — BUILD SUCCESSFUL
> * git tag 4.2.1-rc4 commit matches the shipped jar's
> kafka-version.properties commitId
> * KRaft quickstart: format --standalone, broker start,
> topic/produce/consume
> * KIP-1071 streams group: ran WordCountDemo with
> group.protocol=streams; logs show StreamsGroupHeartbeatRequestManager
> and counts aggregate correctly across rounds. Exercised
> kafka-streams-groups.sh --list/--describe/--members/--state/--offsets/
> --verbose; --reset-offsets correctly rejected while Stable, accepted
> once Empty
> * Docker images apache/kafka and apache/kafka-native: both start,
> produce/consume works against each, commitId matches the tag
> * Documentation, javadoc, protocol, release-notes, and GitHub tag URLs
> all reachable
> * Maven staging artifacts present with Last-Modified matching the rc4
> tag date
> * Did not rerun the full test suite locally; relied on the linked
> Apache CI run
>
> Thanks PoAn for running the release!
>
> On Tue, May 12, 2026 at 2:14 PM PoAn Yang <ya...@gmail.com> wrote:
> >
> > Hello Kafka users, developers and client-developers,
> >
> > This is the second candidate for release of Apache Kafka 4.2.1.
> >
> > This is the first bug fix release for Apache Kafka 4.2 with fixes as
> described in the release notes. In the second candidate, it adds
> KAFKA-19851 and KAFKA-20380.
> >
> > Release notes for the 4.2.1 release:
> >
> https://dist.apache.org/repos/dist/dev/kafka/4.2.1-rc4/RELEASE_NOTES.html
> >
> > Please download, test and vote by Tuesday, May 19, 9pm PT.
> >
> > 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/4.2.1-rc4/
> >
> > * Docker release artifacts to be voted upon:
> > apache/kafka:4.2.1-rc4
> > apache/kafka-native:4.2.1-rc4
> >
> > * 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/4.2.1-rc4/javadoc/index.html
> >
> > * Tag to be voted upon (off 4.2 branch) is the 4.2.1 tag:
> > https://github.com/apache/kafka/releases/tag/4.2.1-rc4
> >
> > * Documentation:
> > https://kafka.apache.org/42/documentation.html
> >
> > * Protocol:
> > https://kafka.apache.org/42/design/protocol/
> >
> > * Successful CI builds for the 4.2 branch:
> > Unit/integration tests:
> https://github.com/apache/kafka/actions/runs/25717277218
> > System tests: https://jenkins.opensource4you.tw/job/kafka-e2e/746/,
> https://jenkins.opensource4you.tw/job/kafka-e2e/747/,
> https://jenkins.opensource4you.tw/job/kafka-e2e/748/
> >
> > * Successful Docker Image Github Actions Pipeline for 4.2 branch:
> > Docker Build Test Pipeline (JVM):
> https://github.com/apache/kafka/actions/runs/25728469988
> > Docker Build Test Pipeline (Native):
> https://github.com/apache/kafka/actions/runs/25728486740
> >
> > Thanks,
> > PoAn
> >
> > --
> > 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 kafka-clients+unsubscribe@googlegroups.com.
> > To view this discussion visit
> https://groups.google.com/d/msgid/kafka-clients/CAL6fUMRTp3Y7%2BEsbZftMQJQvotbSXop-DohkxN4h_di%2B7tSAQQ%40mail.gmail.com
> .
>
--
[image: Aiven] <https://www.aiven.io>
*Josep Prat*
Sr Engineering Director, Streaming Services, *Aiven*
josep.prat@aiven.io | +491715557497
aiven.io <https://www.aiven.io/>
[image: LinkedIn]
<https://www.linkedin.com/company/aiven/posts/?feedView=all> [image: X]
<https://x.com/aiven_io> [image: GitHub] <https://github.com/aiven> [image:
YouTube] <ht...@Aiven_io> [image: Facebook]
<https://www.facebook.com/aivencloud>
*Aiven Deutschland GmbH*
Rosenthaler Straße 43-45, 10178 Berlin
Geschäftsführer: Oskari Saarenmaa, Kenneth Chen
Amtsgericht Charlottenburg, HRB 209739 B
Re: [kafka-clients] [VOTE] 4.2.1 RC4
Posted by Lucas Brutschy via dev <de...@kafka.apache.org>.
+1 (non-binding)
Verified on macOS arm64, JDK 17:
* GPG signatures and SHA512 checksums for source, binary, and
site-docs tarballs
* LICENSE/NOTICE present
* Built source with ./gradlew jar — BUILD SUCCESSFUL
* git tag 4.2.1-rc4 commit matches the shipped jar's
kafka-version.properties commitId
* KRaft quickstart: format --standalone, broker start,
topic/produce/consume
* KIP-1071 streams group: ran WordCountDemo with
group.protocol=streams; logs show StreamsGroupHeartbeatRequestManager
and counts aggregate correctly across rounds. Exercised
kafka-streams-groups.sh --list/--describe/--members/--state/--offsets/
--verbose; --reset-offsets correctly rejected while Stable, accepted
once Empty
* Docker images apache/kafka and apache/kafka-native: both start,
produce/consume works against each, commitId matches the tag
* Documentation, javadoc, protocol, release-notes, and GitHub tag URLs
all reachable
* Maven staging artifacts present with Last-Modified matching the rc4
tag date
* Did not rerun the full test suite locally; relied on the linked
Apache CI run
Thanks PoAn for running the release!
On Tue, May 12, 2026 at 2:14 PM PoAn Yang <ya...@gmail.com> wrote:
>
> Hello Kafka users, developers and client-developers,
>
> This is the second candidate for release of Apache Kafka 4.2.1.
>
> This is the first bug fix release for Apache Kafka 4.2 with fixes as described in the release notes. In the second candidate, it adds KAFKA-19851 and KAFKA-20380.
>
> Release notes for the 4.2.1 release:
> https://dist.apache.org/repos/dist/dev/kafka/4.2.1-rc4/RELEASE_NOTES.html
>
> Please download, test and vote by Tuesday, May 19, 9pm PT.
>
> 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/4.2.1-rc4/
>
> * Docker release artifacts to be voted upon:
> apache/kafka:4.2.1-rc4
> apache/kafka-native:4.2.1-rc4
>
> * 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/4.2.1-rc4/javadoc/index.html
>
> * Tag to be voted upon (off 4.2 branch) is the 4.2.1 tag:
> https://github.com/apache/kafka/releases/tag/4.2.1-rc4
>
> * Documentation:
> https://kafka.apache.org/42/documentation.html
>
> * Protocol:
> https://kafka.apache.org/42/design/protocol/
>
> * Successful CI builds for the 4.2 branch:
> Unit/integration tests: https://github.com/apache/kafka/actions/runs/25717277218
> System tests: https://jenkins.opensource4you.tw/job/kafka-e2e/746/, https://jenkins.opensource4you.tw/job/kafka-e2e/747/, https://jenkins.opensource4you.tw/job/kafka-e2e/748/
>
> * Successful Docker Image Github Actions Pipeline for 4.2 branch:
> Docker Build Test Pipeline (JVM): https://github.com/apache/kafka/actions/runs/25728469988
> Docker Build Test Pipeline (Native): https://github.com/apache/kafka/actions/runs/25728486740
>
> Thanks,
> PoAn
>
> --
> 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 kafka-clients+unsubscribe@googlegroups.com.
> To view this discussion visit https://groups.google.com/d/msgid/kafka-clients/CAL6fUMRTp3Y7%2BEsbZftMQJQvotbSXop-DohkxN4h_di%2B7tSAQQ%40mail.gmail.com.
Re: [kafka-clients] [VOTE] 4.2.1 RC4
Posted by Lucas Brutschy via users <us...@kafka.apache.org>.
+1 (non-binding)
Verified on macOS arm64, JDK 17:
* GPG signatures and SHA512 checksums for source, binary, and
site-docs tarballs
* LICENSE/NOTICE present
* Built source with ./gradlew jar — BUILD SUCCESSFUL
* git tag 4.2.1-rc4 commit matches the shipped jar's
kafka-version.properties commitId
* KRaft quickstart: format --standalone, broker start,
topic/produce/consume
* KIP-1071 streams group: ran WordCountDemo with
group.protocol=streams; logs show StreamsGroupHeartbeatRequestManager
and counts aggregate correctly across rounds. Exercised
kafka-streams-groups.sh --list/--describe/--members/--state/--offsets/
--verbose; --reset-offsets correctly rejected while Stable, accepted
once Empty
* Docker images apache/kafka and apache/kafka-native: both start,
produce/consume works against each, commitId matches the tag
* Documentation, javadoc, protocol, release-notes, and GitHub tag URLs
all reachable
* Maven staging artifacts present with Last-Modified matching the rc4
tag date
* Did not rerun the full test suite locally; relied on the linked
Apache CI run
Thanks PoAn for running the release!
On Tue, May 12, 2026 at 2:14 PM PoAn Yang <ya...@gmail.com> wrote:
>
> Hello Kafka users, developers and client-developers,
>
> This is the second candidate for release of Apache Kafka 4.2.1.
>
> This is the first bug fix release for Apache Kafka 4.2 with fixes as described in the release notes. In the second candidate, it adds KAFKA-19851 and KAFKA-20380.
>
> Release notes for the 4.2.1 release:
> https://dist.apache.org/repos/dist/dev/kafka/4.2.1-rc4/RELEASE_NOTES.html
>
> Please download, test and vote by Tuesday, May 19, 9pm PT.
>
> 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/4.2.1-rc4/
>
> * Docker release artifacts to be voted upon:
> apache/kafka:4.2.1-rc4
> apache/kafka-native:4.2.1-rc4
>
> * 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/4.2.1-rc4/javadoc/index.html
>
> * Tag to be voted upon (off 4.2 branch) is the 4.2.1 tag:
> https://github.com/apache/kafka/releases/tag/4.2.1-rc4
>
> * Documentation:
> https://kafka.apache.org/42/documentation.html
>
> * Protocol:
> https://kafka.apache.org/42/design/protocol/
>
> * Successful CI builds for the 4.2 branch:
> Unit/integration tests: https://github.com/apache/kafka/actions/runs/25717277218
> System tests: https://jenkins.opensource4you.tw/job/kafka-e2e/746/, https://jenkins.opensource4you.tw/job/kafka-e2e/747/, https://jenkins.opensource4you.tw/job/kafka-e2e/748/
>
> * Successful Docker Image Github Actions Pipeline for 4.2 branch:
> Docker Build Test Pipeline (JVM): https://github.com/apache/kafka/actions/runs/25728469988
> Docker Build Test Pipeline (Native): https://github.com/apache/kafka/actions/runs/25728486740
>
> Thanks,
> PoAn
>
> --
> 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 kafka-clients+unsubscribe@googlegroups.com.
> To view this discussion visit https://groups.google.com/d/msgid/kafka-clients/CAL6fUMRTp3Y7%2BEsbZftMQJQvotbSXop-DohkxN4h_di%2B7tSAQQ%40mail.gmail.com.
Re: [VOTE] 4.2.1 RC4
Posted by Chia-Ping Tsai <ch...@apache.org>.
hi PoAn
Sorry to bring this up so late, but would you mind including KAFKA-20572 in the 4.2.1 ?
Best,
Chia-Ping
On 2026/05/12 12:14:21 PoAn Yang wrote:
> Hello Kafka users, developers and client-developers,
>
> This is the second candidate for release of Apache Kafka 4.2.1.
>
> This is the first bug fix release for Apache Kafka 4.2 with fixes as
> described in the release notes. In the second candidate, it adds
> KAFKA-19851 and KAFKA-20380.
>
> Release notes for the 4.2.1 release:
> https://dist.apache.org/repos/dist/dev/kafka/4.2.1-rc4/RELEASE_NOTES.html
>
> Please download, test and vote by Tuesday, May 19, 9pm PT.
>
> 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/4.2.1-rc4/
>
> * Docker release artifacts to be voted upon:
> apache/kafka:4.2.1-rc4
> apache/kafka-native:4.2.1-rc4
>
> * 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/4.2.1-rc4/javadoc/index.html
>
> * Tag to be voted upon (off 4.2 branch) is the 4.2.1 tag:
> https://github.com/apache/kafka/releases/tag/4.2.1-rc4
>
> * Documentation:
> https://kafka.apache.org/42/documentation.html
>
> * Protocol:
> https://kafka.apache.org/42/design/protocol/
>
> * Successful CI builds for the 4.2 branch:
> Unit/integration tests:
> https://github.com/apache/kafka/actions/runs/25717277218
> System tests: https://jenkins.opensource4you.tw/job/kafka-e2e/746/,
> https://jenkins.opensource4you.tw/job/kafka-e2e/747/,
> https://jenkins.opensource4you.tw/job/kafka-e2e/748/
>
> * Successful Docker Image Github Actions Pipeline for 4.2 branch:
> Docker Build Test Pipeline (JVM):
> https://github.com/apache/kafka/actions/runs/25728469988
> Docker Build Test Pipeline (Native):
> https://github.com/apache/kafka/actions/runs/25728486740
>
> Thanks,
> PoAn
>