Apache Flink 1.20.3 Release Announcement

October 9, 2025 - Xuannan Su

The Apache Flink Community is pleased to announce the second bug fix release of the Flink 1.20 series.

This release includes 16 bug fixes, vulnerability fixes, and minor improvements for Flink 1.20. Below you will find a list of all bugfixes and improvements (excluding improvements to the build infrastructure and build stability). For a complete list of all changes see: JIRA.

We highly recommend all users upgrade to Flink 1.20.3 or higher.

Release Artifacts #

Maven Dependencies #

<dependency>
  <groupId>org.apache.flink</groupId>
  <artifactId>flink-java</artifactId>
  <version>1.20.3</version>
</dependency>
<dependency>
  <groupId>org.apache.flink</groupId>
  <artifactId>flink-streaming-java</artifactId>
  <version>1.20.3</version>
</dependency>
<dependency>
  <groupId>org.apache.flink</groupId>
  <artifactId>flink-clients</artifactId>
  <version>1.20.3</version>
</dependency>

Binaries #

You can find the binaries on the updated Downloads page.

Docker Images #

library/flink (official images)
apache/flink (ASF repository)

PyPi #

apache-flink==1.20.3

Release Notes #

    Release Notes - Flink - Version 1.20.3

Bug

[FLINK-37181] - Failed to validate Maven wrapper SHA-256 on MacOS with mvnw
[FLINK-37747] - GlobalCommitterOperator cannot commit after scaling writer/committer
[FLINK-38035] - Security Vulnerability in PyFlink Logging Mechanism (PythonEnvUtils.java)
[FLINK-38098] - When submitting a task with the flink run command, adding the -sae parameter will cause the task to be killed
[FLINK-38121] - Build python wheel on linux failed
[FLINK-38137] - RocksDB State Backend Null Serialization Causes NPE and Asymmetric (De)Serialization Logic
[FLINK-38143] - Pyflink flat YAML based config support is broken
[FLINK-38267] - Job cannot be recovered from unaligned checkpoint after rescaling when one task has multiple exchanges
[FLINK-38327] - NPE during recovery from file-merged checkpoint after FO
[FLINK-38332] - Upgrade pemja to 0.5.5
[FLINK-38347] - Checkpoint file-merging manager may delete the directory unexpectedly when some RPC messages lost
[FLINK-38370] - CommitterOperator does not checkpoint all pending committables

Improvement

[FLINK-37946] - correct the example sql on page Table API SQL EXPLAIN
[FLINK-38044] - [UI] upgrade runtime web Angular framework and related deps to lastest version

Technical Debt

[FLINK-37952] - Do not tar python wheel packages in GH Nightly workflow
[FLINK-38091] - Update japicmp configuration post 1.20.2