Apache Flink 2.1.2 Release Announcement

May 11, 2026 - Sergey Nuyanzin

The Apache Flink Community is pleased to announce the second bug fix release of the Flink 2.1 series.

This release includes 45 bug fixes, vulnerability fixes, and minor improvements for Flink 2.1. Below you will find a list of all bug fixes 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 2.1.2 or higher.

Release Artifacts #

Maven Dependencies # 

<dependency>
  <groupId>org.apache.flink</groupId>
  <artifactId>flink-java</artifactId>
  <version>2.1.2</version>
</dependency>
<dependency>
  <groupId>org.apache.flink</groupId>
  <artifactId>flink-streaming-java</artifactId>
  <version>2.1.2</version>
</dependency>
<dependency>
  <groupId>org.apache.flink</groupId>
  <artifactId>flink-clients</artifactId>
  <version>2.1.2</version>
</dependency>

Binaries #

You can find the binaries on the updated Downloads page.

Docker Images #

PyPi #

Release Notes # 

    Release Notes - Flink - Version 2.1.2

Bug

  • [FLINK-35556] - Wrong constant in RocksDBSharedResourcesFactory.SLOT_SHARED_MANAGED
  • [FLINK-37266] - Python CLI arguments doesn't work in session mode
  • [FLINK-38399] - As long as the join key includes one of the indexes from the source, the join can be converted into a delta join
  • [FLINK-38486] - Harden shutdown of DefaultExpressionEvaluator
  • [FLINK-38567] - ForSt state backend error with GROUP BY and async state execution
  • [FLINK-38574] - Avoid reusing re-uploaded sst files when checkpoint notification is delayed
  • [FLINK-38585] - Pyflink's thread mode may not work when using shipped venv.zip archive as virtual env
  • [FLINK-38586] - ClassCastException when using Delta Join with lookup cache
  • [FLINK-38624] - Flink 2.1 Job Failure: Type Mismatch Exception in StreamPhysicalOverAggregateRule (TIMESTAMP(3) vs TIMESTAMP(3) ROWTIME)
  • [FLINK-38703] - ConcurrentModificationException in FineGrainedResourceManager during reporting metrics
  • [FLINK-38704] - Metrics reporter setup does not load Prometheus with correct configs/port
  • [FLINK-38750] - Validation of queries with functions erroneously invoked under select fails with StackOverflow
  • [FLINK-38797] - PyFlink CsvSchemaBuilder.set_null_value method missing return self
  • [FLINK-38815] - The debug log will print the sensitive information of data security cookie certification in task manager and jobmanager
  • [FLINK-38916] - MultiJoin produces incorrect results for OR join conditions when parallelism is greater than 1
  • [FLINK-38938] - Restore of SQL job with CURRENT_TIMESTAMP fails with CodeGenException
  • [FLINK-38951] - Upgrade pemja to 0.5.6
  • [FLINK-38986] - SSL connection failures in BlobClientSslTest / NettyClientServerSslTest with latest JDK versions
  • [FLINK-39015] - Fix MultiJoin RowData behaviour for HeapStateBackend
  • [FLINK-39017] - Flink WebUI Job graph node click interaction fails in Chrome 144+ (PointerEvents suppression)
  • [FLINK-39052] - ModuleNotFoundError: No module named 'pkg_resources'
  • [FLINK-39130] - Allow native types to be used for MetricConfig
  • [FLINK-39242] - Method getDataType does not exist error when getting columns from ResolvedSchema
  • [FLINK-39355] - Table program cannot be compiled for JSON_OBJECT
  • [FLINK-39360] - LIKE clause doesn't support some patterns
  • [FLINK-39371] - CurrentDatabase fails for some patterns
  • [FLINK-39394] - Job overview metrics (business/backpressure/data skew) are showing N/A when some nodes are finished
  • [FLINK-39395] - Add spotless upToDateChecking
  • [FLINK-39424] - Setting LIKE does not support default escape characters.

Improvement

  • [FLINK-37881] - Drop gosu in favour of Dockerfile's USER
  • [FLINK-38417] - Ensure attribute ordering when managing join attributes in JoinKeyExtractor
  • [FLINK-38445] - Create test plans to validate upsert keys
  • [FLINK-38914] - Redirect users to deeplink when visiting an outdated or master docs page (instead of stable)
  • [FLINK-38924] - Redirect users to documentation home page when encountering a 404
  • [FLINK-38925] - Update Matomo URL to the right domain
  • [FLINK-38955] - Add canonical tag to generated Javadoc and PyDocs
  • [FLINK-39139] - Update lz4-java to 1.10.3

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