Apache Flink 1.12.4 Released

May 21, 2021 - Arvid Heise

The Apache Flink community released the next bugfix version of the Apache Flink 1.12 series.

This release includes 21 fixes and minor improvements for Flink 1.12.3. The list below includes a detailed list of all fixes and improvements.

We highly recommend all users to upgrade to Flink 1.12.4.

Updated Maven dependencies:


You can find the binaries on the updated Downloads page.

Release Notes - Flink - Version 1.12.4


  • [FLINK-17170] - Cannot stop streaming job with savepoint which uses kinesis consumer
  • [FLINK-20114] - Fix a few KafkaSource-related bugs
  • [FLINK-21181] - Buffer pool is destroyed error when outputting data over a timer after cancellation.
  • [FLINK-22109] - Misleading exception message if the number of arguments of a nested function is incorrect
  • [FLINK-22368] - UnalignedCheckpointITCase hangs on azure
  • [FLINK-22424] - Writing to already released buffers potentially causing data corruption during job failover/cancellation
  • [FLINK-22438] - add numRecordsOut metric for Async IO
  • [FLINK-22442] - Using scala api to change the TimeCharacteristic of the PatternStream is invalid
  • [FLINK-22479] - [Kinesis][Consumer] Potential lock-up under error condition
  • [FLINK-22489] - subtask backpressure indicator shows value for entire job
  • [FLINK-22555] - LGPL-2.1 files in flink-python jars
  • [FLINK-22557] - Japicmp fails on 1.12 branch
  • [FLINK-22573] - AsyncIO can timeout elements after completion
  • [FLINK-22577] - KubernetesLeaderElectionAndRetrievalITCase is failing
  • [FLINK-22597] - JobMaster cannot be restarted


  • [FLINK-18952] - Add 10 minutes to DataStream API documentation
  • [FLINK-20553] - Add end-to-end test case for new Kafka source
  • [FLINK-22470] - The root cause of the exception encountered during compiling the job was not exposed to users in certain cases
  • [FLINK-22539] - Restructure the Python dependency management documentation
  • [FLINK-22544] - Add the missing documentation about the command line options for PyFlink
  • [FLINK-22560] - Filter maven metadata from all jars