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Instaclustr for Apache Kafka® and Apache Kafka® Connect 3.5.1 Are Now Available

Instaclustr is pleased to announce the immediate availability of Instaclustr for Apache Kafka® and Apache Kafka® Connect 3.5.1 on our Managed Platform. 

Kafka 3.5.1 follows the release pattern we introduced with Instaclustr for Kafka 3.3.1 and Kafka 3.4.1—it is generally available when used in ZooKeeper™ mode, but as a public preview when used in KRaft mode. The Kafka project provides an overview of the main new features of Kafka 3.5. 

Some features that we feel are important to highlight to our customers are: 

  • A fix for CVE-2023-34455 (which we talked about in our recent Security Advisory) has been made available with an update to the impacted snappy-java library. 
  • ZooKeeper to KRaft migration with no downtime is still available as an Early Access feature and hence not recommended for production use. KIP-866 explains the overall feature implementation planned. This is a list of features missing in KRaft mode. 
  • Rack aware partition assignment support has been extended to beyond what was made available with Kafka 3.4, to not include the in-built assignors. Read more about it on KIP-881. 
  • As part of KIP-710, enhancements to the distributed mode in dedicated MirrorMaker2 have been made to make it feature complete. Meanwhile, KAFKA-14021 implements support for exactly once semantics to MirrorSourceConnector. 
  • ZooKeeper has now been marked as deprecated, with its removal from Kafka planned for Kafka 4.   

More details on our Managed Kafka 3.5.1 release: 

  • Clusters being upgraded will be upgraded to Kafka 3.5.1 with ZooKeeper mode enabled. Note that clusters running the Public Preview version of Kafka 3.3.1 or Kafka 3.4.1 with KRaft mode cannot be upgraded. 
  • For new Kafka clusters being created with Kafka 3.5.1, at time of cluster creation you will have the option of selecting whether you’d like the cluster to be created with ZooKeeper mode or preview KRaft mode. If you don’t actively make a choice, ZooKeeper mode will be the default for a newly created cluster. 

Kafka 3.5.1 with KRaft mode is available only as a Public Preview due to current shortcomings—most notably a lack of full support for a mechanism for migrating ZooKeeper clusters to KRaft with no downtime. Support as per current project timelines is expected in Kafka 3.6. 

With the release of Kafka 3.5.1 on our managed platform, we will be updating the lifecycle states for our older supported Kafka versions to more restrictive lifecycle states as per our lifecycle policy shown in the table below. In summary, the typical lifecycle for Kafka versions is GA -> Deprecated -> Closed -> Legacy Support (if needed) -> EOL.  

We encourage customers on any non-GA Kafka versions to get in touch with us via our support portal and schedule a version upgrade. 

Kafka Version * 

Current Lifecycle  


      New Lifecycle State w.e.f. Nov 1, 2023 


until at least 

3.0.2 Closed Legacy Support December 31, 2023 
3.1.2 GA Closed February 29, 2024 
3.3.1 GA Deprecated April 30, 2024 
3.4.1 GA GA July 31, 2024 
3.5.1  GA August 31, 2024 

* Kafka versions which are currently in more restricted states than GA or closed are not listed. Dates when they will be transitioning to EOL are communicated directly to the few customers still using them. 

We encourage you to try your preferred Kafka version in your non-production environments first to confirm compatibility with your Kafka clients before using it in production environments.  

If you need any help spinning up new Kafka cluster or upgrading existing managed Kafka clusters, please feel free to get in touch with us via our Support website.