Instaclustr for Apache Kafka® and Kafka ® Connect 4.1.1 are generally available

December 22, 2025 | By Varun Ghai

 

NetApp is today announcing the general availability of Instaclustr for Apache Kafka® 4.1.1 and Kafka® Connect 4.1.1 on the NetApp Instaclustr Managed Platform.

Apache Kafka 4.1 builds on the Kafka 4.0 milestone by continuing to strengthen the platform’s reliability, operability and security, while also enhancing newer capabilities. A full list of inclusions and changes can be found in the upstream release notes for Kafka 4.1.0 and Kafka 4.1.1, but we’ve highlighted a few prominent ones below.

 

What’s new in Kafka 4.1 (highlights)

  • Queues for Kafka (KIP-932) progresses to Preview: You can start evaluating queue-like consumption patterns. It is still not production-ready, but it is maturing and is intended to support additional workload patterns. So, if you have queue like workloads (task/work-item processing, high fan out worker pools, or use cases where consumer count must exceed partition count), Kafka 4.1 makes it easier to explore these patterns. Please refer to the Preview Release Notes on limitations and how to enable and use it. The Instaclustr support team will also be happy to provide any guidance needed.
  • New Kafka Streams rebalance protocol enters Early Access: Kafka Streams rebalance protocol (KIP-1071), built on the newer consumer group protocol foundations (KIP-848) aims to make Streams task assignment a more first class part of the Kafka protocol and shift more logic into the coordinator, improving how scaling and rebalances behave over time. You can start evaluating this capability, but it is not recommended for production use yet. If you’d like guidance on evaluation strategy or risk boundaries, our support team can help you plan a safe validation approach.
  • Support running multiple plugin versions (KIP-891): This important improvement for Kafka Connect supports running multiple versions of connector plugins (connectors, converters, transformations, predicates) making it easier to upgrade and roll back plugins without needing separate Connect clusters purely for plugin version isolation.

Kafka 4.1 also includes a variety of reliability and usability enhancements, such as:

  • Consistent error handling for transactions (KIP-1050) to make transactional client behaviour more predictable and robust.
  • An enhanced consumer shutdown API (KIP-1092) allowing applications to control whether a consumer explicitly leaves the group when shutting down.
  • Calling flush from send callbacks now raises an exception (KIP-1118), preventing a previously possible deadlock scenario.
  • Consumer group scaling improvements for rack-aware assignment on topology changes (KIP-1101), and bring consumer topic metric naming into alignment with how they’re for producer topic metrics (KIP-1109).

Note: for any features which have not been made generally available yet, for example, ones in Preview or Early Access, we recommend evaluating these in non production environments only, as these aren’t covered by our production SLAs. In this release, Queues and the new Streams Rebalance Protocol are not GA.

 

Upgrade guidance for NetApp Instaclustr customers

Kafka 4.x runs, by design, only in KRaft mode. If you are currently on Kafka 3.x with ZooKeeper, the recommended path is to upgrade to Kafka 3.9.x, migrate from ZooKeeper to KRaft, and then proceed to Kafka 4.1.1. In addition, before moving to Kafka 4.x, there are client side changes you will need to be aware of, which we’re previously document here.

Our general best practice advice is to try Kafka 4.1.1 in a non production environment to validate compatibility with your clients and workloads before considering using it in production.

 

Lifecycle and support

With each new Kafka release, we review and update the lifecycle states for older supported Kafka versions in line with our lifecycle policy. To ensure you get the full benefit of our support and SLAs, we recommend staying current with supported GA versions and planning to upgrade at least once a year. This page provides a list of all supported Kafka versions and their lifecycle states as well as timelines for future changes.

Note, as part of our review, and keeping in mind many Blocker and Critical severity issues which have been identified in Kafka 4.0.0 in the last few months, we have marked that version as Closed with immediate effort. If you have a cluster in Kafka 4.0.0, please reach out to our support team to coordinate an upgrade to Kafka 4.1.1.

For reference, here’s a list of some of the more severe issues which exist in Kafka 4.0.0 but which have been fixed in Kafka 4.1.1: KAFKA-19760, KAFKA-19504, KAFKA-19246, KAFKA-19383, KAFKA-19367, KAFKA-19171, KAFKA-19275, KAFKA-19192, KAFKA-19427 and KAFKA-19294.

 

Getting Started

For all other customers, if you’d like to upgrade to Kafka 4.1.1, please reach out to our support team to work through sequencing, compatibility checks, and rollout considerations. For customers wishing to try it on a new cluster, we’ve got documentation to help you get started.

And if you’re new to our managed service, it’s super easy to sign up and enjoy the benefits of a fully managed Kafka service with 24×7 technical support and industry-leading SLAs!