Kafka Monthly Digest: May 2026

Releases

4.3.0
 

Kafka brokers and clients

• New configuration to bootstrap new followers from the last tiered offsets instead of log start offsets. (KIP-1023)
• New mechanism to cordon log dirs and broker to help scaling and decommissioning. (KIP-1066)
• New configurations to control the delivery limit and record count locks of share groups. (KIP-1240)
• New metrics exposing the usage percentage of the retention limits per topic partition. (KIP-1257)
• Support for OAuth client assertion with the client_credentials grant type. (KIP-1258)
• Various group coordinator improvements. (KIP-1196, KIP-1251 and KIP-1263)
   

Kafka Connect

• Batch translation of consumer group offsets via the new RemoteClusterUtils.translateOffsets() method. (KIP-1239)
• New configuration to make MirrorMaker emit metrics in the new format. Note: From Kafka 5.0, metrics will only be emitted in the new format. (KIP-1280)

Kafka Streams

• Allow handling of GlobalKTable exceptions in ProcessingExceptionHandler. (KIP-1270) 
• Support for headers in state stores. (KIP-1271 and KIP-1285)

4.2.1

4.4.0

4.3.1

On May 26, Bill Bejeck volunteered to run the 4.3.1 release. The reason for this quick bugfix release is the discovery of a significant memory leak in Kafka Streams in 4.3.0 which can lead to OutOfMemory errors (KAFKA-20616). You can find the release plan in the wiki.
 

Kafka Improvement Proposals

• KIP-1333: Support log segments larger than 2 GB: Today, the log segment size is stored in Kafka as an int so log segments are limited to ~2GB in size. In very high throughput or long retention scenarios this limit can be problematic. This KIP proposes removing that limit allowing sizes up to Long.MAX_VALUE.
   

• KIP-1338: Structured MDC Context for Kafka Logging: This KIP proposes including Mapped Diagnostic Context (MDC) data into the logs emitted by all the Kafka components. This would make it easier for log analysis tools to parse and process Kafka logs. 
   

• KIP-1347: Overriding voter set on storage formatting: In dynamic KRaft quorum mode, the hostnames of the voters are persisted in the metadata log and this is what controllers use at startup to discover the current voters. One limitation is that if all DNS names change at the same time, for example this can happen in Kubernetes environments when renaming a DNS domain, then controllers can't bootstrap any longer as all the hostnames in the metadata log are now invalid. This KIP aims at resolving this issue by providing a tool to update the voters in the metadata log. 
   

• KIP-1352: Ranges and Range Aggregations in the Kafka Streams DSL: This KIP proposes adding event-centric aggregations, instead of usual time-centric, by basing them on record count and time (before and after an anchor) to the Streams DSL API.

Community Releases

• kroxylicious 0.21.0: Kroxylicious is an open source pluggable framework for writing network proxies that understand the Apache Kafka protocol. The new release adds support for automatic sidecar injection to transparently proxy traffic from applications. It also adds support for HAProxy PROXY Protocol and brings improvements to schema validation and AWS KMS support.
   

• Sarama 1.50: Sarama is a pure Golang Kafka client. This release brings a partitioner that is compatible with the Java client. It also updates the protocol version supported for group and offset fetch APIs.

Blogs

• A proof of concept for Routing
• Kafka’s Real Compression Problem Is Batch Depth
• Introducing Dimster, a performance benchmarking tool for Apache Kafka