v4.2.4

Next generation Telemetry Agent for Logs, Metrics and Traces.

April 10, 2026

KNOWLEDGE BASE

Release Notes v4.2.4

Fluent Bit is a Fast and Lightweight Data Processor and Forwarder for Linux, BSD, Windows and macOS. We are proud to announce the availability of Fluent Bit v4.2.4.

Below is a detailed list of changes included in this release…

What’s new ?

Fluent Bit v4.2.4 is a maintenance release focused on stability and correctness. It fixes Kubernetes filter prefix handling, multiline metadata propagation, log-to-metrics memory management, OTEL scope key leaks in the content modifier processor, HTTP/2 request body size enforcement, and Avro format specification errors. The engine metric accounting for post-processors is also corrected.


Core


  • multiline: propagate metadata even on parse exceptions
  • processor_content_modifier: fix OTEL scope autogenerated key memory leak
  • http_server: enforce buffer_max_size limit for HTTP/2 request bodies
  • avro: fix specification errors in Avro format handling for Kafka output
  • engine: use effective post-processor counts when computing output metrics
  • dockerfiles: install minimum required components only

Libraries

  • monkey: upgrade bundled library to v1.8.8

Plugins


Contributors

On every release, there are many people involved doing contributions to different areas like bug reporting, troubleshooting, documentation and coding, without these contributions from the community, the project won’t be the same and won’t be in the good shape that it is now. So THANK YOU! to everyone who takes part of this journey!

Join us

We want to hear about you, our community is growing, and you can be part of it!, you can contact us at:

Latest Version

New release on July 3, 2026

Fluent Bit v5.0.9 is out!

Check out the Release Notes, read the Updated Documentation or jump directly to the Downloads Section.

We are part of a wide community, no vendor lock-in.