v4.2.3

Next generation Telemetry Agent for Logs, Metrics and Traces.

February 17, 2026

KNOWLEDGE BASE

Release Notes v4.2.3

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 v4.2.3.

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

What’s new ?

Fluent Bit v4.2.3 is a maintenance release focused on stability and bug fixes across multiple plugins. It includes fixes for Splunk and Windows Event Log input handling, Kubernetes and log-to-metrics filter cleanup paths, OpenTelemetry output gRPC status handling over HTTP/2, Stackdriver OAuth2 lifecycle cleanup, and AWS-related updates and test coverage improvements.


Core


  • plugin_proxy: enable event_type specification for proxy plugins (a36b225a7)
  • aws: additional cleanup and adjustments (091593301)
  • processor: properly handle numeric values in config map (527ca9fc9)
  • filter: validate value property (not null) (a2f64b982)
  • config_format: align cf_yaml dirname behavior with POSIX (54a36fbe0)
  • cmake: kafka: fix OAuth Bearer detection on Windows (9191f7079)
  • bin: add NULL checks and improve CONT signal handling in leaks mode (ab34c0ea3, bf74f1da2)

Libraries

  • No bundled library upgrades in this release.

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 March 24, 2026

Fluent Bit v5.0.0 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.