v4.0.1

Next generation Telemetry Agent for Logs, Metrics and Traces.

April 23, 2025

KNOWLEDGE BASE

Release Notes v4.0.1

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 v4.0.1.


What’s new ?


In v4.0 series, we have upgraded our internal dependencies and deprecated packages for older targets like Ubuntu 16.04, 18.04 and 20.04. In addition, due to Kafka library updates, we have disabled Kafka support for CentOS 7 and Amazon Linux 2.

Core


  • input_chunk: fix missing initialization in routes_mask (#10223) (PR #10224)
  • plugin_proxy: fixed memory leak (PR #10179)
  • config_format
    • yaml: fix double-free from freeing state before cleanup on exit. (#10199) (PR #10199)
    • fix SEGV from missing return check (PR #10216)
  • build
    • new FLB_KAFKA (default: on) option (PR #10195)
  • tests
    • internal: fuzzers: extend ctrace fuzzer (PR #10217)
  • mp: fix flb_mp_accessor_keys_remove for subkey siblings (PR #10013)
  • conf: parsers: fix istio-envoy-proxy parser regex (PR #10203)

Libraries

Plugins


Contributors

On every release, there are many people involved doing contributions on 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 Apr 23, 2025

Fluent Bit v4.0.1 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.