Fluent Bit Maintenance Policy
January 6, 2026 · View on GitHub
This document outlines the maintenance strategy and version support for Fluent Bit.
Active Branches and Maintainers
| Branch | Version | Status | Maintainer | Notes |
|---|---|---|---|---|
master | v5.0 (development) | Active development | Eduardo Silva | All new features and bug fixes land here first |
4.2 | v4.2.x | Stable | Eduardo Silva Hiroshi Hatake (@cosmo0920) | Current stable release series. Active development and updates. May receive minor enhancements in addition to fixes. |
4.1 | v4.1.x | Maintenance only | Hiroshi Hatake (@cosmo0920) | Critical fixes and safe backports only. Maintained until February 28, 2026 |
Maintenance Policy
Active development is currently on Fluent Bit v5.0 (tracked in the master branch). The v4.2 branch is the current stable release series and receives active updates. Previous release lines enter maintenance mode after the next major/minor release.
Accepted Changes for Maintenance Branches
- ✅ Security patches (see SECURITY.md for security update timelines)
- ✅ Critical bug fixes
- ✅ Low-risk enhancements that unblock adoption (e.g., OpenTelemetry improvements, performance tuning)
⚠️ All changes must first be merged into
masterbefore being cherry-picked into maintenance branches by the maintainer.
Maintenance releases continue on an as-needed basis depending on urgency and impact.
v4.2 Stable Series
v4.2 is the current stable release series and receives active development, bug fixes, and security updates. This is the recommended version for production use.
v4.1 Maintenance
v4.1 has entered maintenance mode, now maintained by Hiroshi Hatake (@cosmo0920), a long-time Fluent Bit contributor and core developer.
v4.1 will receive security updates and critical fixes until February 28, 2026 (as specified in SECURITY.md).
v4.0 Maintenance
v4.0 reached End-of-Life (EOL) on December 23, 2025 and is no longer maintained. No further security patches or bug fixes will be provided for this version line.
How to Contribute to Maintained Versions
If you're submitting a fix or feature relevant to a stable or maintenance branch (v4.2 or v4.1):
- Open your PR against the
masterbranch - Add a note in the PR or issue:
Target: v4.2orTarget: v4.1 - Tag the branch maintainer to request backport consideration:
- For v4.2: @edsiper @cosmo0920
- For v4.1: @cosmo0920
Note: v4.0 is End-of-Life and no longer accepts backports. For security-related issues, please follow the process outlined in SECURITY.md.