# Fluent Bit v5.1.1 — Fluent Bit 5.1.1 - Product: Fluent Bit (https://whatsnew.fyi/product/fluent-bit) - Vendor: Fluent - Date: 2026-08-16 - Version: v5.1.1 - Original notes: https://github.com/fluent/fluent-bit/releases/tag/v5.1.1 - Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v5.1.1 What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog. Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'. --- - **fixed** — Fix persistent chunks issues without matching routes on hot reloading in in_storage_backlog - **fixed** — Address underflow of buffer size on startup in out_s3 - **fixed** — Ensure alignment of reading dword width in compat - **fixed** — Address stale failed tasks on dispatch in engine_dispatch - **fixed** — Fix incorrect pointer arithmetic in diskstats metric cache in in_node_exporter_metrics - **fixed** — Fix SIMD boundary for JSON string encoding in utils - **fixed** — Plug unfreed allocated memories on exceptions in stream_processor sp_stream - **fixed** — Invalidate TLS session before socket close in downstream - **fixed** — Fix storage limit eviction with 32 or more outputs in input_chunk - **added** — Support timestamp placeholder in out_file - **added** — Add auto_extract_timestamp parameter in out_splunk - **added** — Add hostname as primary field and runtime tests in out_logdna - **added** — Add config map to the plugin registration in plugin_proxy - **changed** — Display evicted logs on dropping chunks in input_chunk in_storage_backlog https://fluentbit.io/announcements/v5.1.1/ ##### What's Changed * packaging: improve package index tree URLs for release listing by @lecaros in https://github.com/fluent/fluent-bit/pull/12236 * in_storage_backlog: Fix persistent chunks issues without matching routes on hot reloading by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12239 * workflows: bump ossf/scorecard-action from 2.4.3 to 2.4.4 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12182 * workflows: bump actions/stale from 10.4.0 to 11.0.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12183 * workflows: bump github/codeql-action/upload-sarif from 4.37.3 to 4.37.4 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12229 * workflows: bump actions/checkout from 7.0.0 to 7.0.1 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12230 * workflows: bump reviewdog/action-shellcheck from 1.32.0 to 1.32.1 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12250 * workflows: bump reviewdog/action-actionlint from 1.73.0 to 1.73.1 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12248 * workflows: bump github/codeql-action/upload-sarif from 4.37.4 to 4.37.6 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12249 * downstream: invalidate TLS session before socket close by @edsiper in https://github.com/fluent/fluent-bit/pull/12278 * out_s3: Address underflow of buffer size on startup by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12266 * compat: Ensure alignment of reading dword width by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12276 * engine_dispatch: Address stale failed tasks on dispatch by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12254 * in_node_exporter_metrics: fix incorrect pointer arithmetic in diskstats metric cache by @ngillen in https://github.com/fluent/fluent-bit/pull/12255 * input_chunk: in_storage_backlog: Display evicted logs on dropping chunks by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12288 * utils: fix SIMD boundary for JSON string encoding by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12285 * stream_processor: sp_stream: Plug unfreed allocated memories on exceptions by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12277 * out_logdna: add hostname as primary field and runtime tests by @agup006 in https://github.com/fluent/fluent-bit/pull/11517 * maintenance: update v5.1 stable status by @edsiper in https://github.com/fluent/fluent-bit/pull/12290 * motd: v5.1 by @edsiper in https://github.com/fluent/fluent-bit/pull/12240 * release: update to 5.1.1 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/12238 * out_file: support timestamp placeholder by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12245 * out_splunk: Add auto_extract_timestamp parameter by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12143 * tests: core_routes: Handle limit of rlimit's soft limit by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11592 * plugin_proxy: add config map to the plugin registration by @iypetrov in https://github.com/fluent/fluent-bit/pull/12058 * input_chunk: fix storage limit eviction with 32 or more outputs by @terrorobe in https://github.com/fluent/fluent-bit/pull/12235 ##### New Contributors * @iypetrov made their first contribution in https://github.com/fluent/fluent-bit/pull/12058 * @terrorobe made their first contribution in https://github.com/fluent/fluent-bit/pull/12235 **Full Changelog**: https://github.com/fluent/fluent-bit/compare/v5.1.0...v5.1.1