# Fastify v5.11.3

- Product: Fastify (https://whatsnew.fyi/product/fastify)
- Vendor: Fastify
- Date: 2026-08-08
- Version: v5.11.3
- Original notes: https://github.com/fastify/fastify/releases/tag/v5.11.3
- Permalink: https://whatsnew.fyi/product/fastify/releases/v5.11.3

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'.

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- **fixed** — Clear trailer state when removing all trailers
- **fixed** — Pass null instead of undefined to requestCompleted on success
- **fixed** — Recognize constructor-assigned built-in properties as decorator
- **fixed** — Reset lastIndex before testing global/sticky content-type RegExp parsers

##### What's Changed
* fix: clear trailer state when removing all trailers by @Ram-blip in https://github.com/fastify/fastify/pull/6845
* docs: document percent-decoded route params as untrusted input by @mcollina in https://github.com/fastify/fastify/pull/6903
* docs(errors): document what the default error handler sends by @basteez in https://github.com/fastify/fastify/pull/6894
* docs(readme): fix grammar and cjs capitalization by @minirang in https://github.com/fastify/fastify/pull/6899
* fix: pass null instead of undefined to requestCompleted on success by @lazerg in https://github.com/fastify/fastify/pull/6837
* docs(encapsulation): clarify nested plugin scopes by @jean-michelet in https://github.com/fastify/fastify/pull/6893
* chore: Bump fastify/workflows/.github/workflows/lock-threads.yml from 6.0.0 to 7.0.0 by @dependabot[bot] in https://github.com/fastify/fastify/pull/6916
* chore: Bump fastify/workflows/.github/workflows/nested-quality.yml from 6.0.0 to 7.0.0 by @dependabot[bot] in https://github.com/fastify/fastify/pull/6917
* fix: recognize constructor-assigned built-in properties as decorator … by @aquie00t in https://github.com/fastify/fastify/pull/6892
* fix: reset lastIndex before testing global/sticky content-type RegExp parsers by @zelinewang in https://github.com/fastify/fastify/pull/6846

##### New Contributors
* @minirang made their first contribution in https://github.com/fastify/fastify/pull/6899
* @lazerg made their first contribution in https://github.com/fastify/fastify/pull/6837
* @zelinewang made their first contribution in https://github.com/fastify/fastify/pull/6846

**Full Changelog**: https://github.com/fastify/fastify/compare/v5.11.2...v5.11.3