- Added new configuration options: childLoggerFactory, IPv6 ::1 listening origin, and allowUnsafeRegex type definition.
- Fixed bugs in type inference for .code().send(), abort signal handling before server readiness, setNotFoundHandler typing, uppercase request header handling, and refined FastifyErrors documentation.
- Updated documentation: security policy, plugin await side effects, header size notes, and removed a deprecated client‑aborted function.
v4.20.0
Official Fastify changelog summary with source attribution, release tags, and community reactions.
Track this Fastify release note alongside related changelog updates, risky changes, and weekly digest signals from the developer community.
Verify the original release note
Every summary should remain traceable to the original changelog or release source.
Follow this in context
Turn this Fastify release note into a weekly digest for the tools you actually use.
Create digestMore Fastify changelog updates
Fix for two Fastify security advisories (GHSA‑w2qp‑rph6‑63g4 and GHSA‑3m5p‑2c4r‑xxw2).
Added per‑route logging for Google Cloud Functions and introduced `Reply.prototype.mediaType` for easier content‑type handling.
Fixed trailer state clearing when removing all trailers and corrected requestCompleted handling to use null instead of undefined.