- Added new features: decorator warning and custom error schema handling.
- Fixed schemaErrorFormatter binding and exposed instance.errorHandler typings; updated documentation and ecosystem examples (healthcheck, reply lifecycle).
- Bumped yup dependency versions and tracked renaming of Fastify error properties.
v3.9.0
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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.