- - Breaking changes: payload serialization now occurs before onSend hooks, AJV configuration removed, default listen address switched to 127.0.0.1, avvio upgraded to v5, and Fastify iterator removed.
- - New features added: expose printRoutes, introduce basePath property, add request.id and onRoute hook, support ignoring trailing slashes, improve prefix handling, and return 400 for JSON body parse failures.
- - Multiple bug fixes (IPv6 URL formatting, logger serializer overrides, error object handling, body parsing optimizations) and extensive documentation updates across Getting Started, Plugins Guide, and ecosystem listings.
v0.40.0
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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.