v4 will follow Fastify v4, with a few breaking changes:

• Remove fastify as a dependency, and move it to a peer dependency
• Remove deprecated APIs
  • routesDir
  • configure
• Implement log redaction as a Pino v7+ transport in a worker thread
• Update Sentry features (Add Sentry tracing #414)
• Add a story for error reporting using RFC-7807 (RFC-7807 for errors #415)