`fastify-socket.io` plugin referenced in docs is unmaintained on Fastify v5+

[xcfio]

Summary

The Fastify integration docs recommend using the fastify-socket.io plugin, but it only supports Fastify 4.x and has not been updated for Fastify v5.

• fastify-socket.io latest (v5.1.0) declares a peer dependency of fastify@"4.x.x" — see: Supports Fastify versions 5.x ducktors/fastify-socket.io#180
• Fastify v4 LTS ended June 30, 2025
• Fastify v5 is the current stable release

Impact

Developers following the docs and running Fastify v5 get a peer dependency conflict:

npm warn peer fastify@"4.x.x" from fastify-socket.io@5.1.0
npm warn Conflicting peer dependency: fastify@4.28.1

Suggested Fix

Either:

1. Update the docs to note the Fastify v4 limitation with a warning, or
2. Point to an alternative approach (e.g., attaching Socket.IO directly to the underlying http server from Fastify)

References

• Supports Fastify versions 5.x ducktors/fastify-socket.io#180
• https://fastify.dev/docs/latest/Guides/Migration-Guide-V5/