# Fastify SDK 2.0

Fastify, the fast and low overhead web framework for Node.js, has recently shipped Fastify v5. In order to support Fastify v5 a new major version of `@clerk/fastify` had to be released. With Clerk's Fastify SDK 2.0 comes full support for Fastify v5 and no breaking changes for the Clerk SDK itself.

If you're using Fastify and `@clerk/fastify`, you can update like so:

1. Follow the official [Fastify v5 migration guide](https://fastify.dev/docs/latest/Guides/Migration-Guide-V5/)
2. Install the latest version of `@clerk/fastify`
   ```shell
   npm install @clerk/fastify@latest
   ```
3. You're done! No further changes needed

`@clerk/fastify@^2.0.0` only supports Fastify v5 or later, if you want/need to continue using Fastify v4, please stick with `@clerk/fastify@^1.0.0`.