Node.js 20 is now fully supported for Builds and Vercel Functions. You can select 20.x in the Node.js Version section on the General page in the Project Settings. The default version for new projects is now Node.js 20.
Node.js 20 offers improved performance and introduces new core APIs to reduce the dependency on third-party libraries in your project.
The exact version used by Vercel is 20.11.1 and will automatically update minor and patch releases. Therefore, only the major version (20.x) is guaranteed.
Read the documentation for more.