Error with Next.js Learn Dashboard App in v15

Hello,

I was exploring the Next.js lessons to check for changes after the v15 release, but I encountered an error when running the latest version. This happens when following the instructions from the Next.js Learn Dashboard App chapter 10.

$ pnpm dev

> @ dev G:\Repos\nextjs-learn\nextjs-dashboard
> next dev --turbo -p 3737

G:\Repos\nextjs-learn\nextjs-dashboard\node_modules\.pnpm\next@15.0.0_react-dom@19.0.0-rc-cd22717c-20241013_react@19.0.0-rc-cd22717c-20241013__react@19.0.0-rc-cd22717c-20241013\node_modules\next\dist\server\config.js:241
            throw new CanaryOnlyError('experimental.ppr');
                  ^

CanaryOnlyError: The experimental feature "experimental.ppr" can only be enabled when using the latest canary version of Next.js.
    at assignDefaults (G:\Repos\nextjs-learn\nextjs-dashboard\node_modules\.pnpm\next@15.0.0_react-dom@19.0.0-rc-cd22717c-20241013_react@19.0.0-rc-cd22717c-20241013__react@19.0.0-rc-cd22717c-20241013\node_modules\next\dist\server\config.js:241:19)
    at loadConfig (G:\Repos\nextjs-learn\nextjs-dashboard\node_modules\.pnpm\next@15.0.0_react-dom@19.0.0-rc-cd22717c-20241013_react@19.0.0-rc-cd22717c-20241013__react@19.0.0-rc-cd22717c-20241013\node_modules\next\dist\server\config.js:843:32)
    at async Module.nextDev (G:\Repos\nextjs-learn\nextjs-dashboard\node_modules\.pnpm\next@15.0.0_react-dom@19.0.0-rc-cd22717c-20241013_react@19.0.0-rc-cd22717c-20241013__react@19.0.0-rc-cd22717c-20241013\node_modules\next\dist\cli\next-dev.js:189:14)

Node.js v20.11.1
 ELIFECYCLE  Command failed with exit code 1.

next.config.ts

import type { NextConfig } from "next";

const nextConfig: NextConfig = {
  experimental: {
    ppr: "incremental",
  },
};

export default nextConfig;

I installed the app with the following command:

npx create-next-app@latest nextjs-dashboard --example  "https://github.com/vercel/next-learn/tree/main/dashboard/starter-example" --use-pnpm

It’s great that Next.js v15 is available with the @latest tag, but this error occurred. I resolved the issue by adding the Next.js canary version. Currently, there’s no error with version 15.0.1-canary.3, but I’m not sure if this error is a permanent or just temporary. I thought it would still be worth informing you.

Thanks, and keep up the good work!

Thanks for reporting this! I let the Next.js team know so we can get chapter 10 updated.

I appreciate you sharing the workaround that solved it for you!

2 Likes

We have to update that repo’s Next.js version (or recommend to install canary), but just as a heads up: some of our experimental flags (like ppr or dynamicIO), requires to have the latest canary version to work, given they change often and are important changes

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