vercel/next.js · error

Minimum recommended TypeScript version is v5.1.0, older vers

Error message

Minimum recommended TypeScript version is v5.1.0, older versions can potentially be incompatible with Next.js. Detected: ${typescriptVersion}

What it means

Non-fatal warning from verifyAndRunTypeScript during next typegen / build: the locally detected TypeScript package version was compared with semver.lt against the 5.1.0 minimum. Older compilers can emit declarations incompatible with Next.js' generated types, so the check warns (but proceeds) naming the detected version.

Source

Thrown at packages/next/src/lib/verify-typescript-setup.ts:226

    const typeScriptPackage = getTypeScriptPackageInfo(dir)
    const typeScriptPath = useTypeScriptCli
      ? typeScriptPackage?.tscPath
      : typeScriptPackage?.apiPath

    if (!typeScriptPackage || !typeScriptPath) {
      missingDepsError(
        dir,
        deps.missing.length > 0
          ? deps.missing
          : [useTypeScriptCli ? typescriptCliPackage : typescriptApiPackage]
      )
    }

    const typescriptVersion = typeScriptPackage.version

    if (semver.lt(typescriptVersion, '5.1.0')) {
      log.warn(
        `Minimum recommended TypeScript version is v5.1.0, older versions can potentially be incompatible with Next.js. Detected: ${typescriptVersion}`
      )
    }

    // Reconfigure (or create) the user's `tsconfig.json` for them:
    await writeConfigurationDefaults(
      typescriptVersion,
      resolvedTsConfigPath,
      intent.firstTimeSetup,
      hasAppDir,
      distDir,
      hasPagesDir,
      strictRouteTypes
    )
    // Write out the necessary `next-env.d.ts` file to correctly register
    // Next.js' types:
    await writeAppTypeDeclarations({
      baseDir: dir,

View on GitHub (pinned to 89d017eac4)

Solutions

1. Upgrade TypeScript to v5.1.0 or newer: `npm install --save-dev typescript@latest`.

When it happens

Trigger: Thrown at packages/next/src/lib/verify-typescript-setup.ts:224 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of vercel/next.js@89d017eac4 (2026-08-19). Data as JSON: /api/errors/d24dd4aa11be93e1. Report an issue: GitHub.