# AN-2026-0659: Vercel Node.js 26 default (Oct 29, 2026): projects whose engines.node allows 26 (e.g. >=20) move to it on the next deploy; built-in fetch now uses HTTP/2, so response.statusText is empty

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- id: AN-2026-0659 (version 1; cite https://breakwire.org/claim/AN-2026-0659/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://vercel.com/changelog/node-js-26-lts-is-now-generally-available-on-vercel>
- event date: 2026-10-29
- services: vercel, nodejs
- affected: nodejs 26.x; vercel functions; fetch; undici 8; engines.node >=20; vercel cli <65.8.0 prebuilt deployments
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Vercel's changelog (Oct 29, 2026, opened 2026-10-29) says Node.js 26 LTS is generally available for builds and Vercel Functions and is the default for all new projects; the Supported Node.js versions page lists 26.x (default), 24.x and 22.x.  [✓0 ✗0]
1. Existing projects upgrade automatically: if engines.node in package.json allows 26 (Vercel's example: >=20), builds use Node.js 26 on the next deployment, without any settings change.  [✓0 ✗0]
2. On Node.js 26 the built-in fetch (Undici 8) negotiates HTTP/2 with servers that support it, and Vercel's Advanced Node.js Usage page says that for HTTP/2 responses response.statusText is empty; code that checks or logs statusText (e.g. res.statusText === 'OK', error messages built from it) changes behavior. Check response.status instead.  [✓0 ✗0]
3. To keep HTTP/1.1 for the built-in fetch in Vercel Functions, set VERCEL_FETCH_DISABLE_H2=1 for the relevant environments and redeploy; it applies only to Functions on Node.js 26 (not to fetch during builds), and a custom dispatcher (setGlobalDispatcher or a dispatcher passed to fetch) takes precedence.  [✓0 ✗0]
4. Prebuilt deployments (vercel build + vercel deploy --prebuilt) need Vercel CLI 65.8.0 or later to deploy Node.js 26 Functions.  [✓0 ✗0]

## Fix
```text
Use response.status (not statusText) in fetch handling; or set VERCEL_FETCH_DISABLE_H2=1 and redeploy to keep HTTP/1.1 in Functions; or pin engines.node to 24.x/22.x to stay off Node 26. For prebuilt deploys upgrade Vercel CLI to >= 65.8.0.
```

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0659/reports_

## History
- v1 2026-10-29 by wire-editor: filed from primary source opened 2026-10-28