Node.js 26.1.0 Released with Temporal API Enabled by Default

Developers using the JavaScript runtime now have a new major release: the 26 series.

Node.js 26.0.0 introduced the long‑awaited Temporal API, which is now available without an experimental flag. The API offers richer time‑zone, calendar, duration, and instant handling, addressing long‑standing complaints about the built‑in Date object. Example usage:

// Old style, month index starts at 0 and time‑zone errors are easy
const d = new Date(2026, 4, 6);

// New Temporal API
const date = Temporal.PlainDate.from('2026-05-08');
const next = date.add({ days: 30 });
const zoned = Temporal.ZonedDateTime.from('2026-05-08T10:00[Asia/Shanghai]');

From version 26 onward you can call Temporal.Now.plainDateISO() directly. For pure Node.js server code this is a good migration point, although universal (isomorphic) code that also runs in browsers may still need dayjs for now.

V8 upgraded to 14.6 with new language features

The bundled V8 engine is now version 14.6.202.33, released alongside Chromium 146. Two TC39 proposals land in this release: the Upsert proposal adds setUpsert (exposed as getOrInsert()) and setInitialize (exposed as getOrInsertComputed()), simplifying common patterns for reading or initializing values. The iterator‑sequence proposal introduces iterator‑sequence, which can merge multiple iterators into a single sequence (e.g., Map, WeakMap, Iterator.concat()).

The NODE_MODULE_VERSION constant is bumped to 147, meaning native addons compiled for earlier versions must be rebuilt.

Undici 8 powers the built‑in HTTP client

The built‑in HTTP client, which underlies the global fetch(), Request, and Response APIs, is now based on Undici 8.0.2. Undici 8 brings many changes, including HTTP/2 handling, revised connection‑pool strategies, and updated error object formats. When upgrading, review the Undici changelog for breaking changes in Pool, Agent, and Dispatcher.

Deprecations that require code review

Several long‑standing APIs have been removed in the 26 series. Calls to http.Server.prototype.writeHeader() must be replaced with writeHead(). The internal stream modules _stream_wrap, _stream_readable, _stream_writable, _stream_duplex, _stream_transform, and the TypeScript flag _stream_passthrough have been removed, as has the experimental --experimental-transform-types flag. Runtime deprecations now emit warnings for module.register(), stream‑related DEP0201, and crypto‑related DEP0203/DEP0204.

Build and platform changes

Compiling Node.js from source now requires GCC 13.2 or newer and no longer supports Python 3.9. The Windows SDK version is upgraded to 11. Maglev, V8’s middle‑layer optimizing compiler, is enabled on Linux s390x. Platform support has been expanded: Power 9 (AIX/IBM i) is now officially supported, and Maglev runs on IBM z series hardware, improving performance on those architectures.

Other notable updates

The KeyObject API now supports raw key formats. The bundled SQLite integration enables percentile extensions. ICU is updated to 78.3, libuv to 1.52.1, and a V8 array‑index hash‑collision vulnerability (CVE‑2026‑21717) is fixed.

Conclusion

Node.js 26 is less a radical overhaul than a “clean‑up, speed‑up, and finish” release. Temporal, V8 14.6, and Undici 8 are incremental upgrades, while the deprecation list paves the way for the next version‑number revolution. The real turning point will be version 27, with its new LTS cadence, year‑based versioning, and an Alpha channel for early adopters.