Node.js 26.13.0 'Lithium' Moves Node.js 26.x Into LTS Through April 2029, While the Node.js 27.0.0-alpha.0 Pre-Release Lists V8 15.6 and OpenSSL 3 as a Minimum

Overview

Node.js shipped two releases on consecutive days that sit at different points in its release pipeline. According to the Node.js 26.13.0 release post, dated 2026-10-28, the release “marks the transition of Node.js 26.x into Long Term Support (LTS)” under the codename ‘Lithium’. The Node.js 27.0.0-alpha.0.0.0 release post, dated 2026-10-29, covers an alpha of the next major line. It is a pre-release, and its notes list a V8 upgrade and a series of semver-major changes.

What Node.js 26.13.0 changes

The 26.13.0 post says Node.js 26.x “will continue to receive updates through to the end of April 2029.” It also says: “Other than updating metadata, such as the process.release object, to reflect that the release is LTS, no further changes from Node.js 26.12.1 are included.” The Herald previously reported on Node.js Security Releases 26.12.1, 24.22.1 and 22.23.4, which fix ten CVEs, four rated high, including a Brotli decoder out-of-bounds write.

For anyone moving from an older LTS line, the same post carries a note: “If you are updating from an earlier Long Term Support release (e.g. Node.js 24 or 22 or earlier) please note that since Node.js 25 the official binaries for Linux are linked against libatomic, which may need to be installed separately depending on your Linux distribution.”

What the 27.0.0-alpha.0 notes list

The alpha post says the V8 engine “is updated to version 15.6.75.13, up from 14.6 in Node.js 26.” Language features it lists as enabled by default are Math.sumPrecise(), Intl.Locale.prototype.variants, Iterator.prototype.join(), Iterator.prototype.includes(), Iterator.zip() and Iterator.zipKeyed(). Three further features are listed as experimental behind flags: import defer (—js-defer-import-eval), Immutable ArrayBuffer (—js-immutable-arraybuffer) and RegExp buffer boundaries (—js-regexp-buffer-boundaries).

Several V8-related changes affect existing applications, according to the same notes:

• Heap sizing. When —max-old-space-size is not set, “the default heap size limit is now half of the physical memory clamped between 256 MB and 4 GB, and memory held by Buffer and ArrayBuffer instances now counts toward the heap limit.” The notes say applications that relied on the previous defaults should set —max-old-space-size explicitly.
• Serialization. v8.serialize(), structuredClone() and postMessage() use a new format that older Node.js releases cannot read.
• WebAssembly. The notes say asm.js is no longer compiled to WebAssembly, and the —experimental-wasm- flags are renamed —wasm-.
• Heap snapshots. They include internal objects, numeric values and full script sources; the notes say taking one takes about twice as long and the file is about twice as large.

The post also lists V8 behavior changes, including that error.stack is no longer looked up through the prototype chain and that Array.prototype.sort() uses PowerSort for large arrays and remains stable. It adds that a full changelog of the V8 changes between 14.6 and 15.6 “will be shared soon.”

Other items in the alpha’s notable-changes list

Entries the post tags as semver-major include:

• build: require OpenSSL 3 or later, and remove the bundled FIPS provider build;
• crypto,https,tls: end OpenSSL engine support;
• domain: runtime-deprecate the module;
• fs: implement glob natively;
• http: increase the keepAliveTimeout default to 65 seconds, and make req.headers have a null prototype;
• http2: increase default window sizes;
• lib,src: remove the —no-experimental-websocket CLI flag;
• build: downgrade Intel macOS support to experimental;
• src,lib: add an —allow-env permission;
• deps: upgrade npm to 12.1.0;
• net: add an experimental net/promises API.

Entries tagged semver-minor in the post’s commit list include fs.mkstemp(), a zlib crc32c function, and “vfs: unflag.”

What We Don’t Know

• The alpha post does not give a date for a stable Node.js 27 release or for its own LTS promotion, and this article does not state one.
• The alpha notes say a full changelog of the V8 changes between 14.6 and 15.6 had not yet been published at the time of the post.