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DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

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Claude Code v2.1.242

Binary updates can download a zstd-compressed build

You'll notice
Useful2 Signal2
Updater

Updates can arrive as a compressed build, so downloads get smaller with no setting to change.

What

The updater can now fetch a compressed build and decompress it locally, cutting download size. There is no client setting: it happens when the release channel's update manifest publishes a checksum and size for your platform, so it can be enabled per platform without shipping a new Claude Code.

Details
  • The updater fetches a compressed manifest alongside the normal one. When it supplies a 64-character hex checksum for your platform and a positive size, it downloads the .zst variant, streams it through a zstd decoder, enforces the manifest's decompressed size as a hard cap mid-stream, and verifies the sha256 of the compressed bytes.
  • Any failure (missing fields, checksum mismatch, size overrun, a rejected zstd frame) falls back silently to the uncompressed URL and records update_download_zst_fallback.
  • Successful downloads now report a compressed field on tengu_binary_download_success.
  • Manifest fetches now retry when the connection drops.
Evidence

Decompressed binary exceeds the manifest size of , Decompressed binary larger than manifest size

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Related

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

See this entry in the whole of v2.1.242 →