Changelog
The Claude Code changelog tracks new features, bug fixes, and breaking changes across releases.
Canonical sources
Section titled “Canonical sources”| Source | URL | Best for |
|---|---|---|
| Official changelog | https://code.claude.com/docs/en/changelog | Full release notes with descriptions |
| RSS feed | https://code.claude.com/docs/en/changelog/rss.xml | Subscribe to updates |
| GitHub CHANGELOG.md | https://github.com/anthropics/claude-code/blob/main/CHANGELOG.md | Raw changelog file, good for diffing |
Silent model migrations
Section titled “Silent model migrations”Claude Code occasionally migrates sessions to newer models automatically, without a visible notification. Known migrations:
- Fennec → Opus — internal alias
fennecwas remapped to Opus - Sonnet 4.5 → 4.6 — sessions using
sonnetalias were upgraded in-place
If you notice different behavior after an update and haven’t changed your config, a silent model migration may be the cause. Check your ANTHROPIC_MODEL env var or model setting in settings.json to pin a specific model version.
To pin a model:
export ANTHROPIC_MODEL=claude-sonnet-4-6Or in .claude/settings.json:
{ "model": "claude-sonnet-4-6"}Use full model IDs (not aliases like sonnet) to avoid being affected by future alias remappings.
Tombstoned commands
Section titled “Tombstoned commands”Some slash commands have been removed in past releases. They are kept in the docs as “tombstones” so you know they’re gone:
| Command | Removed in | Notes |
|---|---|---|
/vim | v2.1.92 | Removed entirely |
/pr-comments | v2.1.91 | Removed entirely |
If you see references to these commands in older docs or examples, they no longer exist.
This documentation
Section titled “This documentation”This local reference covers Claude Code CLI v2.1.x. It is a snapshot — not updated in real time. For the most current information, consult the official changelog linked above.