v2.1.15 Claude Code Release Notes

Jan 21, 2026

Claude's Analysisby Sonnet 4.6

npm installs now show a deprecation warning — switch to claude install. React Compiler improves UI perf; MCP server timeout no longer causes UI freezes.

Changes

Total Changes (vs Average)

0.2×

Version Type

Patch

Release Focus

Mixed

Day Since Prior Release

Release # This Month

#15 of 26

Bug Fix Ratio

50%

Post-Release Edits

+1−1

Change Category

Ecosystem Impact

MCP reliability has been a recurring focus — fixes appeared in 4 of the last 10 releases. The stdio timeout fix here, which prevents zombie child processes from locking the UI, continues a pattern of hardening the MCP runtime layer across the 2.1.x series.

Key Themes

1Installation Channel Migration|3Reliability & UI Performance

May Help If You've Noticed

You installed via npm and are now seeing a new deprecation notice — it's intentional, time to switch to claude install.

Added1 change

•Added deprecation notification for npm installations - run claude install or see https://code.claude.com/docs/en/setup for more options

Improved1 change

•Improved UI rendering performance with React Compiler

Fixed2 changes

•Fixed the "Context left until auto-compact" warning not disappearing after running /compact
•Fixed MCP stdio server timeout not killing child process, which could cause UI freezes

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v2.1.15 Claude Code Release Notes

Jan 21, 2026

Claude's Analysisby Sonnet 4.6

Full Analysis

npm installs now show a deprecation warning — switch to claude install. React Compiler improves UI perf; MCP server timeout no longer causes UI freezes.

Changes

Total Changes (vs Average)

0.2×

Version Type

Patch

Release Focus

Mixed

Day Since Prior Release

Release # This Month

#15 of 26

Bug Fix Ratio

50%

Post-Release Edits

+1−1

Change Category

Ecosystem Impact

Key Themes

1Installation Channel Migration|3Reliability & UI Performance

May Help If You've Noticed

You installed via npm and are now seeing a new deprecation notice — it's intentional, time to switch to claude install.

Added1 change

•Added deprecation notification for npm installations - run claude install or see https://code.claude.com/docs/en/setup for more options

Improved1 change

•Improved UI rendering performance with React Compiler

Fixed2 changes

•Fixed the "Context left until auto-compact" warning not disappearing after running /compact
•Fixed MCP stdio server timeout not killing child process, which could cause UI freezes

v2.1.15 Claude Code Release Notes

Changes in Claude Code v2.1.15

Added1 change

Improved1 change

Fixed2 changes

v2.1.15 Claude Code Release Notes

Changes in Claude Code v2.1.15

Added1 change

Improved1 change

Fixed2 changes