Claude Code v2.1.68 Released — Opus 4.6 Default, ultrathink Keyword Returns

Claude Code v2.1.68 was released on March 4, 2026 (US time). This release primarily focuses on model default configuration changes and the reintroduction of the ultrathink keyword.

Key Changes

Opus 4.6 Becomes Default Model

Opus 4.6 is now the default model for Max and Team subscribers. Medium effort provides the best balance between speed and thoroughness for most tasks. Users can change this anytime using the /model command.

ultrathink Keyword Reintroduced

The previously removed “ultrathink” keyword has been reintroduced, enabling users to activate high effort for the next turn when needed. This allows switching to deeper thinking for complex tasks.

Opus 4 and 4.1 Removed

Opus 4 and Opus 4.1 have been removed from Claude Code on the first-party API. Users who had these models pinned will be automatically migrated to Opus 4.6.

Technical Details

• Medium effort is suitable for most tasks, offering optimal balance between speed and quality
• The /model command allows changing model and effort level at any time
• Users with older models (Opus 4/4.1) are seamlessly migrated to the new model

How to Update

Claude Code users can update to the latest version using:

claude update

For new installations, refer to the official documentation.