Claude Code 2.1.316

Claude Code is retiring fast mode for Opus 4.8. It was deprecated on October 30, 2026, and will be removed on November 30, 2026. After that, fast mode requests will return an error rather than fall back to standard Opus 4.8. The changelog recommends migrating to Opus 5.5.

Version 2.1.316 also adds CLAUDE_CODE_SUBAGENT_EFFORT to set a default effort level for subagents, plus CLAUDE_CODE_DISABLE_ULTRATHINK to turn off the ultrathink keyword. For teams using the Claude apps gateway, pooled group budgets add a shared monthly budget alongside each member's own limit.