Claude Code 2.1.316 deprecates fast mode for Opus 4.8, with removal on November 30

Claude Code v2.1.316, released October 30, 2026, per its release notes:

• Fast mode for Opus 4.8 is deprecated as of October 30 and will be removed on November 30, 2026. After removal, fast mode requests on Opus 4.8 return an error and do not fall back to standard Opus 4.8. The notes say to migrate to Opus 5.5 to keep the speedup.
• New settings: CLAUDE_CODE_DISABLE_ULTRATHINK turns the ultrathink keyword off; CLAUDE_CODE_SUBAGENT_EFFORT sets the effort level subagents run at when nothing else names one, instead of inheriting the session's; CLAUDE_CODE_DISABLE_LOOPED_CROSS_CERT_DROP keeps system cross-certificates that certify each other in a loop, for servers whose private CA needs one.
• Claude apps gateway: pooled group budgets (one monthly budget a group's members share, on top of each member's own limit, set with pooled_budget on the spend limits admin API); managed.policy_mode: layered, which applies every policy that matches a developer, each merged over the ones below it; guardrail.input_tagging on Bedrock upstreams. The gateway now checks every model a request names against availableModels, deniedModels and models, and answers a blocked one with a 400 naming the field.
• Behavior changes: server-managed settings fetched from Anthropic's API for Team and Enterprise logins now apply without an approval prompt, and a stored copy that doesn't verify is refused. In the VS Code extension, ultrathink now runs its turn at xhigh effort.
• Fixes include --restricted sessions uploading files from outside the working directories when a Read allow rule covered them, PowerShell hooks not blocking on exit code 2 in some commands, and shell commands left running after Claude Code exits on its own.

The release also adds cloud-session form cards, Claude Tag Slack fixes and a findings-by-severity card on the Code Review analytics page.