Claude Code 2.1.316: Opus 4.8 Fast Mode Ends 30 November With No Fallback, Gateway Model Blocks Fixed

Verdict: update to 2.1.316 today, and if anything you run uses fast mode on Claude Opus 4.8, move it to Claude Opus 5.5 before 30 November. After that date those requests fail outright, with no fallback. Our Claude Code rating stays conditional: this release changes deadlines and admin behaviour, not the cost question behind the rating. Opus 4.8 keeps its recommended rating for review-heavy work in standard mode; only its fast mode is going away.

What happened

Anthropic's Claude Code changelog lists version 2.1.316, dated 31 October 2026. Four entries matter most:

• Opus 4.8 fast mode is deprecated. "Deprecated fast mode for Opus 4.8 as of October 30, 2026; it 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. Migrate to Opus 5.5 to keep the speedup."
• Managed settings no longer ask. "Changed server-managed settings for Team and Enterprise logins: settings fetched from Anthropic's API now apply without an approval prompt, and a stored copy that doesn't verify is refused."
• Gateway model blocks now hold. "Fixed the Claude apps gateway not checking every model a request names against availableModels, deniedModels and models; a request that names a blocked model now gets a 400 naming the field."
• A --restricted leak is closed. "Fixed --restricted sessions uploading files from outside the working directories when a Read allow rule covered them."

The same release adds:

• Pooled group budgets on the Claude apps gateway: "one monthly budget that a group's members share, on top of each member's own limit, set with pooled_budget on the spend limits admin API".
• CLAUDE_CODE_SUBAGENT_EFFORT, which sets the effort level subagents run at when nothing else names one.
• managed.policy_mode: layered, under which every matching gateway policy applies, not only the first.

Why it matters

• Fast mode on Opus 4.8 fails hard in 27 days. There is no silent downgrade to standard Opus 4.8, so scripts, CI jobs and agents that request fast mode on that model will start erroring on 30 November.
• The migration target is not drop-in. Our directory rates Opus 5.5 conditional: thinking cannot be turned off and forced tool use returns an error. Test your fast-mode workloads on it now, not on 29 November.
• Admins lose a checkpoint. If your Team or Enterprise rollout relied on users seeing an approval prompt for server-managed settings, that prompt is gone. Settings from Anthropic's API now apply directly.
• Model deny lists had a gap. Before this release, the gateway did not check every model a request named against its allow and deny lists. The changelog gives no CVE or advisory for this fix or the --restricted one, so vulnerability scanners will not flag older versions. You have to upgrade on your own initiative.

What changes for you

• Developers: search your configs and scripts for fast mode on Opus 4.8 and switch those calls to Opus 5.5 before 30 November.
• Gateway operators: if you rely on availableModels, deniedModels or models, treat any version before 2.1.316 as not enforcing them fully. Upgrade, then decide whether pooled budgets or layered policies fit your setup.
• Team and Enterprise admins: tell users that managed settings now apply without a prompt, so changes you push take effect immediately.
• Anyone using --restricted: upgrade, since earlier versions could upload files outside the working directories.

We have not tested 2.1.316 ourselves; everything above comes from Anthropic's changelog.

FAQ

Will fast mode on Opus 4.8 fall back to standard Opus 4.8 after 30 November? No. The changelog says those requests return an error and do not fall back.

Does standard Opus 4.8 go away too? No. Only fast mode on Opus 4.8 is being removed. Standard Opus 4.8 is not affected by this change.

Is there a CVE for the gateway or --restricted fixes? The changelog names none, so scanners will not flag older versions. Upgrade anyway.