On 5 August 2026 Anthropic switched off claude-opus-4-1-20250805 in the API. Not deprecated, switched off: requests to that ID now return an error.
If anything of yours still points at the old identifier, it already stopped working. Here is where to move and where forgotten references usually hide.
Where to move
Anthropic points to claude-opus-4-8. In most cases the migration is a model-name swap, with no change to behaviour or request format.
If you would rather jump straight to the newest, claude-opus-5 shipped on 24 July. It is faster and more cost-efficient on the same work.
Where forgotten references hide
Changing the code is the easy part. The problem is that a model name rarely lives in one place.
Check:
- environment variables on every stage, including the staging box everyone forgets
- CI configuration and runner definitions
- dashboards and alerts where the model name is baked into a filter
- background jobs and schedulers that run weekly and therefore never caught your eye
- docs and examples in the repo, which a new developer will copy verbatim
Confirming you migrated fully
The honest check is grepping the whole repository for the old identifier, infrastructure files included:
grep -rn "opus-4-1" . --include="*.ts" --include="*.py" --include="*.yml" --include="*.yaml" --include="*.env*"
Then walk your hosting panel's secrets and variables separately. Grep will not reach those.
If production is already down
The failure happens at the API layer, not in your application, so your logs show a rejection from Anthropic rather than an exception in your own code. Change the model ID and restart, no rollback needed.
With several services, fix the ones closest to the user first and sweep background jobs on a second pass.
Not landing here again
Anthropic retires models on a schedule and warns ahead of time, usually a couple of months. Opus 4.1 was no exception: the notice went out on 5 June.
Two habits that remove the problem:
- Keep the model name in one constant or one environment variable, not scattered through the code.
- Watch the model deprecation page and set yourself a reminder a month before each date.
Through Claudexia
We expose stable model IDs through our gateway, so a version change on the provider side does not break your code. The available list is always on the pricing page, and the request format stays the same, both Anthropic Messages and OpenAI-compatible.
You can verify it works on a minimal balance: the minimum top-up is one dollar, and we add another for joining our channel.