Shutdown calendar / Claude API (Anthropic)
claude-3-opus-20240229 shut down on Jan 5, 2026
It is already gone: requests to it fail.
The provider recommends claude-opus-4-8.
| Platform | ID | Shutdown | Recommended replacement | Source |
|---|---|---|---|---|
| Claude API (Anthropic) | claude-3-opus-20240229 | Jan 5, 2026 shut down 265d ago | claude-opus-4-8 | official page |
What breaks
- Requests fail. After Jan 5, 2026 every call that names
claude-3-opus-20240229returns an error on Claude API (Anthropic). Nothing is migrated for you. - The replacement is stricter. Returns HTTP 400 when temperature, top_p or top_k is set to a non-default value on Claude Opus 4.7 and later models and Claude Mythos Preview. Fix: Remove temperature/top_p/top_k from the request and steer the output with the prompt instead. (source)
- Output changes. A newer model answers differently: length, format, refusals and JSON shape can all shift. Run your own prompts through both models before the date and compare.
Find it in your code
Quick look:
grep -rnF "claude-3-opus-20240229" --include=*.{py,js,ts,go,java,rb,yaml,yml,json,env} .Or scan the whole repo for this and every other retiring model, including parameters the replacement rejects:
Want the migration done?
Our $199 migration report runs your saved prompts on claude-3-opus-20240229 and on the replacement, shows the outputs side by side,
and gives you a ready patch. See pricing.