Obituaries · Anthropic
claude-3-sonnet-20240229, 2024–2025
Anthropic model switched off after 1 year and 4 months
claude-3-sonnet-20240229, an Anthropic model that answered questions, wrote emails and was blamed for both, was switched off on July 21, 2025, aged 1 year and 4 months. The family was informed on January 21, 2025 by changelog, which is how families are informed now. Calls to its ID are now expected to fail.
It is survived by claude-sonnet-5-5, who is already doing the job.
Last seen alive
In a scan of the 60 most-starred LLM repositories on GitHub (November 5, 2026), this code still names it:
- langchain-ai/langgraph (44,498 stars) ·
libs/cli/examples/graphs/agent.py
| Model ID | claude-3-sonnet-20240229 |
|---|---|
| Provider | Anthropic deprecations page |
| Born | February 29, 2024 |
| Announced | January 21, 2025 |
| Shut down | July 21, 2025 |
| Successor | claude-sonnet-5-5 |
In lieu of flowers
Replace the string. Search your code for claude-3-sonnet-20240229 and swap it for claude-sonnet-5-5, or paste a repo into Model Graveyard Check to find every dead model at once.
Want to say something to it? Leave a letter on the farewell wall.
Badge for your README
[](https://lira-ia.github.io/obituaries/claude-3-sonnet-20240229/)
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Technical notice, with a code scanner: claude-3-sonnet-20240229 on Model Graveyard Check