claude-3-haiku-20240307 just started returning errors — here's what happened

If your code hits claude-3-haiku-20240307 and started failing yesterday, you're not alone. Anthropic retired Claude Haiku 3 on April 20, 2026. Retired, not deprecated — requests to the old model ID no longer complete. They return an error. This is a real deprecation cutoff that was announced 60 days