As reported by tygartmedia.com and MindStudio, Anthropic will retire claude-sonnet-4-20250514 and claude-opus-4-20250514 from its API on June 15, 2026 at 9 AM Pacific — three days from now. After the deadline, any API calls to those model strings will fail. The fix is a one-line change: claude-sonnet-4-20250514 migrates to claude-sonnet-4-6, and claude-opus-4-20250514 migrates to claude-opus-4-8. Anthropic notes that prompting styles, tool use conventions, and JSON response formats are stable across 4.x generations, making the transition low-risk for most teams. Consumer Claude.ai accounts and Claude Code managed environments handle model selection automatically and are not affected by the deprecation.