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Claude Sonnet 4.5 Is Not Retiring on September 29, 2026. Here Is Why

Anthropic lists Claude Sonnet 4.5, Haiku 4.5 and Opus 4.5 as Active. Their 2026 dates are floors Anthropic set, not retirements. What deprecation means.

What the table says, model by model

API model name Released State Deprecated Retirement
claude-sonnet-4-5-20250929 2025-09-29 Active None Not sooner than September 29, 2026 (floor)
claude-haiku-4-5-20251001 2025-10-15 Active None Not sooner than October 15, 2026 (floor)
claude-opus-4-5-20251101 2025-11-24 Active None Not sooner than November 24, 2026 (floor)
claude-opus-4-1-20250805 2025-08-05 Retired 2026-06-05 2026-08-05
claude-sonnet-4-20250514 2025-05-22 Retired 2026-04-14 2026-06-15
claude-opus-4-20250514 2025-05-22 Retired 2026-04-14 2026-06-15
claude-3-7-sonnet-20250219 2025-02-24 Retired 2025-10-28 2026-02-19
claude-3-5-haiku-20241022 2024-10-22 Retired 2025-12-19 2026-02-19
claude-3-haiku-20240307 2024-03-13 Retired 2026-02-19 2026-04-20

What's covered

  • Anthropic's four lifecycle states
  • What the table says, model by model
  • What the retired waves show
  • What to do

Full guide with every version, risk scores, and live updates: https://endoflife.ai/article-claude-model-retirements-2026

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