How much notice before an AI model shuts down: Anthropic's last five notices gave 60 to 62 days, OpenAI usually gives six months, and GPT-4o got 92 days

Anthropic's last five model retirement notices each gave developers 60 to 62 days before the shutdown, the minimum its deprecation page promises for publicly released models. OpenAI's notices usually gave six months, but its October 14 notice for GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini gave 92 days.

OPENAI

OpenAI's deprecations page dates 11 notices, from April to October 2026. Six gave 182 to 184 days, four gave 92 to 97 days and one, for gpt-5.4-cyber, gave 20. The page promises at least six months for generally available models and at least three months for specialized variants such as chat-latest and Codex models, unless safety or compliance concerns require a faster timeline. Preview models can go with as little as two weeks. The GPT-4 series notice (October 14, shutdown January 14, 2027) gives no reason for its 92 days. OpenAI recommends GPT-6 Luna in their place.

ANTHROPIC

Anthropic's page dates 10 notices since September 2024. The five since December 2025, for Claude Haiku 3.5, Claude Haiku 3, Claude Sonnet 4 and Opus 4, Claude Opus 4.1 and Claude Sonnet 4.5, each gave 60 to 62 days. The five before gave 63 to 189 days: Claude Opus 3 got 189 (notice June 30, 2025), and Claude 2, Claude 2.1 and Claude Sonnet 3 got 181.

GOOGLE

Google's page lists each model's release date and earliest shutdown date, but not when developers were told, so its notice can't be counted from the page.

HOW LONG MODELS LAST

From release to shutdown, past or scheduled, the 98 models with a dated release last a median of 410 days. By lab: OpenAI 507 days (36 models), Anthropic 427 (11) and Google 277 (51). Google's preview and experimental models last a median of 213.5 days (32 models), against 461 for its stable ones (19). The shortest was gemini-3.1-flash-lite-preview, 83 days from March 3 to May 25, 2026. No Anthropic model lasted less than a year: Claude Opus 4.1 and Claude Sonnet 3.7 were each shut down 365 days after the date in their snapshot ids.

CLAUDE SONNET 4.5

Snapshot dated September 29, 2025. Notice on September 30, 2026, and shutdown on November 30, 2026, 427 days after release, the Anthropic median. Anthropic recommends Claude Sonnet 5.5.

HOW WE COUNTED

From the three labs' own deprecation pages, read November 5, 2026. Notice is the days from a dated notice to its shutdown date, counted once per notice, so a notice covering several models counts once. Release is the date in the snapshot id for OpenAI and Anthropic (models without one are left out) and the listed release date for Google, which calls its shutdown dates the earliest possible. Every shutdown is on the calendar at artificialwatch.com/model-retirements, also as JSON, CSV and an .ics feed.