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OpenAI Legacy GPT and o-series snapshots

Shuts down October 23, 202660 days from today.

VendorOpenAI
What endsLegacy GPT and o-series snapshots
AnnouncedApril 22, 2026
ShutdownOctober 23, 2026
Notice given184 days
Replacementgpt-5.6-sol, gpt-5.6-terra, gpt-5.6-luna depending on model
SourceVendor documentation

What is affected

The largest single batch. Retires gpt-4 and gpt-3.5-turbo, plus fine-tuned models built on them, which cannot simply be repointed.

How to check whether this affects you

Search your codebase for the identifiers above. They commonly appear in environment variables and configuration files as well as in source, so grep your deployment config, not just your application code.

Find out before it breaks, not after

Stack Sunset watches the vendor announcement layer that dependency scanners miss — API sunsets, licence changes, pricing shifts — and tells you which of the things you depend on is about to stop working.

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