Codex App May 26, 2026 Changelog
What changed in Codex app, IDE extension & web May 26, 2026, released 2026-05-26 — explained in plain English.
TLDR
- Two older AI models (GPT-5.3-Codex and GPT-5.2) are no longer available to pick in the Codex app.
- You'll need to switch to a newer model like GPT-5.5, GPT-5.4, or GPT-5.4 mini.
- This only affects people logging in directly through ChatGPT, not developers using API keys (the behind-the-scenes codes apps use to connect).
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If you use Codex to write or debug code, the specific AI "brains" you can choose from just got an update. This matters if you have a favorite older model selected, because you'll need to switch to a newer, better one the next time you use the app.
Breaking changes
- If your current setup is locked to one of the two older models (GPT-5.3-Codex or GPT-5.2) through a ChatGPT login, it will break until you manually select a newer model.
This is our plain-language summary. Read the complete, official notes on the Codex App official changelog ↗.
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