Quick answer
OpenAI says GPT-5.4 and GPT-5.4 mini retire from Codex on August 31, 2026 when a user signs in with a ChatGPT account. OpenAI directs users to replace GPT-5.4 with GPT-5.6 Terra and GPT-5.4 mini with GPT-5.6 Luna in saved settings, configurations, custom agents, and scheduled tasks. The notice does not change OpenAI API access or Codex sessions authenticated with an API key.
The retirement is limited to Codex with ChatGPT sign-in
OpenAI says GPT-5.4 and GPT-5.4 mini retire from Codex on August 31, 2026 for users who authenticate with a ChatGPT account. The notice applies across Codex settings that select those models, including workspace defaults and local or managed configuration. It is a Codex access change rather than a general retirement of both model IDs from every OpenAI product.
Sources: OpenAI Help Center, OpenAI
OpenAI names GPT-5.6 Terra and Luna as the replacements
The migration mapping is explicit: replace GPT-5.4 with GPT-5.6 Terra, and replace GPT-5.4 mini with GPT-5.6 Luna. OpenAI describes Terra as the balanced GPT-5.6 model for everyday work and Luna as the faster, lower-cost option for clear, repeatable tasks. These are recommended substitutions, not claims that the models produce identical outputs or use the same amount of reasoning and usage.
Sources: OpenAI Help Center, OpenAI
Update saved configuration before the old model IDs fail
Check workspace defaults, saved model settings, managed configurations, custom agents, and scheduled tasks for the model IDs gpt-5.4 and gpt-5.4-mini. OpenAI specifically tells ChatGPT-authenticated Codex users to change those references to gpt-5.6-terra and gpt-5.6-luna respectively. After editing a recurring workflow, run one representative task and review the result before relying on it unattended.
Sources: OpenAI Help Center, OpenAI
API access and API-key authentication are not part of this change
OpenAI says the August 31 retirement does not affect the OpenAI API or Codex when it is authenticated with a user's own API key. That distinction matters for developers who use the same model name in more than one environment: a ChatGPT-authenticated Codex configuration can require migration even when an API-based workflow is unaffected by this notice.
Sources: OpenAI Help Center, OpenAI
Verify the current model list in the Codex client you use
Model access can vary by Codex client, ChatGPT plan, workspace policy, managed requirement, and rollout state. Use the model picker or the /model command in your current client after updating a configuration. OpenAI's model guide recommends starting with the default model and increasing reasoning effort only when the task needs more planning or analysis.
Sources: OpenAI
This Codex change does not establish Chat AI availability
The announcement concerns OpenAI Codex and does not announce a model addition or removal in Chat AI. This article therefore marks Chat AI availability as not applicable and makes no claim that GPT-5.4, GPT-5.6 Terra, or GPT-5.6 Luna is available through Chat AI.
Sources: OpenAI Help Center
Frequently asked questions
What readers usually ask
Which models retire from Codex on August 31?
OpenAI says GPT-5.4 and GPT-5.4 mini retire from Codex when the user signs in with a ChatGPT account.
What should replace GPT-5.4 in a Codex configuration?
OpenAI directs users to replace GPT-5.4 with GPT-5.6 Terra.
What should replace GPT-5.4 mini?
OpenAI directs users to replace GPT-5.4 mini with GPT-5.6 Luna.
Does the GPT-5.4 Codex retirement affect the OpenAI API?
No. OpenAI says the notice does not affect the OpenAI API or Codex authenticated with a user's own API key.
Where should teams look for old GPT-5.4 references?
OpenAI names workspace defaults, saved model settings, managed configurations, custom agents, and scheduled tasks as places to update.
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