On 2026-09-05, OpenAI announced that it has opened its new model, GPT-6 Astra, to Pro, Enterprise, and Business Premium users of ChatGPT Work and Codex. While availability via API has also begun, the rollout to Plus and Business plan users is expected to take several days.
Alongside the model deployment, Codex has been updated. The mechanism for handling context window limits has changed; instead of summarizing and compressing information when the limit is reached, the system now employs a method to maintain notes across windows. This improvement enhances the ability to retain information during long-duration sessions.
Source: GPT-6 Astra が Pro・Enterprise・API に登場、Anthropic は Claude の制限をリセット - Pasquale Pillitteri (Google News: OpenAI)