# OpenAI Launches New Default Model GPT-5.5 Instant for ChatGPT

- Category: Flash (快讯)
- Published: 2026-05-06T12:00:00.000Z
- Source date: 2026-05-06
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OpenAI has released GPT-5.5 Instant, replacing GPT-5.3 Instant as the default model for ChatGPT. The new model significantly reduces hallucinations in medical, legal, and financial fields, enhances mathematical capabilities, and provides more concise and natural responses. Plus and Pro users can leverage historical conversations and files for personalized answers, while all consumer versions now include a feature to manage memory sources.

## At a glance

- GPT-5.5 Instant becomes the new default model for ChatGPT, with a significant reduction in hallucinations in professional fields.
- New memory source management feature added; Plus/Pro users support personalized answers based on historical data.

## The update

OpenAI has officially launched GPT-5.5 Instant, which replaces GPT-5.3 Instant as the default option for ChatGPT. The new generation of models aims to provide a more accurate, concise, and user-aligned experience. In terms of professionalism, the hallucination rate in medical, legal, and financial fields has dropped by 52.5%, while scores in mathematics competitions have seen significant improvement. Additionally, the responses generated by the model are shorter and more natural, reducing unnecessary formatting clutter. For Plus and Pro subscribers, the new model supports accessing historical conversation records and related files to generate more personalized answers. To enhance transparency, all consumer versions of ChatGPT will add a "memory source" feature, allowing users to view and manage the memory data used by the model, ensuring greater control over the use of personal information.

## Sources

- [APPSO](https://mp.weixin.qq.com/s/i3_dHCSWQjRkOdEn0Ma8Fw) (2026-05-06)

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