ChatGPT's default model has been updated to GPT-5.5 Instant, a model that brings accuracy improvements with fewer hallucinations, especially in areas like medicine, law, and finance, according to OpenAI.

GPT-5.5 Instant is more capable at tasks like analyzing images, answering STEM questions, and choosing when to use web search to provide a better answer. Responses can also be personalized because GPT-5.5 Instant can better draw context from past chats, files, and Gmail, but this is currently limited to paid subscribers.

OpenAI says that responses are "tighter and more to-the-point without losing substance" and without eliminating ChatGPT's personality. It will provide the same information, but without unnecessary formatting, emojis, and follow-up questions.

All ChatGPT models are being updated with memory sources, which will show users the past chats, files, and other context that ChatGPT used to generate a response.

GPT-5.5 Instant is rolling out today to all ChatGPT users, and it is replacing GPT-5.3 Instant as the default model. While free users can access GPT-5.5 Instant, the new personalization features are limited to Plus and Pro users on the web. Personalization will expand to mobile soon, and it will roll out to Free, Go, Business, and Enterprise users in the coming weeks.

It's not yet clear when Apple Intelligence's ChatGPT integration will switch to GPT-5.5 Instant.