#model-update

OpenAI launched GPT-5.5 Instant as ChatGPT's new default model, replacing GPT-5.3 Instant. The update delivers 52.5% fewer hallucinations on high-stakes topics like medicine, law, and finance, along with more concise responses and enhanced personalization using Gmail and past conversations.

On March 3, 2026 (UTC), OpenAI said on X that GPT-5.3 Instant is rolling out to all ChatGPT users. Its linked product post details improvements in refusal behavior, web-grounded answer synthesis, and availability across ChatGPT and API.