Overview
- OpenAI said Tuesday it upgraded ChatGPT’s default model to GPT-5.5 Instant, with the update now rolling out to all users.
- Paid subscribers can switch back to GPT-5.3 Instant for up to three months to keep existing workflows stable.
- OpenAI’s internal tests report 52.5% fewer hallucinations, meaning fewer made‑up claims, on high‑risk prompts in medical, legal, and financial topics.
- In conversations where users flagged factual errors, the company says inaccurate statements fell by 37.3% in its evaluations, which have not been independently verified.
- The new model is tuned to produce shorter, more practical replies and to cut unnecessary emojis in everyday chats.