Home Computing News GPT-5.5 Instant is now ChatGPT's default model, and it promises significantly fewer hallucinations in medicine, law, and finance, shorter responses, and smarter personalization. OpenAI OpenAI has swapped out GPT-5.3 Instant for GPT-5.5 Instant as the default ChatGPT model, rolling the update out to all users starting today. The new model focuses on improving three things: accuracy, conciseness, and personalization. Less hallucination, less fluff OpenAI says the accuracy improvements are most notable in high-stakes subject areas. In internal testing, GPT-5.5 Instant produced 52.5% fewer hallucinated claims than its predecessor on prompts covering medicine, law, and finance, and 37.3% fewer inaccurate claims on conversations users had previously flagged for errors. GPT-5.5 Instant is starting to roll out in ChatGPT. It’s a big upgrade, giving you smarter, clearer, and more personalized answers in a warmer, more natural tone. And it’s also more concise, which we heard you wanted.…