OpenAI Launches GPT-5.5 Instant as New Default ChatGPT Model
OpenAI replaced GPT-5.3 Instant with GPT-5.5 Instant as the default model for all ChatGPT users, citing a 52.5% reduction in hallucinated claims in internal evaluations. The update targets accuracy improvements specifically in high-stakes domains such as law, medicine, and finance, while preserving low-latency performance. For developers, the model is accessible via API as 'chat-latest'.
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