OpenAI releases GPT-5.5 Instant, a new default model for ChatGPT
OpenAI replaces GPT-3.5 Instant as ChatGPT's default model with GPT-5.5 Instant, a faster variant likely optimized for latency and cost.
Excerpt
The new GPT-5.5 Instant model will replace GPT-3.5 Instant as the default model for ChatGPT
Read at source: https://techcrunch.com/2026/05/05/openai-releases-gpt-5-5-instant-a-new-default-model-for-chatgpt/