BitcoinOpenAI Just Upgraded ChatGPT's Default Model—Here's What GPT-5.5 Instant Actually DoesadminMay 5, 2026 by adminMay 5, 202603 In brief GPT-5.5 Instant replaces GPT-5.3 Instant as ChatGPT’s default model starting today, rolling out to all users for free. The model produced 52.5% fewer...