Simon Willison: ChatGPT Voice Mode Runs on Much Older, Weaker Model — Knowledge Cutoff Still April 2024

Simon Willison·medium signal

Simon Willison highlighted (April 10) that OpenAI's ChatGPT voice mode still runs on a GPT-4o-era model with an April 2024 knowledge cutoff, far behind the text-based ChatGPT models. The observation underscores a non-obvious gap: users expect the voice interface to run on the smartest available model, but it uses a significantly weaker one. This matters for builders integrating voice: the capability ceiling is substantially lower than text-mode Claude or GPT-5.