GPT-5.3 Instant mini in ChatGPT

GPT-5.3 Instant Mini has been released in ChatGPT. It replaces GPT-5 Instant Mini as the fallback model users reach after hitting their rate limits for GPT-5.3 Instant. Compared with GPT-5 Instant Mini, GPT-5.3 Instant Mini feels more natural in conversation, with stronger writing and contextual awareness.