OpenAI Ships GPT-5.5 Instant — and Admits 5.6 Was Already Running Inside It

GPT-5.5 Instant began rolling out to Pro and Plus users, but the more revealing detail is that a newer model had reportedly been live in production without users knowing.

OpenAI is rolling out GPT-5.5 Instant, with the company's @ChatGPTapp account describing it as 'very smart, very intuitive, and very fun to chat with' and confirming the release starts with Pro users before reaching Plus. On its own, that is an unremarkable incremental update in a release cadence that has become almost monthly. What it sits next to is more interesting.

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