one thing I thought of is that OpenAI is presumably disappointed at the public reaction to GPT-5, so if they think their next model update is great they might want to call it 5.5 to hype it up.

What qualifies as 5.1, what if it's called 5o or o5 or 5.5 but effectively acts like a patch / general improvement

@lukalot a model called GPT-5.1

@JoshYou but not 5.1-mini or 5.1-nano if those are released separately