GPT-5.1: A smarter, more conversational ChatGPT

What changed

We’re upgrading the GPT-5 series with warmer, more capable models and new ways to customize ChatGPT’s tone and style. GPT-5.1 starts rolling out today to paid users.

Why it matters

A concrete addition to Practical AI: Tools, Models & Frameworks: it changes what's available to builders today rather than being general commentary.

How it compares

Related prior coverage to compare against:

• Retiring GPT-4o, GPT-4.1, GPT-4.1 mini, and OpenAI o4-mini in ChatGPT
• Introducing GPT-4o and more tools to ChatGPT free users
• The new ChatGPT Images is here

• Retiring GPT-4o, GPT-4.1, GPT-4.1 mini, and OpenAI o4-mini in ChatGPT similarity 0.23
• Introducing GPT-4o and more tools to ChatGPT free users similarity 0.23
• The new ChatGPT Images is here similarity 0.20