On November 12, 2025, OpenAI upgraded its ChatGPT-5 AI model with the “warmer” and “more intelligent” GPT-5.1 Instant model, as well as an easier-to-understand GPT-5.1 Thinking model.
ChatGPT-5.1: Overview
The company stated that GPT-5.1 Instant was its most popular model, although the GPT-5.1 Thinking model was better calibrated to address both basic and complicated inquiries, allowing for both rapid and delayed responses dependent on context.
OpenAI also stated that GPT-5.1 will provide a “smarter, more conversational ChatGPT” OpenAI CEO Sam Altman praised the latest releases, noting that users may also customise the AI models to meet different modes and communication styles.
“GPT-5.1 is released! It’s a good enhancement. I really like the improvements in instruction following and flexible thinking. The intelligence and style upgrades are also welcome,” Altman wrote on X (formerly Twitter) on Thursday, adding, “We’ve also made ChatGPT more customizable. You can use the presets (Default, Friendly, Efficient, Professional, Candid, or Quirky) or customise it yourself.”
OpenAI gave samples of the new models’ replies to prompts and contrasted them to those generated by the previous GPT-5 model. For example, while responding to a stressed-out user, GPT-5 provided relaxation suggestions, but GPT-5.1 instantly greeted the user by name and empathised with their recent experiences before providing comparable tips.
“For the first time, GPT‑5.1 Instant can use adaptive reasoning to decide when to think before responding to more challenging questions, resulting in more thorough and accurate answers, while still responding quickly,” according to a blog post from OpenAI.
GPT-5.1 Thinking also utilised a casual conversational language to communicate a technical idea.
GPT-5.1 Instant and Thinking are now available to paying users (Pro, Plus, Go, and Business subscriptions) before reaching free and logged-out users. The deployment will take place gradually over the next several days, with OpenAI stating that it will give customers enough time to convert to a new model before eliminating an older one.
This was previously a source of contention for the firm when it debuted the GPT-5 model, with many users going to social media to express their nostalgia for prior models that felt “warmer” and more “friendly.” Others were dissatisfied with a quick model update, stating that they did not have enough time to transfer their projects or modify their process.
Altman accepted the issue, but noted that many ChatGPT users had strong emotional relationships to certain AI models.
“GPT‑5 (Instant and Thinking) will remain available in ChatGPT under the legacy models dropdown for paid subscribers for three months, so people have time to compare and adapt at their own pace,” the manufacturer stated.
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