Which AI model became the default for all ChatGPT users in February 2026 after OpenAI retired six older models?

In February 2026, OpenAI officially transitioned its ChatGPT platform, making GPT-5.2 the default model for all users. This significant update, which took effect on February 13, 2026, also saw the retirement of six older models: GPT-4o, GPT-4.1, GPT-4.1 mini, OpenAI o4-mini, and the previously announced GPT-5 Instant and Thinking models. The move aimed to streamline the user experience and consolidate resources on OpenAI's most advanced artificial intelligence.

GPT-5.2, which was initially released in December 2025, represents a substantial leap in AI capabilities. It was engineered to deliver significant improvements in general intelligence, offering enhanced reasoning, superior long-context understanding, better coding abilities, and more advanced vision processing. Users can expect a more structured, reliable, and engaging conversational experience, with GPT-5.2 designed to handle complex, real-world tasks more effectively than its predecessors. It features an "Auto" system that can intelligently switch between "Instant" and "Thinking" modes to provide optimal responses, whether for quick queries or deep analytical work.

This strategic shift by OpenAI reflects a continuous effort to push the boundaries of AI performance and user satisfaction. The decision to retire older models was partly driven by evolving user behavior, as the vast majority of ChatGPT usage had already migrated to GPT-5.2. Furthermore, feedback from users, particularly regarding the conversational style and warmth of models like GPT-4o, directly influenced the development of GPT-5.1 and GPT-5.2, leading to improved personality and customization options within the newer models. By focusing on its flagship GPT-5.2, OpenAI reinforces its commitment to providing the smartest and most efficient AI tools available.