OpenAI to Retire Legacy Models: The Dawn of the GPT-5.2 Era

In a major strategic shift, OpenAI has announced that it will phase out several legacy models from the ChatGPT interface effective February 13, 2026. The affected models include GPT-4o, GPT-4.1, GPT-4.1 mini, o4-mini, and even the initial versions of GPT-5 (both Instant and Thinking).

While these models will no longer be available to general users via the ChatGPT web and mobile apps, OpenAI clarified that developers will still be able to access them through the API for their specific applications.

Bridging the "Emotional Gap"

The decision to remove these models follows a fascinating period of user feedback. OpenAI originally planned to retire older versions immediately upon the launch of GPT-5. However, many users expressed a preference for GPT-4o, noting that its responses felt "warmer" and more "human" compared to the initial GPT-5 release.

In response, OpenAI spent months refining its latest architecture. The resulting GPT-5.1 and GPT-5.2 iterations have significantly improved in both reasoning and personality, successfully capturing the "warmth" users missed. Current data confirms this success: the vast majority of users have transitioned to GPT-5.2, with a mere 0.1% still utilizing the legacy GPT-4o model.

• OpenAI's decision to remove older versions and focus on version 5.2 reflects the fact that AI in 2026 will have moved beyond simply "answering questions" (instant response) to fully engage in "deep thinking" (reasoning/thinking). Version 5.2 can simulate complex thought processes quickly enough that users don't perceive the lag experienced with older versions like o1 or o3.

• Interestingly, OpenAI has begun using Reinforcement Learning from Human Feedback (RLHF) techniques, emphasizing "emotional intelligence" (EQ), more in version 5.2 to address the issue of "coldness" or "overly robotic" – a major barrier that initially prevented people from abandoning GPT-4o.

• Maintaining older versions in the API is a key strategy for enterprises that have built legacy workflows around existing models. Detaching from ChatGPT reduces user confusion, but keeping it in the API preserves the customer base that demands stable output.

• "Cleaning up" the old model from the interface reduces maintenance burden. (Maintenance) and server-based processing allow OpenAI to dedicate its resources entirely to developing the next-generation model (which could be GPT-6 or another secret project). 

 

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Source: OpenAI