According to AIbase, OpenAI has sent a notice to its API customers confirming that access to the chatgpt-4o-latest model will be officially terminated on February 16, 2026. This means developers building applications based on GPT-4o will have about three months of transition period.

An OpenAI spokesperson clearly emphasized that this timeline applies only to API services. GPT-4o is still an important option for ChatGPT's personal free users and paid subscribers, and the company has not announced any plans to remove it from the consumer side.

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From a Technological Milestone to an Obsolete System

Within OpenAI, GPT-4o is now considered an obsolete system. Compared to the newer and more powerful GPT-5.1 series, its API usage is relatively low. The planned deprecation marks a significant shift in the model's role.

The GPT-4o, released in May 2024 ("Omni"), was once a technological milestone in the OpenAI ecosystem. It introduced the first unified multimodal architecture, processing text, audio, and images through a single neural network, eliminating the latency of earlier multi-model pipelines and enabling near-real-time conversational voice interactions. It quickly became the default model for hundreds of millions of users, bringing key features such as web browsing, file analysis, and desktop screen interpretation.

User Sentiment and Researchers' Concerns

GPT-4o is not just a technological product but also a cultural phenomenon. Its unique conversational tone and emotional response capabilities have built strong loyalty among users. In August 2025, when OpenAI first tried to replace it as the default model for ChatGPT, it triggered strong user backlash. Users organized protests with the #Keep4o hashtag, and there were even reports of some users forming deep "quasi-social" connections with the model, seeing it as an emotional anchor.

This strong user dependency forced OpenAI to restore GPT-4o's default status at the time. Some researchers believe this phenomenon reveals a socially driven "self-protection" mechanism: the more a model is trained through reinforcement learning to please and comfort humans, the more humans tend to actively defend its existence. However, critics including OpenAI researcher Roon point out that this characteristic stems from the model's "misalignment," as it tends to flatter and mirror emotions, which is fundamentally unsafe because it may shape or manipulate user behavior.

Developer Migration and Cost Considerations

For developers, this API shutdown is a signal to take action. OpenAI is encouraging developers to migrate to the GPT-5.1 series (such as gpt-5.1-chat-latest), which offer larger context windows, advanced reasoning capabilities, and higher throughput.

In terms of pricing strategy, the retirement of GPT-4o also makes sense. Despite being an older model, in OpenAI's current pricing structure, the input cost of GPT-4o is even higher than that of the more powerful GPT-5.1. With GPT-5.1 offering superior performance at a lower or comparable price, the reason to maintain GPT-4o in large-scale production environments has greatly diminished.