OpenAI Retires GPT-4, Paving the Way for GPT-5 and New AI Advancements

OpenAI's GPT-4 Sunset and the Dawn of New AI Eras

OpenAI is undergoing significant changes, with a notable shift away from its established GPT-4 model to make way for future advancements, particularly the anticipated GPT-5. This strategic move involves retiring the GPT-4 AI model as of April 30, a decision that signals a broader transition in the company's AI development focus.

The Evolution of OpenAI's Models

OpenAI has been actively developing and releasing new AI models, including a new GPT 4.1 model family exclusively for developers via API. Simultaneously, the company is phasing out the recently launched GPT-4.5 model and introducing its o3 and o4 reasoning models. These developments suggest a concerted effort to accelerate the timeline for GPT-5's release.

GPT-4: A Landmark in AI

Launched in March 2023, GPT-4 powered the premium ChatGPT Plus subscription, offering enhanced capabilities over the earlier GPT-3.5 model. Key improvements included a significantly larger context window (up to 128k tokens), the ability to analyze uploaded images, and more creative text generation. Subsequent versions like GPT-4 Turbo, GPT-4 Turbo with Vision, GPT-4o, and GPT-4o mini have further refined these features, with GPT-4o mini now serving as the base model across all ChatGPT tiers.

The Rise of Reasoning Models

In December 2024, OpenAI introduced its reasoning models, starting with the o1 model, during its "12 Days of OpenAI" campaign. Unlike large language models that provide contextual responses based on training data, reasoning models excel at logical thinking and can articulate their thought processes. The o1 model was initially exclusive to the $200 per month ChatGPT Pro tier. More recently, OpenAI released the o3 and o4-mini reasoning models, boasting improved performance in coding, math, and science tasks. These are available in the ChatGPT Plus tier, with o4-mini also included in the free tier.

GPT-4.5 and the Turing Test

Despite its focus on reasoning models, OpenAI continued to develop its LLMs, releasing GPT-4.5 in late February 2025. This model was noted for reduced hallucinations, enhanced conversational and problem-solving abilities, and improved emotional intelligence in creative tasks. GPT-4.5 was made available to ChatGPT Plus and Pro users. In a significant development, a UC San Diego study indicated that GPT-4.5 passed the Turing Test, being identified as human by participants 73% of the time when given a specific persona.

However, OpenAI announced the retirement of GPT-4.5 in mid-April 2025, stating it did not meet the desired "frontier level" of AI. Developers have until July 14 to transition their projects from the GPT-4.5 API.

API Efforts and Future Directions

OpenAI continues to support its GPT-4 API for developers, with potential future applications in consumer-focused AI tools. Brands like Duolingo, Stripe, and Microsoft have already leveraged GPT-4. The GPT-3.5 Turbo API, which powered the initial ChatGPT launch, is also available, used by companies such as Snap Inc., Quizlet, Instacart, and Shopify.

New API offerings include GPT-4.1, GPT-4.1 mini, and GPT-4.1 nano, providing similar functionalities to GPT-4.5 at a lower cost. While not a "frontier level" advancement, GPT-4.1 offers performance updates over GPT-4o and knowledge up to June 2024. OpenAI is testing GPT-4.1 with various partners, highlighting its speed and cost-effectiveness.

Anticipating GPT-5

GPT-5 is highly anticipated, with many of OpenAI's recent efforts potentially culminating in significant improvements. While a specific launch date remains unconfirmed, 2025 is considered a likely year. Early indications suggested a May or summer release, but the introduction of reasoning models may have shifted this timeline. CEO Sam Altman has hinted at potential changes in AI model naming conventions before GPT-5's release.

GPT-5 is expected to be a "frontier level" model, surpassing GPT-4. Key features may include autonomous AI agents capable of independent task execution and the ability to select the optimal AI model based on user queries. Both free and paid ChatGPT users will have access, with subscription tiers offering more advanced features.

Related Developments and Future Outlook

OpenAI is also planning to make its "Deep Research" function available to free-tier ChatGPT users, allowing AI agents to conduct extended research tasks independently. This feature was previously exclusive to paid subscribers.

In a recent move, OpenAI halted free GPT-4o image generation after users created viral trends, such as Studio Ghibli-style images, highlighting the need for more controlled AI image generation. Meanwhile, competitors like Nvidia are advancing GPU technology with chiplet designs for future architectures, signaling a competitive landscape in AI hardware.

Conclusion

OpenAI's strategic shifts, including the retirement of GPT-4 and the development of reasoning models and GPT-5, underscore a dynamic and rapidly evolving AI landscape. The company's focus on enhancing model capabilities, expanding accessibility, and exploring new AI paradigms like autonomous agents positions it at the forefront of AI innovation.