The potential conclusion of OpenAI's GPT-4 could actually be positive news. Here's the reasoning behind that.

      OpenAI has experienced numerous changes in recent weeks, with more on the horizon. While the AI company has not yet confirmed the release of its upcoming GPT-5 model, it is clearing the way for it by discontinuing support for other models in its portfolio. Recently, OpenAI announced the retirement of its GPT-4 model as of April 30. GPT-4 was one of the brand's most well-known and longest-standing large language models. However, the company has redirected its focus from its initial large language model technology towards its reasoning models and other innovations in recent months.

      The brand has also taken significant steps, such as introducing a new GPT 4.1 model family exclusively for developers through an API, while also indicating plans to retire the recently launched GPT-4.5 model and introduce the o3 and o4 reasoning models. Although not officially confirmed, these developments seem to accelerate the timeline for GPT-5's release.

      **GPT-4 History**

      OpenAI released GPT-4 in March 2023 as the model behind the ChatGPT Plus subscription option during the early days of the AI surge. This initiative was launched to meet the high demand for the chatbot, which had overwhelmed its servers. At this time, ChatGPT Plus subscribers gained access to GPT-4, while free users continued with the original GPT-3.5 model that OpenAI had initially introduced.

      OpenAI highlighted several enhancements between GPT-3.5 and GPT-4, such as an expanded context window from 2048 tokens to as much as 128k tokens. Notable upgrades for GPT-4 included the ability to upload images for analysis through text-based responses and more creative text outputs from detailed prompts. The GPT-4 model has seen multiple versions, including GPT-4 Turbo, GPT-4 Turbo with Vision, GPT-4o, and GPT-4o mini, with GPT-4o mini currently serving as the base model across all ChatGPT tiers.

      **Introduction of Reasoning Models**

      OpenAI began its journey of introducing reasoning models in December 2024 during its marketing campaign called the 12 Days of OpenAI. This event revealed several new advancements for the brand, with the rollout of its o1 reasoning model being a notable highlight. This introduction mirrored the public launch of its large language models and offered consumers an overview of this new form of AI. Reasoning models are better equipped for logical reasoning and can demonstrate the thought process behind AI outcomes, in contrast to large language models, which are trained on data to provide contextual answers. During the 12 Days campaign, OpenAI also introduced its $200 monthly ChatGPT Pro tier, making the o1 model exclusive to that pricing plan.

      Since then, OpenAI has unveiled its new o3 and o4-mini reasoning models, which offer enhanced performance in coding, math, and scientific tasks compared to the o1 model. These new models are available in the $20 ChatGPT Plus tier, while the o4-mini model is included in the free ChatGPT tier.

      **GPT-4.5 and the Turing Test**

      While OpenAI has shown enthusiasm for reasoning models, it has also continued to develop and release its large language models. The brand made headlines by launching GPT-4.5 in late February 2025, marking its largest AI model thus far. This technology was significant for its reduced hallucinations, a common challenge for AI models. It also demonstrated enhanced conversational and problem-solving abilities, alongside greater emotional understanding, capable of recognizing nuances in creativity for tasks such as writing and design. This model was accessible to ChatGPT Plus and ChatGPT Pro users.

      In early April 2025, reports indicated that GPT-4.5 successfully passed the Turing Test intelligence evaluation in a study at UC San Diego. During the test, participants had to determine which model was human and which was AI after five minutes of interaction. Researchers found that when the AI model was programmed to imitate a “geeky 19-year-old familiar with internet culture,” it was identified as human 73% of the time. Without a specific profile, it was recognized as human 36% of the time.

      The Turing test is pivotal as it allows researchers to explore the potential applications and ethical implications of AI in real time. The study concluded that the GPT-4.5 model enabled humans to engage in meaningful conversations with AI.

      However, OpenAI announced its decision to retire GPT-4.5 in mid-April, just months after its introduction. The company stated that it did not reach the “frontier level” of AI that it intended, with technology surpassing existing models. OpenAI plans to completely remove GPT-4.5 from its offerings, informing developers that they will have access to the API until July 14 and providing guidance to transition their projects to alternative APIs.

      **API Efforts**

      While GPT-4 may soon be retired, OpenAI has clarified that its API will remain available for developers