OpenAI to Shut Down GPT-4.5 and GPT-4o—What Devs Need to Know Now

OpenAI is deprecating GPT-4.5, GPT-4o, o1, and o3-mini by mid-2025. Devs must switch to GPT-4.1, o3, or o4-mini to avoid workflow disruptions.

In the fast-evolving landscape of artificial intelligence, OpenAI continues to refine its offerings to deliver more efficient and capable models. As part of this strategy, OpenAI and GitHub Copilot have announced the deprecation of several models, including o1, GPT-4.5, o3-mini, and GPT-4o, effective in mid-2025. This move has sparked discussions among developers, with some expressing concern over workflow disruptions. This article explores the details of these deprecations, their implications, and how developers can prepare for a seamless transition, providing actionable insights for those relying on OpenAI’s API and GitHub Copilot.

Understanding the Deprecation Schedule

The deprecation process is well-documented, with clear timelines to help developers adapt. According to GitHub’s changelog, GPT-4.5 will be removed from GitHub Copilot and Copilot IDE model pickers by July 7, 2025, with GPT-4.1 recommended as the replacement. OpenAI’s API will also phase out GPT-4.5 Preview by July 14, 2025, as confirmed in an April 2025 announcement. While specific dates for o1, o3-mini, and GPT-4o deprecations in GitHub Copilot were not detailed, they are slated for removal around the same period, with o3 and o4-mini suggested as alternatives for o1 and o3-mini, respectively.

OpenAI’s decision to deprecate these models aligns with its focus on optimizing performance and reducing computational costs. For instance, GPT-4.1 offers improved coding capabilities, instruction-following, and a larger context window of up to 1 million tokens, surpassing GPT-4o’s 128,000-token limit. These advancements make newer models more suitable for modern development needs, but the transition requires careful planning.

Why Are These Models Being Deprecated?

The deprecation of o1, GPT-4.5, o3-mini, and GPT-4o reflects OpenAI’s commitment to streamlining its model portfolio. Older models often demand higher computational resources, which can strain infrastructure and increase costs. By retiring these models, OpenAI can allocate resources to newer, more efficient systems like GPT-4.1 and the o-series (o3 and o4-mini), which leverage advanced reasoning and multimodal capabilities. For example, o4-mini is optimized for low latency and high-quality output, making it ideal for real-time applications.

Additionally, developer feedback has shaped these changes. OpenAI noted that GPT-4.5, introduced as a research preview, provided valuable insights into large-scale model performance. However, its high compute requirements prompted the shift to GPT-4.1, which delivers comparable or better results at lower latency. This strategic pivot ensures that developers have access to cutting-edge tools without the overhead of maintaining legacy models.

Impact on Developers and Workflows

The deprecation announcement has elicited mixed reactions. On platforms like X, developers have voiced frustration, with some calling GPT-4.5 a “favorite” for its reliability and tone. Others, like AI observability platform co-founder Ben Hyak, described the move as “tragic,” highlighting their dependence on o3 and GPT-4.5 for daily tasks. These sentiments underscore the challenge of transitioning from familiar models to newer alternatives.

For developers using GitHub Copilot, the removal of these models from the model picker requires updating workflows and integrations. Copilot Enterprise administrators must enable access to alternative models, such as GPT-4.1, through policy settings in VS Code or github.com. OpenAI API users face similar adjustments, particularly those leveraging GPT-4.5 Preview for custom applications. Failure to migrate by the specified deadlines could result in error responses or disrupted services.

Transitioning to Newer Models

To ensure a smooth transition, developers should take proactive steps:

1. Assess Current Usage: Identify which deprecated models are integrated into your workflows. Check GitHub Copilot settings or OpenAI API configurations to confirm model dependencies.

2. Test Replacement Models: OpenAI recommends GPT-4.1  for GPT-4.5 and GPT-4o, o3 for o1, and o4-mini for o3-mini. Test these alternatives in your applications to evaluate performance, focusing on coding accuracy, latency, and context handling.

3. Update Integrations: Modify codebases and configurations to use the new models. For GitHub Copilot, select GPT-4.1 or o-series models in the model picker. For OpenAI API, update API calls to reference GPT-4.1 or other supported models.

4. Leverage Documentation: Consult OpenAI’s developer platform and GitHub’s Copilot documentation for migration guides and best practices.

5. Engage Support: GitHub Enterprise customers can contact account managers for assistance, while OpenAI API users can refer to the OpenAI Developer Community for support.

Opportunities with New Models

While deprecations may disrupt workflows, they also unlock opportunities. GPT-4.1 excels in frontend coding, instruction-following, and long-context tasks, making it a versatile choice for developers. The o3 model, with its enhanced reasoning, is ideal for complex problem-solving, scoring 88.9% on the 2025 AIME math competition. Meanwhile, o4-mini offers efficiency and multimodal support, enabling applications like real-time voice assistants or code debugging with minimal latency.

These models also introduce advanced features, such as function calling, structured outputs, and tool use, which empower developers to build agentic AI systems. For instance, o3 and o4-mini can autonomously execute Python code, browse the web, or generate images, streamlining multi-step tasks.

The deprecations signal OpenAI’s broader roadmap, with GPT-5 and full o4 models on the horizon. CEO Sam Altman has hinted at GPT-5’s unified architecture, integrating reasoning, multimodal capabilities, and AI agency. Expected by late 2025, GPT-5 could redefine AI interactions, building on lessons from GPT-4.5 and the o-series. In the interim, o3 and o4-mini, launched in April 2025, serve as stepping stones, offering developers a glimpse of OpenAI’s next-generation capabilities.

OpenAI’s deprecation of o1, GPT-4.5, o3-mini, and GPT-4o in 2025 reflects the company’s drive to innovate and optimize. While the transition poses challenges, it also presents opportunities to leverage more powerful models like GPT-4.1, o3, and o4-mini. By planning ahead, testing replacements, and exploring new features, developers can stay ahead of the curve. As AI continues to evolve, staying adaptable is key to harnessing its full potential.