When ChatGPT first gained popularity in 2022, GPT-3.5 was the default model. In March 2023, the more advanced GPT-4 replaced it. Since then, both models have been lapped by a much more capable GPT-4o, which will soon replace GPT-4.

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On Thursday, OpenAI updated its ChatGPT release notes to announce that GPT-4 was being retired from ChatGPT and fully replaced by GPT-4o starting April 30. In the changelog, OpenAI said that GPT-4o consistently outperformed its predecessor in writing, coding, and STEM in head-to-head evaluations. 

Retiring this model won't be much of a loss, as GPT-4o's release in May 2024 was a major upgrade. The "o" in GPT-4o stands for Omni and refers to the model's multimodal features. These features allow it to understand text, audio, image, and video inputs and output text, audio, and images, greatly expanding upon what GPT-4 could do. 

Since then, GPT-4o has continued to be upgraded to expand its assistance further. The changelog shows a March 27 upgrade that improved GPT-4o's capabilities across different areas, including smarter problem-solving in STEM and coding and enhanced instruction-following and formatting accuracy. OpenAI said these upgrades have made it a "natural successor" to GPT-4. 

Also: OpenAI is pushing for industry-specific AI benchmarks - why that matters

Currently, subscribers can access GPT-4 under the model toggle, but they will be met with a caution symbol alerting them that the model is leaving on April 30. Developers and researchers will still be able to access GPT-4 in the API even past the retirement date, where they can also access other legacy models such as GPT-3.5, DALL-E 2, and more. 

This update won't impact free users as the default model for that model is GPT-4o mini, and the only other models they have limited access to include GPT-4o and o3-mini. The news comes at the same time as ChatGPT's latest feature update, which expanded the chatbot's memory feature to reference all of your past conversations and create a more personalized experience. 

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