OpenAI to retire GPT-4.5 and o3 models from ChatGPT

OpenAI is retiring the last of its GPT-4 generation models from its ChatGPT service, marking the end of an era for the artificial intelligence systems that helped ignite widespread public adoption of generative AI. The company confirmed it will phase out the GPT-4.5 model on June 27 and the o3 model on August 26.

The announcement was made in a product update posted to the OpenAI Help Center. The company stated the retirement of these older models, which have seen limited usage among paying subscribers, will allow it to better focus resources on serving its newer, most capable systems, specifically the GPT-5 series. Both models will remain available to paid ChatGPT users via the model settings until their respective sunset dates. Access to the models through OpenAI's application programming interface (API) is unaffected; the o3 model remains available there, while GPT-4.5 was previously removed from the API.

Alongside these retirements, OpenAI is rolling out an updated version of its current flagship model, GPT-5.5 Instant. The company says responses from this model will now feel more natural, be easier to read, and have better structure, with fewer lengthy bullet-point lists....