OpenAI Optimizes GPT-5.5 and Retires GPT-4.5 and o3

OpenAI recently announced a series of changes regarding its ChatGPT service, including a significant update to the GPT-5.5 Instant model. This update aims to enhance the readability of AI-generated responses, making them more natural and better structured. The goal is to reduce the excessive use of long bullet-point lists, thereby providing a smoother user experience.

Alongside this improvement, OpenAI has decided to remove the Canvas feature from the GPT-5.5 Instant and GPT-5.5 Thinking models. Canvas, which appeared as a sidebar during text editing or code preview, will be replaced by specialized blocks directly integrated into the chat. This transition aims to simplify the writing and coding process for users.

Furthermore, OpenAI announced the retirement of two older models, o3 and GPT-4.5. The o3 model will be removed from ChatGPT on August 26, 2026, after a 90-day transition period, while GPT-4.5 will leave the platform on June 27, 2026, following a 30-day transition. During these periods, paying users will still be able to access these models through the model settings. Notably, the o3 model will remain available via the API for the time being, although GPT-4.5 has already been removed from that interface.