OpenAI updates ChatGPT model, phases out older o3 and GPT-4.5

OpenAI has announced an update to its GPT-5.5 Instant model for ChatGPT and its API, and will gradually phase out the older OpenAI o3 and GPT-4.5 models. The GPT-5.5 Instant, launched earlier, reduces hallucinations by 52.5% in high-risk areas like medicine, law, and finance, and boosts math, science, and visual reasoning. The updated model now delivers more natural, easier-to-read responses with clearer structure and fewer long lists. However, the Canvas feature is no longer available for GPT-5.5 Instant and GPT-5.5 Thinking; users can now use text and code blocks directly in chat replies. Paid users can still access Canvas during a transition period. OpenAI will remove the o3 model after a 90-day transition (by August 26, 2026) and GPT-4.5 after 30 days (by June 27, 2026) to focus on improving current models.