Altman described the first iteration of ChatGPT as a “research release.”
“Soon you will be able to have helpful assistants that talk to you, answer questions, and give advice. Later, you can have something that goes off and does tasks for you,” Altman wrote on X. “Eventually, you can have something that goes off and discovers new knowledge for you.”
At the time, ChatGPT relied on OpenAI’s GPT‑3.5 large language model. As the company built more advanced models — like GPT-4o in 2024 — ChatGPT became faster and more efficient in tackling a wider range of tasks.
The most recent version, GPT-5 replaced older versions — to the disappointment of some who missed the “personality” of GPT-4o. In response, Altman said users subscribed to ChatGPT Plus would still be able to use GPT-4o.
GPT-5 is the default model for non-subscribers, and OpenAI said it is designed for casual users.
“GPT‑5 not only outperforms previous models on benchmarks and answers questions more quickly, but—most importantly—is more useful for real-world queries,” the company said in August. “We’ve made significant advances in reducing hallucinations, improving instruction following, and minimizing sycophancy, while leveling up GPT-5’s performance in three of ChatGPT’s most common uses: writing, coding, and health.”
