A new version of the technology that powers an AI chatbot that captivated the tech industry four months ago has improved on its predecessor. It is an expert on an array of subjects, even wowing doctors with its medical advice. It can describe images, and it’s close to telling jokes that are almost funny.

But the long-rumored new artificial intelligence system, GPT-4, still has a few of the quirks and makes some of the same habitual mistakes that baffled researchers when that chatbot, ChatGPT, was introduced.

And although it’s an awfully good test taker, the system — from San Francisco startup OpenAI — is not on the verge of matching human intelligence. Here is a brief guide to GPT-4: