As of my last update in early 2024, OpenAI's latest flagship model is **GPT-4**.

It's the successor to GPT-3.5 and represents a significant leap in capabilities, including:

*   **Vastly improved reasoning abilities:** GPT-4 is much better at understanding context, handling complex instructions, and providing more accurate and nuanced answers.
*   **Multimodality (in some versions):** While not all versions are multimodal, GPT-4 has demonstrated the ability to understand and process image inputs, leading to capabilities like describing images, answering questions about them, and even generating code from visual representations.
*   **Longer context windows:** This allows the model to process and remember more information within a single conversation or prompt.
*   **Reduced factual errors and hallucinations:** While still not perfect, GPT-4 is designed to be more reliable and less prone to generating incorrect information.

It's important to note that OpenAI often releases iterative updates and specialized versions of their models. However, GPT-4 is currently considered their most advanced and capable general-purpose flagship model.
