Hi @Phillip Allan-Harding,
Welcome to the Microsoft Q&A Platform! Thank you for asking your question here.
Yes, the latest version of Azure Functions Core Tools (v4) still supports the v3 programming model. You can still use the v3 programming model with Azure Functions Core Tools v4.x and Functions Runtime v4.x, ensuring that your existing function apps will function properly without any issues.
For further clarification, please refer to the following documentations: Document1, Document2
I hope this information helps you understand and resolve your issue. If you have any further concerns, please feel free to reach out.