@Marvin If I have a flow that is running on Python 3.8 and I’d like to run it on my local Prefect Server, does the Server’s version must be Prefect 2.0?

Running a Prefect flow locally on your Prefect Server does not require the server to be on version 2.0. Prefect 3.x is compatible with Python 3.9 or newer, so you should ensure your environment is up to date with these requirements. When managing a Prefect server, it's important to maintain compatibility between the server and client versions. Prefect aims to maintain backward compatibility, but newer clients may not work with older servers. Therefore, it's recommended that all clients are the same version as the server or older. For more details, you can refer to the Prefect documentation.

@Marvin As said, my flow is running on Python 3.8. You’re saying that Prefect 3.x supports Python 3.9 or newer, which means Python 3.8 is not supported. Does this mean that my Prefect Server version must be 2.x?

Yes, if your flow is running on Python 3.8, you would need to use Prefect 2.x, as Prefect 3.x requires Python 3.9 or newer. Therefore, your Prefect Server should also be on version 2.x to maintain compatibility with your current Python version.

@Marvin Will a Prefect Server of version 2.x will also be able to run flows that use Prefect 3.x?

A Prefect Server of version 2.x is not compatible with flows that use Prefect 3.x. Prefect 3.x introduces significant changes and enhancements that require the corresponding server version. If you want to run flows written with Prefect 3.x, you'll need to upgrade your server to the 3.x version as well. For more detailed guidance on migrating or compatibility, you might find the Prefect migration guide helpful.