@Marvin In other words, I am deploying a prefect flow from a docker image that has prefect version 2.14.1 into a prefect server that has prefect version 3.0.2. Is this expected to work?

Running a Prefect flow from a Docker image with Prefect version 2.14.1 into a Prefect server with version 3.0.2 is not expected to work due to compatibility issues between major versions. From the findings on GitHub issues, Prefect 3.x and Prefect 2.x are not considered fully compatible. One of the issues indicates that compatibility across major versions is checked when entering a client context, and both the client and server must be on the same major version for compatibility (source: GitHub Pull Request 15252). Therefore, to ensure compatibility and prevent potential errors, it's recommended to align both the Docker image and the server to use the same major version of Prefect, preferably updating both to the latest stable release of Prefect 3.x if possible.