4.1. Notebook server life cycle

Red Hat will periodically update supported software versions for notebook server images and Python packages automatically installed with each image. When we update the supported versions, we need to ensure they don't break any existing user notebooks. Users would be frustrated if they restart their server and the version updates caused something to break in an existing notebook.

Requirements:

https://docs.google.com/document/d/1zExbPL9gUnCL4i1nFIwQBLE7is9NY812lU3vNKB8bDA/edit?usp=sharing 

1. The system must not break (i.e. cause code to start generating errors when run) any existing notebooks with updates to software versions without explicitly getting the user's consent to update supported software versions. The intent is that if users opt into the updates, they understand that the updates could potentially cause issues in their existing notebooks.

The planned model is to support n (latest - recommended) and n-1 versions of notebook images. When we release a new notebook image version, it will be the recommended version. To help mitigate concerns about breaking existing notebooks, we will also support the previous version (n-1). We expect to release new notebook images ~ 1/quarter, so that will give users some time to adopt the new notebook image before the previous one is deprecated. As a future roadmap item, we also plan to support custom notebook images, which will allow customers to "freeze" specific versions in a custom-defined notebook image.