When a package is added which alters the versions of already loaded packages, Julia needs to be restarted to access the correct versions. The feedback to the user is however somewhat timid, and as a new user I failed to take action, when seeing for example:
6 dependencies precompiled but different versions are currently loaded. Restart julia to access the new versions
Howabout prefacing the text with
Warning:, adding some exclamation marks, and changing the colour to red?