People upgrading from 1.x installations that have $JENKINS_HOME/config.xml does not currently get the setup wizard dialog, which means they will not get any of the new functionalities that fresh installations is getting, most notably pipeline. This is unacceptable.

Make sure upgrading users are steered into accepting the recommended set of plugins and enable security, while still providing an option to opt out of it for the few people who know what they are doing.