This release is a pretty radical departure. We stop respecting puppet's ordering for before', after, 'require, notify.
Now instead, all packages will be installed at the same time before the rest of the puppet run commences.
Another notable change is that all @system packages will always be updated, if you wish to lock one, you'll need to specify it.
This helps ensure the entire system is kept up to date even though your manifests may only specify the differences from the stage3.