Documentation of V1 & Push Notifications

ionic-v1
1

Hello, does anyone know if the current documentation in the three different sections of V1 about push notifications actually make up with the current packages. If not can anyone recommend some documentation that may have some more version specific implications?

I am using https://docs.ionic.io/setup.html, but apparently push notification packages referenced on this documentation are not the same version as what’s actually being installed:

I am receiving the following errors:

* What went wrong:
        A problem occurred configuring root project 'android'.
        > Could not resolve all dependencies for configuration ':_debugApkCopy'.
            > Could not find com.google.firebase:firebase-messaging:11.0.1.
              Required by:
                  project :
            > Could not find com.google.firebase:firebase-core:11.0.1.
              Required by:
                  project :

Is there a step I’m missing from the documentation by chance?