AndroidX

AndroidX replaces the original support library APIs with packages in the androidx namespace.
Only the package and Maven artifact names changed; class, method, and field names did not change.

~ Migrating to AndroidX | Android Developers

https://developer.android.com/jetpack/androidx/migrate

~ Class Mappings | Android Developers

https://developer.android.com/jetpack/androidx/migrate/class-mappings

~ Migrating to AndroidX: The time is right (Android Dev Summit '19)

https://www.youtube.com/watch?v=Hyt7LR5mXLc