Google has replaced the Android support library with Android Jetpack (AndroidX). “Unfortunately”, they also changed packages and names of Maven artifacts. All new development will occur in the AndroidX library, so if we want to use the new features (and probably even bug fixes) we need to migrate to AndroidX.

Official migration guide – https://developer.android.com/jetpack/androidx/migrate

Some tips on migration
https://blog.danlew.net/2018/11/14/the-reality-of-migrating-to-androidx/
https://medium.com/androiddevelopers/cross-stitching-plaid-and-androidx-7603a192348e