Request: update dependencies and replace deprecated usages

compileSdkVersion 25 - should be 29
buildToolsVersion '25.0.3' - should be removed
targetSdkVersion 25 - should be 29

implementation 'com.android.support:appcompat-v7:25.3.1'
implementation 'com.android.support:design:25.3.1'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
implementation 'com.android.support:support-v4:25.3.1'
-should use android x

implementation 'com.android.support:design:25.3.1'
implementation 'com.google.android.gms:play-services-base:11.0.1'
implementation 'com.google.android.gms:play-services-identity:11.0.1'
implementation 'com.google.android.gms:play-services-auth:11.0.1'
implementation 'com.google.android.gms:play-services-auth-api-phone:11.0.1'
-all of these are very outdated and the samples use deprecated classes and functions.

Start by locating the Android build files containing the listed compileSdkVersion, targetSdkVersion, buildToolsVersion, support libraries, and Google Play Services dependencies. Review the affected sample usages for deprecated classes and functions; done means the SDK and dependencies are updated, support libraries are migrated to AndroidX, and deprecated usages are replaced.

Written by the indexing model from the issue text.