API 'variant.getExternalNativeBuildTasks()' is obsolete

This has been fixed in the latest release of the Fabric gradle plugin, 1.28.0. Have this in your top-level build.gradle:

buildscript {
  // ... repositories, etc. ...

   dependencies {
       // ...other dependencies ...
       classpath 'io.fabric.tools:gradle:1.28.0'
   }
}

You can add

android.debug.obsoleteApi=true

to the gradle.properties file and it will show you stack trace, so you can determine what module is using obsolete APIs

However, this is considered as a warning at the moment, not an error. It's just annoying to see everytime you sync gradle . In the future modules will be updated & this warning will be gone

Hope this helps :)

Probably now is late, but it helped me:

  apply plugin: 'com.android.application'
  apply plugin: 'io.fabric'
  apply plugin: 'kotlin-android'
  apply plugin: 'kotlin-android-extensions'

The problem was with apply plugin: 'io.fabric' I just had to comment this line and after it worked

apply plugin: 'com.android.application'
//apply plugin: 'io.fabric'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

It happens after I updated Android Studio to 3.3.0.

Or you can downgrade to Android Studio 3.2.1.