Android Build Execution Failed Due To Incompatible Library Versions

Implementing Google sign in using firebase. This is my project level build.gradle buildscript { repositories { google() jcenter() } dependencies {

Solution 1:

dependencies {
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
implementation 'com.android.support:design:26.1.0'
compile 'com.google.code.gson:gson:2.8.2'
compile 'com.squareup.retrofit:retrofit:1.9.0'
compile 'com.squareup.okhttp:okhttp:2.4.0'
compile 'com.squareup.okio:okio:1.5.0'
compile 'com.squareup.okhttp:okhttp-urlconnection:2.4.0'
compile 'com.google.firebase:firebase-auth:11.8.0'
compile 'com.google.android.gms:play-services-auth:11.8.0'
}
apply plugin: 'com.google.gms.google-services'

Use this file , remember to add google-services configuration file .