Error:Execution failed for task ‘:app:preDebugAndroidTestBuild’. > Conflict with dependency ‘com.android.support:support-annotations’ in project ‘:app’. Resolved versions for app (26.1.0) and test app (27.1.1) differ. See https://d.android.com/r/tools/test-apk-dependency-conflicts.html for details.

Solution : compile ‘com.android.support:support-annotations:27.1.1’ to gradle(app) and sync . Solved 🙂 Example : apply plugin: ‘com.android.application’ android { compileSdkVersion 26 defaultConfig { applicationId “com.arifhasnat.islamicbooks” minSdkVersion…