DSL element 'DexOptions.incremental' is obsolete and will be removed at the end of 2018.

DSL element 'DexOptions.incremental' is obsolete and will be removed at the end of 2018.

http://google.github.io/android-gradle-dsl/current/com.android.build.gradle.internal.dsl.DexOptions.html#com.android.build.gradle.internal.dsl.DexOptions

dexOptions {
    javaMaxHeapSize "4g"
    jumboMode = true
    incremental false
}

https://stackoverflow.com/questions/32890868/whats-the-meaing-of-incremental-predexlibraries-jumbomode-inside-dexoptions

결론 

incremental 제거