【Android Studio】Instant Run is disabled for non-debug variants

If you have manually set it in the manifest, then remove it and let the IDE automatically assign it. 
If you are using Gradle, make sure that your current variant is debuggable.

buildTypes {
    release {
        debuggable true  //發佈時 記得改為false
    }

【Android】Experimenting with Gradle dependencies

ref:
http://alexfu.github.io/android/2017/11/07/experimenting-with-gradle-dependencies.html