Multiple entries with same key: FirebaseInstanceId

Question

Getting strange error after updating Android Studio to 3.5.

The error comes only for release apk. debug apk generates well.

Multiple entries with same key: Method com.google.firebase.iid.FirebaseInstanceId.zza Proto LLL com.google.android.gms.tasks.Task java.lang.String java.lang.String=Encoded method Method com.google.firebase.iid.FirebaseInstanceId.zza Proto LLL com.google.android.gms.tasks.Task java.lang.String java.lang.String and Method com.google.firebase.iid.FirebaseInstanceId.zza Proto LLL com.google.android.gms.tasks.Task java.lang.String java.lang.String=Encoded method Method com.google.firebase.iid.FirebaseInstanceId.zza Proto LLL com.google.android.gms.tasks.Task java.lang.String java.lang.String

Answer 1

Add this line to proguard files :

-keep class com.google.firebase.iid.FirebaseInstanceId { zza(...); }

see details here.