Q:

Build fails when AppsFlyer is used with ProGuard

I'm following this manual to integrate AppsFlyer into our Android app. 
When I try to build the project with minifyEnabled true the following warnings appear in the build log:

Warning: com.appsflyer. GcmInstanceIdListener: can't find superclass or interface com.google.android.gms.iid. InstanceIDListenerService
Warning: com.appsflyer. GcmInstanceIdListener: can't find referenced class com.google.android.gms.iid. InstanceID
Warning: com.appsflyer. GcmInstanceIdListener: can't find referenced class com.google.android.gms.iid. InstanceIDListenerService
  Warning: com.appsflyer. GcmInstanceIdListener: can't find referenced class com.google.android.gms.iid. InstanceID
  Warning: com.appsflyer. GcmInstanceIdListener: can't find referenced class com.google.android.gms.iid. InstanceID
Warning: com.appsflyer. GcmInstanceIdListener: can't find referenced class com.google.android.gms.iid. InstanceIDListenerService
Warning: com.appsflyer. GcmInstanceIdListener: can't find referenced class com.google.android.gms.iid. InstanceIDListenerService
Warning: com.appsflyer.u: can't find referenced class com.google.android.gms.iid. InstanceIDListenerService

And the build fails. 
Here is relevant part of the app's module build.gradle:
dependencies {
    implementation 'com.google.firebase:firebase-core:16.0.7'
    implementation 'com.google.firebase:firebase-messaging:17.3.4'
    implementation 'com.appsflyer:af-android-sdk:4+@aar'
    implementation 'com.android.installreferrer:installreferrer:1.0'
}

Here is relevant part of ProGuard configuration:
-dontwarn com.android.installreferrer

A:

Please add the following as well:
-dontwarn com.appsflyer.** 

https://support.appsflyer.com/hc/en-us/articles/207032126-AppsFlyer-SDK-Integration-Android#11-known-issues

