Proguard

In case you are using Proguard you will need to define the following exception rules as shown here

# Bandyer now Kaleyra proprietary SDK
-keep class com.bandyer.** { *; }
-keep interface com.bandyer.** { *; }
-keep enum com.bandyer.** { *; }

-keep class com.kaleyra.** { *; }
-keep interface com.kaleyra.** { *; }
-keep enum com.kaleyra.** { *; }