buildscript {
    ...
    dependencies {
-       classpath("com.android.tools.build:gradle:4.1.3")
+       classpath("com.android.tools.build:gradle:4.2.2")
    }
}

android {
    ...
    defaultConfig {
    ...
+       multiDexEnabled true
    }
    ...
    buildTypes {
        debug {
            ...
+           minifyEnabled true
+           shrinkResources  true
+           proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
        }
    }
}

# define which package or class not found on path DexPathList 
--keep class org.webrtc.** { *; }
+-keep class org.webrtc.** { *; }
+-keep class <your package>.** { *; }
# Example: java.lang.ClassNotFoundException: Didn't find class "com.example.MainActivity" on path: DexPathList
# you can use:
# -keep class com.example.** { *; }
# or
# -keep class com.example.MainActivity { *; }