1. Add next lines to the file `proguard-rules.pro`

```
-optimizations code/removal/*
-assumenosideeffects class android.util.Log {
    public static boolean isLoggable(java.lang.String, int);
    public static int v(...);
    public static int d(...);
    public static int i(...);
    public static int w(...);
}
-assumenosideeffects class java.lang.Exception {
    public void printStackTrace();
}

-assumenosideeffects class timber.log.Timber* {
    public static *** v(...);
}
-assumenosideeffects class * implements org.slf4j.Logger {
    public void trace(...);
}
```

2. Change in build.gradle file with ending `-optimize`
```
proguardFiles getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro"
```