diff --git a/kotlinlog/build.gradle b/kotlinlog/build.gradle
index fc40b29..ea2987f 100644
--- a/kotlinlog/build.gradle
+++ b/kotlinlog/build.gradle
@@ -15,9 +15,9 @@ android {
     defaultConfig {
         minSdkVersion 16
         targetSdkVersion 27
-        versionCode 2
-        versionName "2.0"
-
+        versionCode 3
+        versionName "2.2.2"
+        consumerProguardFile('proguard-rules.pro')
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
     buildTypes {
diff --git a/kotlinlog/proguard-rules.pro b/kotlinlog/proguard-rules.pro
index 30d549f..42657a8 100644
--- a/kotlinlog/proguard-rules.pro
+++ b/kotlinlog/proguard-rules.pro
@@ -31,4 +31,6 @@
 # Most of volatile fields are updated with AFU and should not be mangled
 -keepclassmembernames class kotlinx.** {
     volatile <fields>;
-}
\ No newline at end of file
+}
+
+-keep class quanti.com.kotlinlog.Log
\ No newline at end of file
diff --git a/kotlinlog/src/main/kotlin/quanti/com/kotlinlog/LogInternal.kt b/kotlinlog/src/main/kotlin/quanti/com/kotlinlog/LogInternal.kt
index 22ad967..0009b79 100644
--- a/kotlinlog/src/main/kotlin/quanti/com/kotlinlog/LogInternal.kt
+++ b/kotlinlog/src/main/kotlin/quanti/com/kotlinlog/LogInternal.kt
@@ -3,7 +3,7 @@ package quanti.com.kotlinlog
 import quanti.com.kotlinlog.base.ILogger
 import quanti.com.kotlinlog.file.FileLogger
 import quanti.com.kotlinlog.utils.getClassNameWithoutPackage
-import java.io.File
+import java.lang.IllegalStateException
 
 /***
  * PRIVATE
@@ -78,5 +78,5 @@ private fun getMethodStackTraceElement(): StackTraceElement {
         }
     }
 
-    return null!!
+    throw IllegalStateException("class log.Log is missing")
 }
\ No newline at end of file