diff --git a/app/build.gradle b/app/build.gradle
index a339499..f2cde5a 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -1,6 +1,5 @@
 apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
-apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion 26
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 0917461..a8826d0 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.2.1-bin.zip
diff --git a/lib/build.gradle b/lib/build.gradle
index 6eaf0bf..e992374 100644
--- a/lib/build.gradle
+++ b/lib/build.gradle
@@ -34,3 +34,27 @@ dependencies {
     androidTestImplementation 'com.android.support.test:runner:1.0.1'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
 }
+
+// build a jar with source files
+task sourcesJar(type: Jar) {
+    from android.sourceSets.main.java.srcDirs
+    classifier = 'sources'
+}
+
+task javadoc(type: Javadoc) {
+    failOnError  false
+    source = android.sourceSets.main.java.sourceFiles
+    classpath += project.files(android.getBootClasspath().join(File.pathSeparator))
+    classpath += configurations.compile
+}
+
+// build a jar with javadoc
+task javadocJar(type: Jar, dependsOn: javadoc) {
+    classifier = 'javadoc'
+    from javadoc.destinationDir
+}
+
+artifacts {
+    archives sourcesJar
+    archives javadocJar
+}
\ No newline at end of file
diff --git a/settings.gradle b/settings.gradle
index 3cbe249..8c2a2e0 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -1 +1 @@
-include ':app', ':lib'
+include ':lib'