diff --git a/app/build.gradle b/app/build.gradle
index f8e0488..f94139f 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -3,7 +3,7 @@ apply plugin: 'witness'
 
 android {
     compileSdkVersion 21
-    buildToolsVersion '19.1.0'
+    buildToolsVersion '21.0.0'
     defaultConfig {
         minSdkVersion 9
         targetSdkVersion 21