diff --git a/build.gradle b/build.gradle
index 4a3549575f489cf610567d629d02c502422f66a4..c3cc8f8efd79c9b297b2e3144860f86904a9f0a1 100644
--- a/build.gradle
+++ b/build.gradle
@@ -5,6 +5,7 @@ apply plugin: 'maven'
 
 project.version = '3.2.8'
 project.group = 'de.stups'
+sourceCompatibility = 1.5
 
 repositories {
     maven {