diff --git a/build.gradle b/build.gradle
index 17911739faad43cb115e18b1b1636ada932fc49c..7a4c891eb648035e4000e77947c7747fd0993edf 100644
--- a/build.gradle
+++ b/build.gradle
@@ -5,6 +5,7 @@ apply plugin: 'maven'
 
 project.version = '3.2.9-SNAPSHOT'
 project.group = 'de.stups'
+sourceCompatibility = 1.5
 
 repositories {
     maven {