diff --git a/ipaacalib/java/build.properties b/ipaacalib/java/build.properties
index 12d9166e7e515e060a10d8ecfa8f8f3ab2aa8d40..be895bca6a60f3dace498ccc0d61db2abe088746 100644
--- a/ipaacalib/java/build.properties
+++ b/ipaacalib/java/build.properties
@@ -6,4 +6,5 @@ run.jvmargs= -Xms128m -Xmx512m  -Xss5M
 rebuild.list=
 publish.resolver=asap.sftp.publish
 dist.dir=../../dist
+javac.source=1.6
 javac.target=1.6