diff --git a/build.gradle b/build.gradle
index 61f286a..dcc08d2 100644
--- a/build.gradle
+++ b/build.gradle
@@ -7,7 +7,7 @@
 
 group = 'org.ntlab'
 version = '0.0.1-SNAPSHOT'
-sourceCompatibility = '11'
+sourceCompatibility = '1.8'
 
 repositories {
     mavenCentral()