diff --git a/java/proguard-annotations/build.gradle b/java/proguard-annotations/build.gradle
index 35878019..3ca9dae5 100644
--- a/java/proguard-annotations/build.gradle
+++ b/java/proguard-annotations/build.gradle
@@ -6,4 +6,8 @@
  */
 
 apply plugin: 'java'
+
+sourceCompatibility = '1.7'
+targetCompatibility = '1.7'
+
 apply from: rootProject.file('gradle/release.gradle')