diff --git a/build.gradle b/build.gradle
index 6eee127f..8cf4392c 100644
--- a/build.gradle
+++ b/build.gradle
@@ -21,6 +21,9 @@ apply plugin: 'signing'
 apply plugin: 'com.jfrog.bintray'
 apply plugin: 'maven-publish'
 
+sourceCompatibility = 1.7
+targetCompatibility = 1.7
+
 group = 'com.ullink.slack'
 archivesBaseName = 'simpleslackapi'
 version = '0.4.3'