diff --git a/build.gradle b/build.gradle
index d6cd9cb..652b5fe 100644
--- a/build.gradle
+++ b/build.gradle
@@ -52,6 +52,8 @@ def pkgLicenses = ['BSD 3-Clause']
 def pkgIssueTrackerUrl = mavenUrl + '/issues'
 def pkgLabels = ['java', 'annotation', 'processor', 'semantic', 'version']
 
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
 [compileJava, compileTestJava]*.options*.encoding = 'UTF-8'
 
 repositories {
diff --git a/kobalt/src/Build.kt b/kobalt/src/Build.kt
index f3440b4..db6abd2 100644
--- a/kobalt/src/Build.kt
+++ b/kobalt/src/Build.kt
@@ -1,6 +1,7 @@
 import com.beust.kobalt.buildScript
 import com.beust.kobalt.localMaven
 import com.beust.kobalt.plugin.java.javadoc
+import com.beust.kobalt.plugin.java.javaCompiler
 import com.beust.kobalt.plugin.packaging.assemble
 import com.beust.kobalt.plugin.packaging.install
 import com.beust.kobalt.plugin.publish.autoGitTag
@@ -80,6 +81,10 @@ val semver = project {
         compile("org.testng:testng:6.12")
     }
 
+    javaCompiler {
+        args("-source", "1.8", "-target", "1.8")
+    }
+
     assemble {
         jar {
             //fatJar = true