diff --git a/WEB-INF/appengine-web.xml b/WEB-INF/appengine-web.xml
index 58c62aa..ae8876a 100644
--- a/WEB-INF/appengine-web.xml
+++ b/WEB-INF/appengine-web.xml
@@ -3,6 +3,8 @@
   <application>public-firing-range</application>
   <version>1</version>
 
+  <runtime>java8</runtime>
+
   <system-properties>
     <property name="java.util.logging.config.file" value="WEB-INF/logging.properties"/>
   </system-properties>