diff --git a/java/google/registry/env/production/backend/WEB-INF/appengine-web.xml b/java/google/registry/env/production/backend/WEB-INF/appengine-web.xml
index 3dbbbc1c2..c5a10f8fa 100644
--- a/java/google/registry/env/production/backend/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/production/backend/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>backend</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/production/default/WEB-INF/appengine-web.xml b/java/google/registry/env/production/default/WEB-INF/appengine-web.xml
index 0b2da7b6b..8afde29d1 100644
--- a/java/google/registry/env/production/default/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/production/default/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>default</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/production/tools/WEB-INF/appengine-web.xml b/java/google/registry/env/production/tools/WEB-INF/appengine-web.xml
index 11b6162eb..0ad010c06 100644
--- a/java/google/registry/env/production/tools/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/production/tools/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>tools</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>