diff --git a/common.ant.xml b/common.ant.xml
index 7f8244aea7..f46245f7de 100755
--- a/common.ant.xml
+++ b/common.ant.xml
@@ -54,7 +54,7 @@
   <property name="javac.debug" value="true"/>
   <property name="javac.debuglevel" value="lines,vars,source"/>
   <property name="javac.encoding" value="utf-8"/>
-  <property name="javac.release" value="8"/>
+  <property name="javac.release" value="11"/>
   <property name="javac.nowarn" value="true"/>
 
   <!-- javac and errorprone instructions from https://errorprone.info/docs/installation#ant -->
diff --git a/doc/build.xml b/doc/build.xml
index 3d0f89d353..1b777b094a 100644
--- a/doc/build.xml
+++ b/doc/build.xml
@@ -144,7 +144,7 @@
                  sourcepath="${gwt.root}/user/super/com/google/gwt/emul:${gwt.root}/dev/core/super/com/google/gwt/dev/jjs/intrinsic"
                  encoding="UTF-8"
                  access="public"
-                 source="${javac.release}"
+                 source="8"
                  packagenames="${JAVA_PKGS}"
                  docletpath="${project.build}/../build_tools/doctool/bin"
                  doclet="com.google.doctool.custom.JavaEmulSummaryDoclet">