diff --git a/build.xml b/build.xml
index 5261d7222..86a11510e 100644
--- a/build.xml
+++ b/build.xml
@@ -26,7 +26,7 @@
              classpathref="classpath"/>
     <!-- make sure the record class files are all compiled -->
     <javac srcdir="src/java" destdir="${classes.dir}" debug="on" optimize="${build.optimize}"
-           deprecation="on" source="1.5" target="1.5">
+           deprecation="on" source="1.6" target="1.5">
       <classpath refid="classpath"/>
       <include name="**/*Record.java"/>
     </javac>
@@ -42,7 +42,7 @@
              classname="com.threerings.presents.tools.GenDObjectTask"/>
     <!-- make sure the dobject class files are all compiled -->
     <javac srcdir="src/java" destdir="${classes.dir}" includeAntRuntime="false" debug="on"
-           optimize="${build.optimize}" deprecation="on" source="1.5" target="1.5">
+           optimize="${build.optimize}" deprecation="on" source="1.6" target="1.5">
       <classpath refid="classpath"/>
       <include name="**/*Object.java"/>
     </javac>
@@ -58,7 +58,7 @@
              classname="com.threerings.presents.tools.GenServiceTask"/>
     <!-- make sure the service class files are all compiled -->
     <javac srcdir="src/java" destdir="${classes.dir}" includeAntRuntime="false" debug="on"
-           optimize="${build.optimize}" deprecation="on" source="1.5" target="1.5">
+           optimize="${build.optimize}" deprecation="on" source="1.6" target="1.5">
       <classpath refid="classpath"/>
       <include name="**/*Service.java"/>
       <exclude name="**/InvocationService.java"/>
@@ -87,7 +87,7 @@
              classname="com.threerings.presents.tools.GenReceiverTask"/>
     <!-- make sure the receiver class files are all compiled -->
     <javac srcdir="src/java" destdir="${classes.dir}" includeAntRuntime="false"
-           debug="on" optimize="${build.optimize}" deprecation="on" source="1.5" target="1.5">
+           debug="on" optimize="${build.optimize}" deprecation="on" source="1.6" target="1.5">
       <classpath refid="classpath"/>
       <include name="**/*Receiver.java"/>
       <exclude name="**/InvocationReceiver.java"/>
@@ -158,7 +158,7 @@
   <!-- build the java class files -->
   <target name="compile" depends="prepare">
     <javac srcdir="src/java" destdir="${classes.dir}" includeAntRuntime="false"
-           debug="on" optimize="{$build.optimize}" deprecation="on" source="1.5" target="1.5">
+           debug="on" optimize="{$build.optimize}" deprecation="on" source="1.6" target="1.5">
       <classpath refid="classpath"/>
       <compilerarg value="-Xlint"/>
       <compilerarg value="-Xlint:-serial"/>