diff --git a/apps/addressbook/build.xml b/apps/addressbook/build.xml
index e4e913cb2..eed69a3fa 100644
--- a/apps/addressbook/build.xml
+++ b/apps/addressbook/build.xml
@@ -86,6 +86,8 @@
 		                <attribute name="Build-Date" value="${build.timestamp}" />
 		                <attribute name="Base-Revision" value="${workspace.version}" />
 		                <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+				<attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+				<attribute name="X-Compile-Target-JDK" value="${javac.version}" />
 			</manifest>
 		</jar>
 	</target>
@@ -106,6 +108,8 @@
 		                <attribute name="Build-Date" value="${build.timestamp}" />
 		                <attribute name="Base-Revision" value="${workspace.version}" />
 		                <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+				<attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+				<attribute name="X-Compile-Target-JDK" value="${javac.version}" />
 			</manifest>
 		</war>
 		<delete dir="${dist}/tmp"/>
diff --git a/apps/desktopgui/build.xml b/apps/desktopgui/build.xml
index b31cc86df..a42633518 100644
--- a/apps/desktopgui/build.xml
+++ b/apps/desktopgui/build.xml
@@ -83,6 +83,8 @@
 				<attribute name="Build-Date" value="${build.timestamp}" />
 				<attribute name="Base-Revision" value="${workspace.version}" />
 				<attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+				<attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+				<attribute name="X-Compile-Target-JDK" value="${javac.version}" />
 			</manifest>
 		</jar>
 	</target>
diff --git a/apps/i2psnark/java/build.xml b/apps/i2psnark/java/build.xml
index ee3ad0f03..3ecde0393 100644
--- a/apps/i2psnark/java/build.xml
+++ b/apps/i2psnark/java/build.xml
@@ -84,6 +84,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>    
@@ -130,6 +132,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </war>
     </target>
diff --git a/apps/i2ptunnel/java/build.xml b/apps/i2ptunnel/java/build.xml
index 6c4698a27..93f5cc339 100644
--- a/apps/i2ptunnel/java/build.xml
+++ b/apps/i2ptunnel/java/build.xml
@@ -72,6 +72,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.j.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
         <jar destfile="./build/temp-beans.jar" basedir="./build/obj" includes="**/ui/*.class **/EditBean.class **/IndexBean.class" />
@@ -103,6 +105,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.j.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
@@ -241,6 +245,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.w.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </war>
     </target>
diff --git a/apps/imagegen/identicon/build.xml b/apps/imagegen/identicon/build.xml
index e0e85bd53..831b3ff7f 100644
--- a/apps/imagegen/identicon/build.xml
+++ b/apps/imagegen/identicon/build.xml
@@ -71,6 +71,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/apps/imagegen/imagegen/build.xml b/apps/imagegen/imagegen/build.xml
index 7cc657c05..bc0d96f24 100644
--- a/apps/imagegen/imagegen/build.xml
+++ b/apps/imagegen/imagegen/build.xml
@@ -75,6 +75,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </war>
     </target>
diff --git a/apps/imagegen/zxing/build.xml b/apps/imagegen/zxing/build.xml
index c878015b1..c615d8683 100644
--- a/apps/imagegen/zxing/build.xml
+++ b/apps/imagegen/zxing/build.xml
@@ -17,6 +17,7 @@
     </target>
 
     <!-- only used if not set by a higher build.xml -->
+    <property name="javac.version" value="1.7" />
     <property name="javac.compilerargs7" value="" />
 
     <target name="compile" depends="depend">
@@ -39,7 +40,7 @@
 	<mkdir dir="./buildTest/obj" />
         <javac
             srcdir="./test/junit"
-            debug="true" deprecation="on" source="1.7" target="1.7"
+            debug="true" deprecation="on" source="${javac.version}" target="${javac.version}"
             includeAntRuntime="false"
             destdir="./buildTest/obj"
             classpath="./build/zxing.jar" >
@@ -75,6 +76,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/apps/jetty/build.xml b/apps/jetty/build.xml
index 1f5c81028..f0b2c7cce 100644
--- a/apps/jetty/build.xml
+++ b/apps/jetty/build.xml
@@ -340,6 +340,8 @@
                 <!-- needed by JettyStart for pre-0.7.5 wrapper.config -->
                 <attribute name="Class-Path" value="jetty-deploy.jar jetty-xml.jar" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>    
diff --git a/apps/ministreaming/java/build.xml b/apps/ministreaming/java/build.xml
index 8232492b1..cbef281b9 100644
--- a/apps/ministreaming/java/build.xml
+++ b/apps/ministreaming/java/build.xml
@@ -86,6 +86,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/apps/routerconsole/java/build.xml b/apps/routerconsole/java/build.xml
index 76162ae04..522ee06a7 100644
--- a/apps/routerconsole/java/build.xml
+++ b/apps/routerconsole/java/build.xml
@@ -130,6 +130,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.j.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
@@ -302,6 +304,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.w.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </war>
     </target>
diff --git a/apps/sam/java/build.xml b/apps/sam/java/build.xml
index 9aab0527c..5891bd1a8 100644
--- a/apps/sam/java/build.xml
+++ b/apps/sam/java/build.xml
@@ -77,6 +77,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/apps/streaming/java/build.xml b/apps/streaming/java/build.xml
index 0c2b80d71..1b421e2f5 100644
--- a/apps/streaming/java/build.xml
+++ b/apps/streaming/java/build.xml
@@ -213,6 +213,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/apps/susidns/src/build.xml b/apps/susidns/src/build.xml
index eefdacd59..ac9a6f63a 100644
--- a/apps/susidns/src/build.xml
+++ b/apps/susidns/src/build.xml
@@ -117,6 +117,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </war>
     </target>
diff --git a/apps/susimail/build.xml b/apps/susimail/build.xml
index b3ede69b3..1df5e1129 100644
--- a/apps/susimail/build.xml
+++ b/apps/susimail/build.xml
@@ -81,6 +81,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </war>
     </target>
diff --git a/apps/systray/java/build.xml b/apps/systray/java/build.xml
index 448c5ca8f..8d00ba1f8 100644
--- a/apps/systray/java/build.xml
+++ b/apps/systray/java/build.xml
@@ -65,6 +65,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/core/java/build.xml b/core/java/build.xml
index 3143f550c..1f301ae59 100644
--- a/core/java/build.xml
+++ b/core/java/build.xml
@@ -108,6 +108,8 @@
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Main-Class" value="net.i2p.util.CommandLine" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/installer/java/build.xml b/installer/java/build.xml
index f0caf6b86..e73ff9036 100644
--- a/installer/java/build.xml
+++ b/installer/java/build.xml
@@ -57,6 +57,8 @@
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.util.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/installer/tools/java/build.xml b/installer/tools/java/build.xml
index c7dff1b4e..40d8514a7 100644
--- a/installer/tools/java/build.xml
+++ b/installer/tools/java/build.xml
@@ -38,6 +38,8 @@
                 <attribute name="Built-By" value="${build.built-by}" />
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/router/java/build.xml b/router/java/build.xml
index 79c3d5d53..7097d8a77 100644
--- a/router/java/build.xml
+++ b/router/java/build.xml
@@ -78,6 +78,8 @@
                 <attribute name="Base-Revision" value="${workspace.version}" />
                 <attribute name="Main-Class" value="net.i2p.router.CommandLine" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
+                <attribute name="X-Compile-Source-JDK" value="${javac.version}" />
+                <attribute name="X-Compile-Target-JDK" value="${javac.version}" />
             </manifest>
         </jar>
     </target>