diff --git a/apps/addressbook/build.xml b/apps/addressbook/build.xml
index e4e913cb20e6e43b58d744d24ad619d9cfaa91bc..eed69a3fa427bcef4fe73bd1d78ec65253a6b315 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="${dist}/tmp"/>
diff --git a/apps/desktopgui/build.xml b/apps/desktopgui/build.xml
index b31cc86dfdbd29405a65c2a6afb24bcf9005224c..a42633518952ee435744c88e7fd31b406abc696e 100644
--- a/apps/desktopgui/build.xml
+++ b/apps/desktopgui/build.xml
@@ -83,6 +83,8 @@
 				<attribute name="Build-Date" value="${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 ee3ad0f036712bdb12cd40910d246bf45cb01e22..3ecde039383a1d13a66fa19cbbd0c083ee5fbb9d 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 6c4698a27a61f81d5b1396620eb89c816271954a..93f5cc3391f6130fa152bc8bc77e837935d91328 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="${javac.version}" />
             </manifest>
         </war>
     </target>
diff --git a/apps/imagegen/identicon/build.xml b/apps/imagegen/identicon/build.xml
index e0e85bd53287ac6658dd4f8998d4622a9907f031..831b3ff7f33236f33a7c2e826d8efb53f35a819b 100644
--- a/apps/imagegen/identicon/build.xml
+++ b/apps/imagegen/identicon/build.xml
@@ -71,6 +71,8 @@
                 <attribute name="Build-Date" value="${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 7cc657c05177f0613d2363cd530ae247b18d1011..bc0d96f24fbb3247c74c39c3025904c646d034c3 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 c878015b17eafa31bacfd5441dc7aac3f16b4281..c615d86839e04f231bb76cdef0cc2dc6c65c6a80 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="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/apps/jetty/build.xml b/apps/jetty/build.xml
index 1f5c8102844fcfd148e5e531767c949477358f5d..f0b2c7cce669d63b66a528e62d1bd680f7d5fcdc 100644
--- a/apps/jetty/build.xml
+++ b/apps/jetty/build.xml
@@ -340,6 +340,8 @@
                 <!-- needed by JettyStart for pre-0.7.5 wrapper.config -->
                 <attribute name="Class-Path" value="jetty-deploy.jar jetty-xml.jar" />
                 <attribute name="Workspace-Changes" value="${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 8232492b1f7ceaa2af6e7fbb430965d9f0ed4073..cbef281b9375b9ef35420fe91fd1ec03b231779b 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="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/apps/routerconsole/java/build.xml b/apps/routerconsole/java/build.xml
index 76162ae04cb781b9aae68ae7570cb2c45009ba13..522ee06a76f67e8f09eaefda393af1f4c5489b75 100644
--- a/apps/routerconsole/java/build.xml
+++ b/apps/routerconsole/java/build.xml
@@ -130,6 +130,8 @@
                 <attribute name="Build-Date" value="${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="${javac.version}" />
             </manifest>
         </war>
     </target>
diff --git a/apps/sam/java/build.xml b/apps/sam/java/build.xml
index 9aab0527c6d07fdb4a400b525ac0751dc28a0862..5891bd1a84c57ebaf816cacc7f694c4b25edd2bf 100644
--- a/apps/sam/java/build.xml
+++ b/apps/sam/java/build.xml
@@ -77,6 +77,8 @@
                 <attribute name="Build-Date" value="${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 0c2b80d71e5e85e6d187d9ec0fde360b82945ca4..1b421e2f52e94c618633c4aea385423f370fa0c9 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="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/apps/susidns/src/build.xml b/apps/susidns/src/build.xml
index eefdacd5950b6c89d145b038ed541c6f011f17d1..ac9a6f63aa3e0e43ecefdfa783d2406fcf82c3c1 100644
--- a/apps/susidns/src/build.xml
+++ b/apps/susidns/src/build.xml
@@ -117,6 +117,8 @@
                 <attribute name="Build-Date" value="${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 b3ede69b37f2c70aaaac3a2975a8666f1683576f..1df5e1129bde691ce68eee4f87629b166839cac4 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="${javac.version}" />
             </manifest>
         </war>
     </target>
diff --git a/apps/systray/java/build.xml b/apps/systray/java/build.xml
index 448c5ca8fcafa0bff60a7aa5972f6d2284f61f2b..8d00ba1f8b6edac68f8b9f7b124ae246086baaa7 100644
--- a/apps/systray/java/build.xml
+++ b/apps/systray/java/build.xml
@@ -65,6 +65,8 @@
                 <attribute name="Build-Date" value="${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 3143f550c92979fd9e76c3cd6f0770f78bacc2d0..1f301ae591b7982b0dcf06ecc6bd1b7b33dce65e 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 f0caf6b8610222a1f6c04477548422f06b530345..e73ff9036eaea4fd1d2e7716b6b4ce35e7a56a51 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="${javac.version}" />
             </manifest>
         </jar>
     </target>
diff --git a/installer/tools/java/build.xml b/installer/tools/java/build.xml
index c7dff1b4e9cf3b28956732c2ef2368ebdd37d94d..40d8514a77570e640227ede7ae38bc3463649c50 100644
--- a/installer/tools/java/build.xml
+++ b/installer/tools/java/build.xml
@@ -38,6 +38,8 @@
                 <attribute name="Built-By" value="${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 79c3d5d53d23502ac0e7d34d7b5f227748ed9951..7097d8a77d7d6cf3eb20f9e6c0e8d87556d805ef 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>