diff --git a/tools/makedict/src/com/android/inputmethod/latin/BinaryDictInputOutput.java b/tools/makedict/src/com/android/inputmethod/latin/BinaryDictInputOutput.java
index 7aadc67..65b9074 100644
--- a/tools/makedict/src/com/android/inputmethod/latin/BinaryDictInputOutput.java
+++ b/tools/makedict/src/com/android/inputmethod/latin/BinaryDictInputOutput.java
@@ -112,8 +112,10 @@
      */
 
     private static final int MAGIC_NUMBER = 0x78B1;
-    private static final int VERSION = 1;
-    private static final int MAXIMUM_SUPPORTED_VERSION = VERSION;
+    private static final int MINIMUM_SUPPORTED_VERSION = 1;
+    private static final int MAXIMUM_SUPPORTED_VERSION = 2;
+    private static final int FIRST_VERSION_WITH_HEADER_SIZE = 2;
+
     // No options yet, reserved for future use.
     private static final int OPTIONS = 0;
 
@@ -797,9 +799,10 @@
      *
      * @param destination the stream to write the binary data to.
      * @param dict the dictionary to write.
+     * @param version the version of the format to write, currently either 1 or 2.
      */
-    public static void writeDictionaryBinary(OutputStream destination, FusionDictionary dict)
-            throws IOException {
+    public static void writeDictionaryBinary(OutputStream destination, FusionDictionary dict,
+            final int version) throws IOException, UnsupportedFormatException {
 
         // Addresses are limited to 3 bytes, so we'll just make a 16MB buffer. Since addresses
         // can be relative to each node, the structure itself is not limited to 16MB at all, but
@@ -811,16 +814,30 @@
         final byte[] buffer = new byte[1 << 24];
         int index = 0;
 
+        if (version < MINIMUM_SUPPORTED_VERSION || version > MAXIMUM_SUPPORTED_VERSION) {
+            throw new UnsupportedFormatException("Requested file format version " + version
+                    + ", but this implementation only supports versions "
+                    + MINIMUM_SUPPORTED_VERSION + " through " + MAXIMUM_SUPPORTED_VERSION);
+        }
+
         // Magic number in big-endian order.
         buffer[index++] = (byte) (0xFF & (MAGIC_NUMBER >> 8));
         buffer[index++] = (byte) (0xFF & MAGIC_NUMBER);
         // Dictionary version.
-        buffer[index++] = (byte) (0xFF & VERSION);
+        buffer[index++] = (byte) (0xFF & version);
         // Options flags
         buffer[index++] = (byte) (0xFF & (OPTIONS >> 8));
         buffer[index++] = (byte) (0xFF & OPTIONS);
+        if (version >= FIRST_VERSION_WITH_HEADER_SIZE) {
+            final int headerSizeOffset = index;
+            index += 3; // Size of the header size
 
-        // Should we include the locale and title of the dictionary ?
+            // Write out the header contents here.
+
+            buffer[headerSizeOffset] = (byte) (0xFF & (index >> 16));
+            buffer[headerSizeOffset + 1] = (byte) (0xFF & (index >> 8));
+            buffer[headerSizeOffset + 2] = (byte) (0xFF & (index >> 0));
+        }
 
         destination.write(buffer, 0, index);
         index = 0;
@@ -1125,7 +1142,16 @@
         // Read options
         source.readUnsignedShort();
 
-        long headerSize = source.getFilePointer();
+        final long headerSize;
+        if (version < FIRST_VERSION_WITH_HEADER_SIZE) {
+            headerSize = source.getFilePointer();
+        } else {
+            headerSize = source.readUnsignedByte() << 16 + source.readUnsignedByte() << 8
+                    + source.readUnsignedByte();
+            // read the header body
+            source.seek(headerSize);
+        }
+
         Map<Integer, Node> reverseNodeMapping = new TreeMap<Integer, Node>();
         Map<Integer, CharGroup> reverseGroupMapping = new TreeMap<Integer, CharGroup>();
         final Node root = readNode(source, headerSize, reverseNodeMapping, reverseGroupMapping);
diff --git a/tools/makedict/src/com/android/inputmethod/latin/DictionaryMaker.java b/tools/makedict/src/com/android/inputmethod/latin/DictionaryMaker.java
index 2fcd575..fbfa424 100644
--- a/tools/makedict/src/com/android/inputmethod/latin/DictionaryMaker.java
+++ b/tools/makedict/src/com/android/inputmethod/latin/DictionaryMaker.java
@@ -41,6 +41,7 @@
         private final static String OPTION_INPUT_BIGRAM_XML = "-b";
         private final static String OPTION_INPUT_SHORTCUT_XML = "-c";
         private final static String OPTION_OUTPUT_BINARY = "-d";
+        private final static String OPTION_OUTPUT_BINARY_FORMAT_VERSION_1 = "-d1";
         private final static String OPTION_OUTPUT_XML = "-x";
         private final static String OPTION_HELP = "-h";
         public final String mInputBinary;
@@ -48,11 +49,27 @@
         public final String mInputShortcutXml;
         public final String mInputBigramXml;
         public final String mOutputBinary;
+        public final String mOutputBinaryFormat1;
         public final String mOutputXml;
 
-        private void checkIntegrity() {
+        private void checkIntegrity() throws IOException {
             checkHasExactlyOneInput();
             checkHasAtLeastOneOutput();
+            checkNotSameFile(mInputBinary, mOutputBinary);
+            checkNotSameFile(mInputBinary, mOutputBinaryFormat1);
+            checkNotSameFile(mInputBinary, mOutputXml);
+            checkNotSameFile(mInputUnigramXml, mOutputBinary);
+            checkNotSameFile(mInputUnigramXml, mOutputBinaryFormat1);
+            checkNotSameFile(mInputUnigramXml, mOutputXml);
+            checkNotSameFile(mInputShortcutXml, mOutputBinary);
+            checkNotSameFile(mInputShortcutXml, mOutputBinaryFormat1);
+            checkNotSameFile(mInputShortcutXml, mOutputXml);
+            checkNotSameFile(mInputBigramXml, mOutputBinary);
+            checkNotSameFile(mInputBigramXml, mOutputBinaryFormat1);
+            checkNotSameFile(mInputBigramXml, mOutputXml);
+            checkNotSameFile(mOutputBinary, mOutputBinaryFormat1);
+            checkNotSameFile(mOutputBinary, mOutputXml);
+            checkNotSameFile(mOutputBinaryFormat1, mOutputXml);
         }
 
         private void checkHasExactlyOneInput() {
@@ -67,26 +84,40 @@
         }
 
         private void checkHasAtLeastOneOutput() {
-            if (null == mOutputBinary && null == mOutputXml) {
+            if (null == mOutputBinary && null == mOutputBinaryFormat1 && null == mOutputXml) {
                 throw new RuntimeException("No output specified");
             }
         }
 
+        /**
+         * Utility method that throws an exception if path1 and path2 point to the same file.
+         */
+        private static void checkNotSameFile(final String path1, final String path2)
+                throws IOException {
+            if (null == path1 || null == path2) return;
+            if (new File(path1).getCanonicalPath().equals(new File(path2).getCanonicalPath())) {
+                throw new RuntimeException(path1 + " and " + path2 + " are the same file: "
+                        + " refusing to process.");
+            }
+        }
+
         private void displayHelp() {
             MakedictLog.i("Usage: makedict "
                     + "[-s <unigrams.xml> [-b <bigrams.xml>] [-c <shortcuts.xml>] "
-                    + "| -s <binary input>] "
-                    + "[-d <binary output>] [-x <xml output>] [-2]\n"
+                    + "| -s <binary input>] [-d <binary output format version 2>] "
+                    + "[-d1 <binary output format version 1>] [-x <xml output>] [-2]\n"
                     + "\n"
                     + "  Converts a source dictionary file to one or several outputs.\n"
                     + "  Source can be an XML file, with an optional XML bigrams file, or a\n"
                     + "  binary dictionary file.\n"
-                    + "  Both binary and XML outputs are supported. Both can be output at\n"
-                    + "  the same time but outputting several files of the same type is not\n"
-                    + "  supported.");
+                    + "  Binary version 1 (Ice Cream Sandwich), 2 (Jelly Bean) and XML outputs\n"
+                    + "  are supported. All three can be output at the same time, but the same\n"
+                    + "  output format cannot be specified several times. The behavior is\n"
+                    + "  unspecified if the same file is specified for input and output, or for\n"
+                    + "  several outputs.");
         }
 
-        public Arguments(String[] argsArray) {
+        public Arguments(String[] argsArray) throws IOException {
             final LinkedList<String> args = new LinkedList<String>(Arrays.asList(argsArray));
             if (args.isEmpty()) {
                 displayHelp();
@@ -96,6 +127,7 @@
             String inputShortcutXml = null;
             String inputBigramXml = null;
             String outputBinary = null;
+            String outputBinaryFormat1 = null;
             String outputXml = null;
 
             while (!args.isEmpty()) {
@@ -126,6 +158,8 @@
                             inputBigramXml = filename;
                         } else if (OPTION_OUTPUT_BINARY.equals(arg)) {
                             outputBinary = filename;
+                        } else if (OPTION_OUTPUT_BINARY_FORMAT_VERSION_1.equals(arg)) {
+                            outputBinaryFormat1 = filename;
                         } else if (OPTION_OUTPUT_XML.equals(arg)) {
                             outputXml = filename;
                         } else {
@@ -152,6 +186,7 @@
             mInputShortcutXml = inputShortcutXml;
             mInputBigramXml = inputBigramXml;
             mOutputBinary = outputBinary;
+            mOutputBinaryFormat1 = outputBinaryFormat1;
             mOutputXml = outputXml;
             checkIntegrity();
         }
@@ -231,9 +266,13 @@
      * @throws IOException if one of the output files can't be written to.
      */
     private static void writeOutputToParsedArgs(final Arguments args, final FusionDictionary dict)
-            throws FileNotFoundException, IOException {
+            throws FileNotFoundException, IOException, UnsupportedFormatException,
+            IllegalArgumentException {
         if (null != args.mOutputBinary) {
-            writeBinaryDictionary(args.mOutputBinary, dict);
+            writeBinaryDictionary(args.mOutputBinary, dict, 2);
+        }
+        if (null != args.mOutputBinaryFormat1) {
+            writeBinaryDictionary(args.mOutputBinaryFormat1, dict, 1);
         }
         if (null != args.mOutputXml) {
             writeXmlDictionary(args.mOutputXml, dict);
@@ -245,13 +284,16 @@
      *
      * @param outputFilename the name of the file to write to.
      * @param dict the dictionary to write.
+     * @param version the binary format version to use.
      * @throws FileNotFoundException if the output file can't be created.
      * @throws IOException if the output file can't be written to.
      */
     private static void writeBinaryDictionary(final String outputFilename,
-            final FusionDictionary dict) throws FileNotFoundException, IOException {
+            final FusionDictionary dict, final int version)
+            throws FileNotFoundException, IOException, UnsupportedFormatException {
         final File outputFile = new File(outputFilename);
-        BinaryDictInputOutput.writeDictionaryBinary(new FileOutputStream(outputFilename), dict);
+        BinaryDictInputOutput.writeDictionaryBinary(new FileOutputStream(outputFilename), dict,
+                version);
     }
 
     /**