diff --git a/java/src/com/android/inputmethod/latin/DictionaryWriter.java b/java/src/com/android/inputmethod/latin/DictionaryWriter.java
index 3df2a2b63..f1a054162 100644
--- a/java/src/com/android/inputmethod/latin/DictionaryWriter.java
+++ b/java/src/com/android/inputmethod/latin/DictionaryWriter.java
@@ -37,9 +37,9 @@ import java.util.Map;
  * An in memory dictionary for memorizing entries and writing a binary dictionary.
  */
 public class DictionaryWriter extends AbstractDictionaryWriter {
-    private static final int BINARY_DICT_VERSION = 3;
+    private static final int BINARY_DICT_VERSION = 2;
     private static final FormatSpec.FormatOptions FORMAT_OPTIONS =
-            new FormatSpec.FormatOptions(BINARY_DICT_VERSION, true /* supportsDynamicUpdate */);
+            new FormatSpec.FormatOptions(BINARY_DICT_VERSION, false /* supportsDynamicUpdate */);
 
     private FusionDictionary mFusionDictionary;
 
diff --git a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
index 056054273..17cb7151d 100644
--- a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
+++ b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
@@ -131,7 +131,8 @@ abstract public class ExpandableBinaryDictionary extends Dictionary {
     protected abstract boolean hasContentChanged();
 
     protected boolean isValidBinaryDictFormatVersion(final int formatVersion) {
-        return true;
+        // TODO: Use ver4 format.
+        return formatVersion == 2;
     }
 
     protected String getFileNameExtentionToOpenDict() {