diff --git a/java/src/com/android/inputmethod/latin/makedict/DictionaryHeader.java b/java/src/com/android/inputmethod/latin/makedict/DictionaryHeader.java
index 3f9ffd285..fa7c2c417 100644
--- a/java/src/com/android/inputmethod/latin/makedict/DictionaryHeader.java
+++ b/java/src/com/android/inputmethod/latin/makedict/DictionaryHeader.java
@@ -38,12 +38,8 @@ public final class DictionaryHeader {
     public static final String DICTIONARY_DATE_KEY = "date";
     public static final String HAS_HISTORICAL_INFO_KEY = "HAS_HISTORICAL_INFO";
     public static final String USES_FORGETTING_CURVE_KEY = "USES_FORGETTING_CURVE";
-    public static final String FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP_KEY =
-            "FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP";
     public static final String FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID_KEY =
             "FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID";
-    public static final String FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS_KEY =
-            "FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS";
     public static final String MAX_UNIGRAM_COUNT_KEY = "MAX_UNIGRAM_COUNT";
     public static final String MAX_BIGRAM_COUNT_KEY = "MAX_BIGRAM_COUNT";
     public static final String ATTRIBUTE_VALUE_TRUE = "1";