diff --git a/bukkit/src/main/java/net/momirealms/craftengine/bukkit/entity/data/EntityDataValue.java b/bukkit/src/main/java/net/momirealms/craftengine/bukkit/entity/data/EntityDataValue.java
index baae1cf12..c5db7a6e3 100644
--- a/bukkit/src/main/java/net/momirealms/craftengine/bukkit/entity/data/EntityDataValue.java
+++ b/bukkit/src/main/java/net/momirealms/craftengine/bukkit/entity/data/EntityDataValue.java
@@ -30,6 +30,7 @@ public class EntityDataValue {
     public static final Object Serializers$OPTIONAL_BLOCK_POS;
     public static final Object Serializers$DIRECTION;
     public static final Object Serializers$OPTIONAL_UUID;
+    public static final Object Serializers$OPTIONAL_LIVING_ENTITY_REFERENCE;
     public static final Object Serializers$OPTIONAL_GLOBAL_POS;
     public static final Object Serializers$COMPOUND_TAG;
     public static final Object Serializers$VILLAGER_DATA;
@@ -64,7 +65,10 @@ public class EntityDataValue {
             Serializers$BLOCK_POS = initSerializersByName("BLOCK_POS");
             Serializers$OPTIONAL_BLOCK_POS = initSerializersByName("OPTIONAL_BLOCK_POS");
             Serializers$DIRECTION = initSerializersByName("DIRECTION");
-            Serializers$OPTIONAL_UUID = initSerializersByName("OPTIONAL_UUID");
+            if (!VersionHelper.isVersionNewerThan1_21_5()) Serializers$OPTIONAL_UUID = initSerializersByName("OPTIONAL_UUID");
+            else Serializers$OPTIONAL_UUID = null;
+            if (VersionHelper.isVersionNewerThan1_21_5()) Serializers$OPTIONAL_LIVING_ENTITY_REFERENCE = initSerializersByName("OPTIONAL_LIVING_ENTITY_REFERENCE");
+            else Serializers$OPTIONAL_LIVING_ENTITY_REFERENCE = null;
             Serializers$OPTIONAL_GLOBAL_POS = initSerializersByName("OPTIONAL_GLOBAL_POS");
             Serializers$COMPOUND_TAG = initSerializersByName("COMPOUND_TAG");
             Serializers$VILLAGER_DATA = initSerializersByName("VILLAGER_DATA");