diff --git a/src/main/java/org/opensearch/knn/index/query/KNNQueryBuilder.java b/src/main/java/org/opensearch/knn/index/query/KNNQueryBuilder.java
index 11199f9d7..3429b2400 100644
--- a/src/main/java/org/opensearch/knn/index/query/KNNQueryBuilder.java
+++ b/src/main/java/org/opensearch/knn/index/query/KNNQueryBuilder.java
@@ -6,6 +6,7 @@
 package org.opensearch.knn.index.query;
 
 import lombok.extern.log4j.Log4j2;
+import org.opensearch.Version;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.knn.index.KNNMethodContext;
@@ -109,11 +110,11 @@ public KNNQueryBuilder(StreamInput in) throws IOException {
             fieldName = in.readString();
             vector = in.readFloatArray();
             k = in.readInt();
-            if (in.readBoolean()) {
-                filter = in.readNamedWriteable(QueryBuilder.class);
+            if (in.getVersion().onOrAfter(Version.V_2_4_0)) {
+                filter = in.readOptionalNamedWriteable(QueryBuilder.class);
             }
         } catch (IOException ex) {
-            throw new RuntimeException("[KNN] Unable to create KNNQueryBuilder: " + ex);
+            throw new RuntimeException("[KNN] Unable to create KNNQueryBuilder", ex);
         }
     }
 
@@ -184,12 +185,7 @@ protected void doWriteTo(StreamOutput out) throws IOException {
         out.writeString(fieldName);
         out.writeFloatArray(vector);
         out.writeInt(k);
-        if (filter != null) {
-            out.writeBoolean(true);
-            out.writeNamedWriteable(filter);
-        } else {
-            out.writeBoolean(false);
-        }
+        out.writeOptionalNamedWriteable(filter);
     }
 
     /**
diff --git a/src/test/java/org/opensearch/knn/index/query/KNNQueryBuilderTests.java b/src/test/java/org/opensearch/knn/index/query/KNNQueryBuilderTests.java
index f65fae030..bbf3f1442 100644
--- a/src/test/java/org/opensearch/knn/index/query/KNNQueryBuilderTests.java
+++ b/src/test/java/org/opensearch/knn/index/query/KNNQueryBuilderTests.java
@@ -47,6 +47,7 @@ public class KNNQueryBuilderTests extends KNNTestCase {
     private static final String FIELD_NAME = "myvector";
     private static final int K = 1;
     private static final TermQueryBuilder TERM_QUERY = QueryBuilders.termQuery("field", "value");
+    private static final float[] QUERY_VECTOR = new float[]{ 1.0f, 2.0f, 3.0f, 4.0f };
 
     public void testInvalidK() {
         float[] queryVector = { 1.0f, 1.0f };
@@ -222,9 +223,8 @@ public void testDoToQuery_InvalidFieldType() throws IOException {
     }
 
     public void testSerialization() throws Exception {
-        final float[] queryVector = { 1.0f, 2.0f, 3.0f, 4.0f };
 
-        final KNNQueryBuilder knnQueryBuilder = new KNNQueryBuilder(FIELD_NAME, queryVector, K);
+        final KNNQueryBuilder knnQueryBuilder = new KNNQueryBuilder(FIELD_NAME, QUERY_VECTOR, K);
 
         try (BytesStreamOutput output = new BytesStreamOutput()) {
             output.setVersion(Version.CURRENT);
@@ -233,17 +233,11 @@ public void testSerialization() throws Exception {
             try (StreamInput in = new NamedWriteableAwareStreamInput(output.bytes().streamInput(), writableRegistry())) {
                 in.setVersion(Version.CURRENT);
                 final QueryBuilder deserializedQuery = in.readNamedWriteable(QueryBuilder.class);
-                assertNotNull(deserializedQuery);
-                assertTrue(deserializedQuery instanceof KNNQueryBuilder);
-                final KNNQueryBuilder deserializedKnnQueryBuilder = (KNNQueryBuilder) deserializedQuery;
-                assertEquals(FIELD_NAME, deserializedKnnQueryBuilder.fieldName());
-                assertArrayEquals(queryVector, (float[]) deserializedKnnQueryBuilder.vector(), 0.0f);
-                assertEquals(K, deserializedKnnQueryBuilder.getK());
-                assertNull(deserializedKnnQueryBuilder.getFilter());
+                assertSerialization(deserializedQuery, true);
             }
         }
 
-        final KNNQueryBuilder knnQueryBuilderWithFilter = new KNNQueryBuilder(FIELD_NAME, queryVector, K, TERM_QUERY);
+        final KNNQueryBuilder knnQueryBuilderWithFilter = new KNNQueryBuilder(FIELD_NAME, QUERY_VECTOR, K, TERM_QUERY);
 
         try (BytesStreamOutput output = new BytesStreamOutput()) {
             output.setVersion(Version.CURRENT);
@@ -252,15 +246,35 @@ public void testSerialization() throws Exception {
             try (StreamInput in = new NamedWriteableAwareStreamInput(output.bytes().streamInput(), writableRegistry())) {
                 in.setVersion(Version.CURRENT);
                 final QueryBuilder deserializedQuery = in.readNamedWriteable(QueryBuilder.class);
-                assertNotNull(deserializedQuery);
-                assertTrue(deserializedQuery instanceof KNNQueryBuilder);
-                final KNNQueryBuilder deserializedKnnQueryBuilder = (KNNQueryBuilder) deserializedQuery;
-                assertEquals(FIELD_NAME, deserializedKnnQueryBuilder.fieldName());
-                assertArrayEquals(queryVector, (float[]) deserializedKnnQueryBuilder.vector(), 0.0f);
-                assertEquals(K, deserializedKnnQueryBuilder.getK());
-                assertNotNull(deserializedKnnQueryBuilder.getFilter());
-                assertEquals(TERM_QUERY, deserializedKnnQueryBuilder.getFilter());
+                assertSerialization(deserializedQuery, false);
             }
         }
+
+        //test serialization from < 2.4 versions
+        try (BytesStreamOutput output = new BytesStreamOutput()) {
+            output.setVersion(Version.V_2_3_0);
+            output.writeNamedWriteable(knnQueryBuilderWithFilter);
+
+            try (StreamInput in = new NamedWriteableAwareStreamInput(output.bytes().streamInput(), writableRegistry())) {
+                in.setVersion(Version.V_2_3_0);
+                final QueryBuilder deserializedQuery = in.readNamedWriteable(QueryBuilder.class);
+                assertSerialization(deserializedQuery, true);
+            }
+        }
+    }
+
+    private void assertSerialization(final QueryBuilder deserializedQuery, boolean assertFilterIsNull) {
+        assertNotNull(deserializedQuery);
+        assertTrue(deserializedQuery instanceof KNNQueryBuilder);
+        final KNNQueryBuilder deserializedKnnQueryBuilder = (KNNQueryBuilder) deserializedQuery;
+        assertEquals(FIELD_NAME, deserializedKnnQueryBuilder.fieldName());
+        assertArrayEquals(QUERY_VECTOR, (float[]) deserializedKnnQueryBuilder.vector(), 0.0f);
+        assertEquals(K, deserializedKnnQueryBuilder.getK());
+        if (assertFilterIsNull) {
+            assertNull(deserializedKnnQueryBuilder.getFilter());
+        } else {
+            assertNotNull(deserializedKnnQueryBuilder.getFilter());
+            assertEquals(TERM_QUERY, deserializedKnnQueryBuilder.getFilter());
+        }
     }
 }