diff --git a/java-client/src/main/java/co/elastic/clients/elasticsearch/_types/KnnRetriever.java b/java-client/src/main/java/co/elastic/clients/elasticsearch/_types/KnnRetriever.java
index 5dfb7d454..23efbc0e6 100644
--- a/java-client/src/main/java/co/elastic/clients/elasticsearch/_types/KnnRetriever.java
+++ b/java-client/src/main/java/co/elastic/clients/elasticsearch/_types/KnnRetriever.java
@@ -68,7 +68,8 @@ public class KnnRetriever extends RetrieverBase implements RetrieverVariant {
 
 	private final int k;
 
-	private final int numCandidates;
+	@Nullable
+	private final Integer numCandidates;
 
 	@Nullable
 	private final Float visitPercentage;
@@ -88,7 +89,7 @@ private KnnRetriever(Builder builder) {
 		this.queryVector = ApiTypeHelper.unmodifiable(builder.queryVector);
 		this.queryVectorBuilder = builder.queryVectorBuilder;
 		this.k = ApiTypeHelper.requireNonNull(builder.k, this, "k", 0);
-		this.numCandidates = ApiTypeHelper.requireNonNull(builder.numCandidates, this, "numCandidates", 0);
+		this.numCandidates = builder.numCandidates;
 		this.visitPercentage = builder.visitPercentage;
 		this.similarity = builder.similarity;
 		this.rescoreVector = builder.rescoreVector;
@@ -147,11 +148,12 @@ public final int k() {
 	}
 
 	/**
-	 * Required - Number of nearest neighbor candidates to consider per shard.
+	 * Number of nearest neighbor candidates to consider per shard.
 	 * <p>
 	 * API name: {@code num_candidates}
 	 */
-	public final int numCandidates() {
+	@Nullable
+	public final Integer numCandidates() {
 		return this.numCandidates;
 	}
 
@@ -210,9 +212,11 @@ protected void serializeInternal(JsonGenerator generator, JsonpMapper mapper) {
 		generator.writeKey("k");
 		generator.write(this.k);
 
-		generator.writeKey("num_candidates");
-		generator.write(this.numCandidates);
+		if (this.numCandidates != null) {
+			generator.writeKey("num_candidates");
+			generator.write(this.numCandidates);
 
+		}
 		if (this.visitPercentage != null) {
 			generator.writeKey("visit_percentage");
 			generator.write(this.visitPercentage);
@@ -248,6 +252,7 @@ public static class Builder extends RetrieverBase.AbstractBuilder<Builder> imple
 
 		private Integer k;
 
+		@Nullable
 		private Integer numCandidates;
 
 		@Nullable
@@ -351,11 +356,11 @@ public final Builder k(int value) {
 		}
 
 		/**
-		 * Required - Number of nearest neighbor candidates to consider per shard.
+		 * Number of nearest neighbor candidates to consider per shard.
 		 * <p>
 		 * API name: {@code num_candidates}
 		 */
-		public final Builder numCandidates(int value) {
+		public final Builder numCandidates(@Nullable Integer value) {
 			this.numCandidates = value;
 			return this;
 		}
diff --git a/java-client/src/main/java/co/elastic/clients/elasticsearch/doc-files/api-spec.html b/java-client/src/main/java/co/elastic/clients/elasticsearch/doc-files/api-spec.html
index 58cd654f1..f7d5a40b0 100644
--- a/java-client/src/main/java/co/elastic/clients/elasticsearch/doc-files/api-spec.html
+++ b/java-client/src/main/java/co/elastic/clients/elasticsearch/doc-files/api-spec.html
@@ -1537,7 +1537,7 @@
 'esql.put_dataset.Response': 'esql/put_dataset/PutDatasetResponse.ts#L22-L25',
 'esql.put_view.Request': 'esql/put_view/PutViewRequest.ts#L23-L49',
 'esql.put_view.Response': 'esql/put_view/PutViewResponse.ts#L22-L25',
-'esql.query.Request': 'esql/query/QueryRequest.ts#L28-L154',
+'esql.query.Request': 'esql/query/QueryRequest.ts#L28-L155',
 'esql.query.Response': 'esql/query/QueryResponse.ts#L22-L25',
 'features._types.Feature': 'features/_types/Feature.ts#L20-L23',
 'features.get_features.Request': 'features/get_features/GetFeaturesRequest.ts#L24-L56',
@@ -3641,10 +3641,10 @@
         if (hash.length > 1) {
             hash = hash.substring(1);
         }
-        window.location = "https://github.com/elastic/elasticsearch-specification/tree/3c9583e2aba3cf9be15537db19a95b47e37296c3/specification/" + (paths[hash] || "");
+        window.location = "https://github.com/elastic/elasticsearch-specification/tree/9e6a85519c8ff55a5977e03137a661c07532a232/specification/" + (paths[hash] || "");
     </script>
 </head>
 <body>
-    Please see the <a href="https://github.com/elastic/elasticsearch-specification/tree/3c9583e2aba3cf9be15537db19a95b47e37296c3/specification/">Elasticsearch API specification</a>.
+    Please see the <a href="https://github.com/elastic/elasticsearch-specification/tree/9e6a85519c8ff55a5977e03137a661c07532a232/specification/">Elasticsearch API specification</a>.
 </body>
 </html>