diff --git a/src/test/java/org/codelibs/fesen/client/Elasticsearch8ClientTest.java b/src/test/java/org/codelibs/fesen/client/Elasticsearch8ClientTest.java
index b148ee0..de5969d 100644
--- a/src/test/java/org/codelibs/fesen/client/Elasticsearch8ClientTest.java
+++ b/src/test/java/org/codelibs/fesen/client/Elasticsearch8ClientTest.java
@@ -110,7 +110,7 @@
 class Elasticsearch8ClientTest {
     static final Logger logger = Logger.getLogger(Elasticsearch8ClientTest.class.getName());
 
-    static final String version = "8.15.3";
+    static final String version = "8.15.4";
 
     static final String imageTag = "docker.elastic.co/elasticsearch/elasticsearch:" + version;