diff --git a/changelog/unreleased/PR#4344-update-com-diffplug-spotless.yml b/changelog/unreleased/PR#4344-update-com-diffplug-spotless.yml
new file mode 100644
index 00000000000..80171ddfba4
--- /dev/null
+++ b/changelog/unreleased/PR#4344-update-com-diffplug-spotless.yml
@@ -0,0 +1,7 @@
+title: Update com.diffplug.spotless to v8.4.0
+type: dependency_update
+authors:
+- name: solrbot
+links:
+- name: PR#4344
+  url: https://github.com/apache/solr/pull/4344
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 7018c17a31e..e8877a623de 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -79,7 +79,7 @@ cutterslade-analyze = "1.10.0"
 cuvs-java = "25.10.0"
 cuvs-lucene = "25.10.0"
 decompose = "3.4.0"
-diffplug-spotless = "8.3.0"
+diffplug-spotless = "8.4.0"
 # @keep Use for dockerfile JRE version
 dockerfile-baseimage-java = "25"
 dropwizard-metrics = "4.2.33"