diff --git a/.gitmodules b/.gitmodules
index 72b2fc1fd..20324e940 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,7 +4,7 @@
 [submodule "providers/flagd/test-harness"]
 	path = providers/flagd/test-harness
 	url = https://github.com/open-feature/test-harness.git
-	branch = v1.3.3
+	branch = v1.4.0
 [submodule "providers/flagd/spec"]
 	path = providers/flagd/spec
 	url = https://github.com/open-feature/spec.git
diff --git a/providers/flagd/test-harness b/providers/flagd/test-harness
index 1252f5145..9cc25e953 160000
--- a/providers/flagd/test-harness
+++ b/providers/flagd/test-harness
@@ -1 +1 @@
-Subproject commit 1252f5145324cfd700c4e5dc35130551904a8f05
+Subproject commit 9cc25e95301881032a1a45eb5cb7cb6684071edf