diff --git a/Scripts/Format/VRMFormat.cs b/Scripts/Format/VRMFormat.cs
index 0d00a88b5..ebff260fc 100644
--- a/Scripts/Format/VRMFormat.cs
+++ b/Scripts/Format/VRMFormat.cs
@@ -52,6 +52,7 @@ namespace VRM
 
         protected override void SerializeMembers(JsonFormatter f)
         {
+            f.KeyValue(() => extensionsUsed);
             f.KeyValue(() => extensions);
             base.SerializeMembers(f);
         }
diff --git a/UniGLTF b/UniGLTF
index b3e5b194b..b08b853c1 160000
--- a/UniGLTF
+++ b/UniGLTF
@@ -1 +1 @@
-Subproject commit b3e5b194b26a79c0606f92c0565f82ceb5a81b71
+Subproject commit b08b853c1a3f758d6adff8089ee7ca606e020582