diff --git a/smack-core/src/main/java/org/jivesoftware/smack/packet/CustomAttributesExtension.java b/smack-core/src/main/java/org/jivesoftware/smack/packet/CustomAttributesExtension.java
index b120f75d75..06287cf54c 100644
--- a/smack-core/src/main/java/org/jivesoftware/smack/packet/CustomAttributesExtension.java
+++ b/smack-core/src/main/java/org/jivesoftware/smack/packet/CustomAttributesExtension.java
@@ -2,7 +2,7 @@
  *
  * Copyright 2016 Jules Tréhorel
  *
- * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
+ * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
@@ -32,7 +32,7 @@
  *
  * @author Jules Tréhorel
  */
-public class CustomAttributesExtension implements ExtensionElement {
+public final class CustomAttributesExtension implements ExtensionElement {
     public final static String NAME = "customAttributes";
     public final static String NAMESPACE = "http://smack.jivesoftware.com";