diff --git a/Plugin.php b/Plugin.php
index d05f8c6..aa77487 100644
--- a/Plugin.php
+++ b/Plugin.php
@@ -1,6 +1,6 @@
 <?php
 /*
- * Copyright 2018 the original author or authors.
+ * Copyright 2018, 2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
diff --git a/js/refresh.js b/js/refresh.js
index 2605e8e..b17b6f9 100644
--- a/js/refresh.js
+++ b/js/refresh.js
@@ -1,3 +1,20 @@
+/*!
+ * This file is a part of Mibew Advanced Button Plugin
+ *
+ * Copyright 2014, 2018, 2021 the original author or authors.
+ *
+ * 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
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 (function(Mibew) {
     Mibew.APIFunctions.refreshButton = function(data) {