diff --git a/Example/bin/Debug_Ubuntu/example.exe b/Example/bin/Debug_Ubuntu/example.exe
index a035389f..10d42ef5 100755
Binary files a/Example/bin/Debug_Ubuntu/example.exe and b/Example/bin/Debug_Ubuntu/example.exe differ
diff --git a/Example/bin/Debug_Ubuntu/websocket-sharp.dll b/Example/bin/Debug_Ubuntu/websocket-sharp.dll
index 8b213901..77a44851 100755
Binary files a/Example/bin/Debug_Ubuntu/websocket-sharp.dll and b/Example/bin/Debug_Ubuntu/websocket-sharp.dll differ
diff --git a/Example1/bin/Debug_Ubuntu/example1.exe b/Example1/bin/Debug_Ubuntu/example1.exe
index 44628063..308ef52d 100755
Binary files a/Example1/bin/Debug_Ubuntu/example1.exe and b/Example1/bin/Debug_Ubuntu/example1.exe differ
diff --git a/Example1/bin/Debug_Ubuntu/websocket-sharp.dll b/Example1/bin/Debug_Ubuntu/websocket-sharp.dll
index 8b213901..77a44851 100755
Binary files a/Example1/bin/Debug_Ubuntu/websocket-sharp.dll and b/Example1/bin/Debug_Ubuntu/websocket-sharp.dll differ
diff --git a/Example2/Chat.cs b/Example2/Chat.cs
index 5fd3c229..c7d0c011 100644
--- a/Example2/Chat.cs
+++ b/Example2/Chat.cs
@@ -13,7 +13,7 @@ namespace Example2 {
 
     private string getName()
     {
-      return QueryString.Exists("name")
+      return QueryString.Contains("name")
              ? QueryString["name"]
              : "anon#" + getNum();
     }
diff --git a/Example2/Echo.cs b/Example2/Echo.cs
index c7063c7d..130a934d 100644
--- a/Example2/Echo.cs
+++ b/Example2/Echo.cs
@@ -9,7 +9,7 @@ namespace Example2 {
   {
     protected override void OnMessage(MessageEventArgs e)
     {
-      var msg = QueryString.Exists("name")
+      var msg = QueryString.Contains("name")
               ? String.Format("'{0}' returns to {1}", e.Data, QueryString["name"])
               : e.Data;
       Send(msg);
diff --git a/Example2/bin/Debug_Ubuntu/example2.exe b/Example2/bin/Debug_Ubuntu/example2.exe
index 4a133c17..df2caad4 100755
Binary files a/Example2/bin/Debug_Ubuntu/example2.exe and b/Example2/bin/Debug_Ubuntu/example2.exe differ
diff --git a/Example2/bin/Debug_Ubuntu/websocket-sharp.dll b/Example2/bin/Debug_Ubuntu/websocket-sharp.dll
index 8b213901..77a44851 100755
Binary files a/Example2/bin/Debug_Ubuntu/websocket-sharp.dll and b/Example2/bin/Debug_Ubuntu/websocket-sharp.dll differ
diff --git a/Example3/Chat.cs b/Example3/Chat.cs
index 85e920fe..c6e887e7 100644
--- a/Example3/Chat.cs
+++ b/Example3/Chat.cs
@@ -13,7 +13,7 @@ namespace Example3 {
 
     private string getName()
     {
-      return QueryString.Exists("name")
+      return QueryString.Contains("name")
              ? QueryString["name"]
              : "anon#" + getNum();
     }
diff --git a/Example3/Echo.cs b/Example3/Echo.cs
index 48c36d64..365e1194 100644
--- a/Example3/Echo.cs
+++ b/Example3/Echo.cs
@@ -8,7 +8,7 @@ namespace Example3 {
   {
     protected override void OnMessage(MessageEventArgs e)
     {
-      var msg = QueryString.Exists("name")
+      var msg = QueryString.Contains("name")
               ? String.Format("'{0}' returns to {1}", e.Data, QueryString["name"])
               : e.Data;
       Send(msg);
diff --git a/Example3/bin/Debug_Ubuntu/Example3.exe b/Example3/bin/Debug_Ubuntu/Example3.exe
index 1faf9d14..82ebaa2d 100755
Binary files a/Example3/bin/Debug_Ubuntu/Example3.exe and b/Example3/bin/Debug_Ubuntu/Example3.exe differ
diff --git a/Example3/bin/Debug_Ubuntu/websocket-sharp.dll b/Example3/bin/Debug_Ubuntu/websocket-sharp.dll
index 8b213901..77a44851 100755
Binary files a/Example3/bin/Debug_Ubuntu/websocket-sharp.dll and b/Example3/bin/Debug_Ubuntu/websocket-sharp.dll differ
diff --git a/websocket-sharp/Ext.cs b/websocket-sharp/Ext.cs
index 2fc0b1a6..8c1bdb87 100644
--- a/websocket-sharp/Ext.cs
+++ b/websocket-sharp/Ext.cs
@@ -479,6 +479,60 @@ namespace WebSocketSharp {
                : value.IndexOfAny(chars) != -1;
     }
 
+    /// <summary>
+    /// Determines whether the specified <see cref="NameValueCollection"/> contains the entry
+    /// with the specified <paramref name="name"/>.
+    /// </summary>
+    /// <returns>
+    /// <c>true</c> if <paramref name="collection"/> contains the entry with <paramref name="name"/>;
+    /// otherwise, <c>false</c>.
+    /// </returns>
+    /// <param name="collection">
+    /// A <see cref="NameValueCollection"/> that contains the entries.
+    /// </param>
+    /// <param name="name">
+    /// A <see cref="string"/> that contains the key of the entry to find.
+    /// </param>
+    public static bool Contains(this NameValueCollection collection, string name)
+    {
+      return collection == null
+             ? false
+             : collection[name] != null;
+    }
+
+    /// <summary>
+    /// Determines whether the specified <see cref="NameValueCollection"/> contains the entry
+    /// with the specified both <paramref name="name"/> and <paramref name="value"/>.
+    /// </summary>
+    /// <returns>
+    /// <c>true</c> if <paramref name="collection"/> contains the entry with both <paramref name="name"/> and <paramref name="value"/>;
+    /// otherwise, <c>false</c>.
+    /// </returns>
+    /// <param name="collection">
+    /// A <see cref="NameValueCollection"/> that contains the entries.
+    /// </param>
+    /// <param name="name">
+    /// A <see cref="string"/> that contains the key of the entry to find.
+    /// </param>
+    /// <param name="value">
+    /// A <see cref="string"/> that contains the value of the entry to find.
+    /// </param>
+    public static bool Contains(this NameValueCollection collection, string name, string value)
+    {
+      if (collection == null)
+        return false;
+
+      var values = collection[name];
+      if (values == null)
+        return false;
+
+      foreach (string v in values.Split(','))
+        if (v.Trim().Equals(value, StringComparison.OrdinalIgnoreCase))
+          return true;
+
+      return false;
+    }
+
     /// <summary>
     /// Emit the specified <see cref="EventHandler"/> delegate if is not <see langword="null"/>.
     /// </summary>
@@ -551,56 +605,6 @@ namespace WebSocketSharp {
       return b == Convert.ToByte(c);
     }
 
-    /// <summary>
-    /// Determines whether the entry with the specified key exists in the specified <see cref="NameValueCollection"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if the entry with the <paramref name="name"/> exists in the <paramref name="collection"/>; otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="collection">
-    /// A <see cref="NameValueCollection"/> that contains the entries.
-    /// </param>
-    /// <param name="name">
-    /// A <see cref="string"/> that contains the key of the entry to find.
-    /// </param>
-    public static bool Exists(this NameValueCollection collection, string name)
-    {
-      return collection == null
-             ? false
-             : collection[name] != null;
-    }
-
-    /// <summary>
-    /// Determines whether the entry with the specified both key and value exists in the specified <see cref="NameValueCollection"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if the entry with the both <paramref name="name"/> and <paramref name="value"/> exists in the <paramref name="collection"/>; otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="collection">
-    /// A <see cref="NameValueCollection"/> that contains the entries.
-    /// </param>
-    /// <param name="name">
-    /// A <see cref="string"/> that contains the key of the entry to find.
-    /// </param>
-    /// <param name="value">
-    /// A <see cref="string"/> that contains the value of the entry to find.
-    /// </param>
-    public static bool Exists(this NameValueCollection collection, string name, string value)
-    {
-      if (collection == null)
-        return false;
-
-      var values = collection[name];
-      if (values == null)
-        return false;
-
-      foreach (string v in values.Split(','))
-        if (String.Compare(v.Trim(), value, true) == 0)
-          return true;
-
-      return false;
-    }
-
     /// <summary>
     /// Gets the absolute path from the specified <see cref="Uri"/>.
     /// </summary>
@@ -645,10 +649,9 @@ namespace WebSocketSharp {
     public static CookieCollection GetCookies(this NameValueCollection headers, bool response)
     {
       var name = response ? "Set-Cookie" : "Cookie";
-      if (headers == null || !headers.Exists(name))
-        return new CookieCollection();
-
-      return CookieCollection.Parse(headers[name], response);
+      return headers == null || !headers.Contains(name)
+             ? new CookieCollection()
+             : CookieCollection.Parse(headers[name], response);
     }
 
     /// <summary>
@@ -999,10 +1002,10 @@ namespace WebSocketSharp {
       if (protocol.Length == 0)
         throw new ArgumentException("Must not be empty.", "protocol");
 
-      if (!request.Headers.Exists("Upgrade", protocol))
+      if (!request.Headers.Contains("Upgrade", protocol))
         return false;
 
-      if (!request.Headers.Exists("Connection", "Upgrade"))
+      if (!request.Headers.Contains("Connection", "Upgrade"))
         return false;
 
       return true;
diff --git a/websocket-sharp/Handshake.cs b/websocket-sharp/Handshake.cs
index d5310b74..692dce96 100644
--- a/websocket-sharp/Handshake.cs
+++ b/websocket-sharp/Handshake.cs
@@ -72,12 +72,12 @@ namespace WebSocketSharp {
 
     public bool ContainsHeader(string name)
     {
-      return Headers.Exists(name);
+      return Headers.Contains(name);
     }
 
     public bool ContainsHeader(string name, string value)
     {
-      return Headers.Exists(name, value);
+      return Headers.Contains(name, value);
     }
 
     public string[] GetHeaderValues(string name)
diff --git a/websocket-sharp/Net/HttpListenerRequest.cs b/websocket-sharp/Net/HttpListenerRequest.cs
index bc8df327..c9278e2f 100644
--- a/websocket-sharp/Net/HttpListenerRequest.cs
+++ b/websocket-sharp/Net/HttpListenerRequest.cs
@@ -265,15 +265,15 @@ namespace WebSocketSharp.Net {
 					? false
 					: version < HttpVersion.Version11
 						? false
-						: !headers.Exists("Upgrade", "websocket")
+						: !headers.Contains("Upgrade", "websocket")
 							? false
-							: !headers.Exists("Connection", "Upgrade")
+							: !headers.Contains("Connection", "Upgrade")
 								? false
-								: !headers.Exists("Host")
+								: !headers.Contains("Host")
 									? false
-									: !headers.Exists("Sec-WebSocket-Key")
+									: !headers.Contains("Sec-WebSocket-Key")
 										? false
-										: headers.Exists("Sec-WebSocket-Version");
+										: headers.Contains("Sec-WebSocket-Version");
 			}
 		}
 
diff --git a/websocket-sharp/WebSocket.cs b/websocket-sharp/WebSocket.cs
index 77c2ed29..dca631ad 100644
--- a/websocket-sharp/WebSocket.cs
+++ b/websocket-sharp/WebSocket.cs
@@ -819,7 +819,7 @@ namespace WebSocketSharp {
              ? false
              : !isValidHostHeader()
                ? false
-               : _context.Headers.Exists("Sec-WebSocket-Version", _version);
+               : _context.Headers.Contains("Sec-WebSocket-Version", _version);
     }
 
     // As client
diff --git a/websocket-sharp/bin/Debug_Ubuntu/websocket-sharp.dll b/websocket-sharp/bin/Debug_Ubuntu/websocket-sharp.dll
index 8b213901..77a44851 100755
Binary files a/websocket-sharp/bin/Debug_Ubuntu/websocket-sharp.dll and b/websocket-sharp/bin/Debug_Ubuntu/websocket-sharp.dll differ