How to avoid IIS and ASP.NET version disclosure during 404 response in ASP.NET with C#?

<rewrite>
        <outboundRules>
            <rule name="ChangeServerHeader">
                <match serverVariable="RESPONSE_SERVER" pattern=".*" />
                <action type="Rewrite" value="Private Server" />
            </rule>
        </outboundRules>
    </rewrite>

protected void Application_PreSendRequestHeaders(object sender, EventArgs e)
{
     var app = sender as HttpApplication;
     if (app != null && app.Context != null)
     {
          app.Context.Response.Headers.Remove("Server");
      }
}