When you visit a Web page, your browser (Internet Explorer/Mozilla Firefox/Opera/Chrome) sends the user-agent string to the Travian site. This string indicates which browser you are using, its version number, and details about your system, such as operating system and version.
User-agent string examples:
Opera/9.25 (Windows NT 6.0; U; en)
Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0
You can view your User Agent String here at WhatsMyUserAgent.com
Copy it than open Settings->Connection and paste into textbox like on picture below.