Blocking Browsers that use old WebSocket Specification

Some browsers implements very old WebSocket. You can force those browsers to fallback to another transport to prevent some unexpected issues on the server. All you need to do is to add the WebSocketHandshakeFilter:

   <filter>
        <filter-name>WebSocketHandshakeFilter</filter-name>
        <filter-class>org.atmosphere.websocket.WebSocketHandshakeFilter</filter-class>
        <init-param>
            <param-name>org.atmosphere.websocket.bannedVersion</param-name>
            <param-value>-1</param-value>
        </init-param>
    </filter>

Value can be -1 for very old, or specification version like 13, 10. etc.

See also: How to use the older WebSocket draft-00/hybi-00/hixie-76 protocol