MikroTik Routers and Wireless /
http://www.mikrotik.com/
Only Winbox 3.x will be supported from the RouterOS 6.20 apparently.
It was confirmed to Mikrotik about this, but it is an error to try to connect with Winbox2.x from RouterOS 6.20.
Be careful because it is written also in Release Note for this.
What’s new in 6.20rc6 (2014-Sep-08 10:16):
*) pppoe client – increase connection timeout to make connection establishment possible on busy pppoe server;
*) dhcp server – change default lease time from 3 days to 10 minutes to avoid running out of IPs;
*) ipsec – allow binding modeconf address to username;Winbox v3 is required for router’s configuration.
RouterOS 6.20からWinboxは3.x以上が必須になりました。Winbox v3 is required for router’s configuration. #routerboard #mikrotik
— Routerboard UG JP (@RBUG_JP) 2014, 9月 13
