Download the new RouterOS 6.0beta3 release over the torrent network: http://www.mikrotik.com/download/routeros-ALL-6.0beta3.torrent
Otherwise please visit http://www.mikrotik.com/download to pick exact version!
6.0beta3 changelog:
*) installation - use much less space in storage (works well with 32MiB flash);
*) routerboard package is now merged with system package;
*) userman - use corresponding time zone data when showing date in console;
*) gps - init-string option;
*) ipsec - kill phase1 if ipsec-sa in responder expires due to system time change;
*) ipsec - rekey phase1 before expiration;
*) ipsec - when last ISAKMP-SA is deleted for the remote host remove related IPSec-SAs;
*) ipsec - send delete IPSec-SAs on shutdown/reboot;
*) user manager - fix user's active profile end time if it has unlimited validity, these users now won't be hidden from reports when date filters are in effect;
*) certificate validity is shown using local timezone offset;
*) fixed queue bit rate reporting;
*) fixed ipv6 firewall;
*) upgraded drivers and kernel (to linux-3.3.5);
*) added priority matcher to firewall;
*) added change-dscp from-priority and from-priority-to-high-3-bits options;
*) fixed router crash or hang when rebooting;
*) add snif-tzsp,snif-pc actions to ip/ipv6 firewall mangle;
*) traffic-generator improvements for multi core;