Download the new RouterOS 5.18 release over the torrent network: http://www.mikrotik.com/download/routeros-ALL-5.18.torrent
Otherwise please visit http://www.mikrotik.com/download to pick exact version!
5.18 changelog:
*) fixed upgrade problem when it failed with error "disk is too small" while there was plenty of space left;
*) fix health and poe access reliability on OmniTIK UPA and RB750UP boards;
*) sstp - improve initial handshake to better handle many new connections;
*) wireless - do not use bridge and WDS mode on AP-AP links, causes loops;
*) dhcp ipv6 pd client - fixed ipv6 pool creation after reboot;
*) dhcp ipv6 pd client - added option add-default-route;
*) sstp - fixed connection idle time reporting;
*) fix bad block count not to increase on Samsung K9F1208U0C nand;
*) snmp - fix dhcp lease table, snmp reported an incorrect information when a static lease had configured different address than current active address, this should also solve problem with dude polling same leases over and over again;
*) fix RB1100 crash on interface disable/l2mtu change/reboot;
*) dns could not resolve some domain names, was ignoring replies with DNAME RRs;
*) fix firewall log action - sometimes was not logging mac addr;