Follow the video below on how to update your server:
Bukkit is currently not updated to 1.7.2 yet, we expect it to be updated within the next couple of days but there is no ETA, watch the version column on this page for 1.7.2. If it appears and we have still not posted an announcement stating we have updated Bukkit to 1.7.2 then please let us know via live chat or ticket.