Just to give some insight about how things normally progress here's the normal steps we go though.
1) Main server is stopped.
2) All componet source code is updated ( cvs/svn )
3) A full rebuild is started of all components
4) Database updated from an upgrade schema ( thank god for that, since database changes are a total pain )
5) A test client is packaged including new artwork/levels/sounds/whatever
6) New data is loaded into database for new items, equipment, quests, etc.
7) We test on the new server to figure out any obvious issues
8 ) An 'official' client is packaged
9) Data is placed in the updater system
10) Server restarted and released to the playing public.
Right now we are at around stage 5/6