Implementing an Expansion

Turning on an expansion looks a lot like the original launch day. The current players will be rushing out to buy the expansion on the first day, to get their hands on the new content, so the servers will see an unusual spike in the number of simultaneous users, similar to what happened the day the game went live.

Thus, the day an expansion hits the retail shelves should be treated like launch day, and the two to four weeks afterward should be treated like a launch phase: Rest the team beforehand, anticipate server and bandwidth overloads, and dust off and review the emergency plans from launch day.