The servers will be coming down at 6am (pacific) for an update. The estimated downtime is 1.5 hours.
The primary changes are several server performance optimizations, as well as a fix for a server crash that occurred multiple times over the past weekend. We've also included mechanisms that will provide us with more granular server debug information during peak-population times. Our first round of server performance profiling will begin on the EU servers tomorrow (between 4 - 8pm GMT) and will continue on the US servers during the NA prime-time. This performance profiling should be transparent to players.
Source: Game Update Notes
