On 11/6 at 3 AM PST for NA and 3:00 CET for EUNE the servers will be coming down for a brief maintenance.
Here's schangtothe, a NOC technician, with the NA version of the announcement:
"On 11/06/13, starting at 01:00 PST, ranked queues will be disabled in preparation for a provider maintenance. Following the provider maintenance, at 03:00 PST, the servers will be shut down and all games currently in progress will end in a draw and stats will not be recorded. We estimate the battlegrounds will be unavailable for up to 4 hours.
At this time we’ll also be fixing a few key bugs we found with the 3.13 deploy:
• Fixed a bug where Kindlegem was costing 100 more gold than its listed price (the price has been reverted to 850g)
• Fixed a bug where certain players couldn’t transfer servers in this patch
• Fixed a bug where vintage owners of Haunting Nocturne were not properly getting their limited edition skin overlays on loading screen"
Other server maintenance threads: LAS, LAN, BR, TR, RU, OCE