Feldon 
The War of Zek, or Game Update 61, will go live on Thursday, August 25, 2011. The US servers will be offline at the usual update time of 7:00 am PDT and are expected to be back online around 10:00 am PDT. UK worlds will be updated at 3:00 PM London Time. The estimated downtime will be 3 hours.
- Pacific Daylight Time (PDT): 7:00am-10:00am
- Eastern Daylight Time (EDT): 10:00am-01:00pm
- British Summer Time (BST): 03:00pm-06:00pm
- Central Europe Time (CET): 04:00pm-07:00pm
We will post the Game Update 61: Update Notes as soon as we have them.
Still no date for the European servers ??
This is a notification that UK worlds will be updated at 3:00 PM London Time on the 08/25/2011. The estimated downtime will be 3 hours.
http://forums.station.sony.com/eq2/posts/list.m?topic_id=505429
4pm CET for Europe, same day, according to EQ2Zam. Downtime maybe up to 3h (probably due to translations).
Looks to me like all servers are getting updated at the same time. I added update times for Europe.