Notice: North American shards will be going down for a brief server restart every single day at 7:30AM PDT until further notice. Estimated downtime each day is 1hr.
European shards will go down every day at 1AM GMT.
The restarts are a temporarily solution to the issue that Vista users are currently experiencing where they will crash every 10min or so after the servers have been up for more than 24hrs.
If you have anything important scheduled around this time (like raids), please be aware of these daily resets.
[Source: CM Morgana]