From the EQ2 Forums:
Most US EverQuest 2 Servers will come down on Tuesday, June 25, at 7:00 am Pacific Time* for an update. The expected downtime is one hour.
The Guk, Everfrost, Crushbone, Permafrost and Oasis servers will have an extended downtime, coming down earlier at 5:30 am Pacific Time.
The EU EQ2 Servers will come down on Tuesday, June 25, at 9:00 pm Pacific Time*, and the expected downtime is two hours.