At 7am PDT on Thursday, May 19 all SOE login servers, forum account access and more will be unavailable during a 2 hour maintenance. Here is the official announcement:

Beginning at 7 AM PDT on Thursday May 19, 2011, the Login Server, SOE Account and Commerce flow and the Station Store will be unavailable due to maintenance. We expect this maintenance to take approximately 2 hours. This may also cause some forum accounts to temporarily lose permissions, due to the inability to verify account status while the maintenance is taking place. This is only temporary and normal permissions will return automatically once the maintenance is complete.

We apologize for this interruption and will resume all affected services as soon as the maintenance is completed.

Source: EQ Players

Amnerys on the EQII Forums later included a warning about zoning:

Update: If you zone during this maintenance, you could lose connection and not be able to log back in.