At 9.00 CEST on Tuesday, July 5th, the forums will be unavailable since we are migrating to Xenforo (another, better, forum software - we currently use vBulletin).
Considering the size of the forum (in terms of amounts of posts), this process may take many hours to finish, though we hope it will finish smoothly.
We cannot offer a definite timetable for how long the migration will take, but from the migration of other market forums it's likely the minimum will be 10 hours but it may take longer than 24h.
We apologize for any inconvenience caused.
The Tribal Wars Team