Just thought I would through this out there...
When you declare war it says that: "Wars automatically expire after 7 days"
But if you look at the "Wars Across the Globe" screen, it looks like wars last 8 days.
Example:
Nations that declared war on 11/4 were able to fight through 11/11. The wars ended after server change on the 12th. That is 8 days of fighting right?
If you look at wars started on 11/5...they are still active. So they were able to fight on the 5th, 6th, 7th, 8th, 9th, 10th, 11th and 12th. 8 days of fighting.
Like I said...just thought I would throw it out there. Maybe that is the way it is supposed to be.