Tier V would lose an order.

[quote=Pepperm1nts]
Is it possible for a nation to rise in Tiers? I'm happy being Tier II, but I'm still curious.
[/quote]

Yeah. As I said, your tier is not only determined by your power but also by how relevant you are. If you get a bigger navy and do more in international politics, you'll rise a tier. For instance, the USA is at tier II but is in a position to get to Tier I very quickly.

[quote=solamelike]
btw what is a treaty order? Is that like when you have a treaty giving away land you will use that order?
[/quote]

An order reserved for a treaty.