You may run wars any way you choose. If both sides agree, they may (at any point during the war) add, remove, or update any of the rules below.
If both parties agree, you may run a war based on an entirely separate set of war rules. It’s your call. If neither side comes to such an agreement then the provided war rules serve as a fallback.
You may make alterations at any point throughout the war—the only condition is that both sides must agree. Additions and revisions to the rules will last for the duration of the war.