This patch is a follow-up to D3600 / rP25130.
Currently military structures, civic centres, fortresses, and siege walls have 35 pierce resistance. However, stone towers and walls have only 30, making them easier to destroy with projectiles. This patch raises their pierce resistance to 35 too.
Siege walls have a crush resistance of 5, more than any other structure; this is lowered to 3, the same value other defensive structures have.
Furthermore, the army camp has its resistance changed to the same values as siege walls; because +1 crush resistance makes it harder to destroy, its health is reduced by 10% to compensate.
See also D3756.