Upgrade & Repair

Upgrade and Repair is a function used to, you won't believe, to upgrade and repair weapons.

You need two weapons, and one of them (in the destroyed, or bottom slot) is irreversibly lost. The one in the upper slot is repaired or upgraded.

Upgrade
Upgrade is simple - you pick two identical weapons with the same level and 100% durability and merge them, receiving one, but of a higher level.

Why is this even a thing, if the weapon stats rise a little and you sacrifice a whole same weapon? Because the maximum amount of soldiers is 16 in the House mode, and you can't have more than 16 active weapons, so do your best to make them as good as you can.

The maximum level is 10, however, it is extremely hard to reach it. That is because with each upgrade, you need two weapons, and to create a level 10 one you need 2 level 9, or 4 level 8, or 8 level 7, or 16 level 6, or 32 level 5, or 64 level 4, or 128 level 3, or 256 level 2, or 512 level 1, or  1024  basic.

That is A LOT.

Repair
Repair is harder to plan, but easier to do. Via some equation it transfers leftover durability of the destroyed weapon to additional durability to the repaired weapon.

Usually, it follows this disequation: melee < pistols < shotguns < sniper rifles < assault rifles