Upgrading

Upgrading is a process in forts requiring an Upgrade Center, that allows you to upgrade an existing Devices or Weapons. Note that they don't have an upgrade.

Upgradable things
The buildings that can be upgraded are the Mine, Turbine, and a good amount of Weapons (Machine Gunner, Sniper, Mortar, Swarm Missiles, Flak, EMP Rocket).

Generalities
The process of upgrading needs ressources, and takes time to complete.

While a building is being upgraded, you cannot use it and it stops having any interactions with the game, despite existing and being possible to hit. This means a Mine will stop producing Metal when being upgraded, but it'll also stop consuming Energy.

Upgrading requires the possession of an Upgrade Center, which is pretty expensive (600 metal, 3000 energy) and takes time to build (60 seconds). This means you'll need to plan in advance if you want to go for upgrading stuff, or just sticking to not upgraded things.

When upgrading something, it generally becomes better at what it does. But on some cases, the upgraded building will lose something, like Mortar will lose the ability of putting things on Fire.

This means that sometimes, you don't want to upgrade what you have, because it's more useful how it currently is (mainly, you generally don't upgrade Machine Gunner nor Flak because it stops being automatic AA).

Other
Upgrading is essential in eco Rush, as it gives +50% production on your Devices when they all are upgraded.

Overdrive upgrades everything twice as fast, making it really strong when doing a strat which involves lots of upgrading.

Upgrading makes a unique sound effect, that makes it very noticeable if you opponent is upgrading things, if you're paying enough attention.