Upgrade Center lvl2
Unlock devices and weapons lvl4.

Upgrade Center lvl3
Unlock devices and weapons lvl5 and lvl4. Another upgrade center lvl2 isn't needed.
Need another upgrade center to build it.

Improved Munitions Plant
Unlock lvl5 2nd upgrade (blue) of the listed weapons/munitons in game. Another munitions plant isn't needed.
Need upgrade center to build it.
Unlocked upgrades can be built 2 times.

Improved Factory
Unlock lvl5 2nd upgrade (blue) of the listed weapons/munitons in game. Another factory isn't needed.
Need upgrade center to build it.
Unlocked upgrades can be built 2 times.

Advanced Munitions Plant
Unlock red upgrades of the listed weapons/munitons in game.
Need munitions plant or improved munitions plant and a lot of space to build it .
Unlocked upgrades can be built 1 time.

Advanced Factory
Unlock red upgrades of the listed weapons/munitons in game.
Need factory or improved factory and a lot of space to build it.
Unlocked upgrades can be built 1 time.