Halo 4's significant upgrades to its multiplayer mode includes the revamp of competitive multiplayer, now known as War Games, and the addition of a dedicated co-op campaign in the form of Spartan Ops.
Each of these modes allows participating Spartans to upgrade their gear and modify their loadouts. Each support upgrade is an ad-hoc technology-based enhancement to the Spartan's armor functionality, providing augments for combat resiliency in firefights and a variety of combat scenarios.
Here are the support upgrades available to use in Halo 4.
Ammo Upgrade
The Ammo Upgrade overrides Mjolnir armor limitations and allows Spartans to carry ammo counts exceeding the recommended amount while in the battlefield. The upgrade comes highly recommended for close quarters specialists and provides its users with a large amount of ammunition to burn through.
Sensor Upgrade
The Sensor Upgrade increases the range and sensitivity of the standard motion sensor, making it much more versatile for use in stealth and infiltration operations.
Resupply Upgrade
The Resupply Upgrade allows you to salvage grenades from the bodies of dead players. You won’t be able to do that without this upgrade.
Mobility Upgrade
The Mobility Upgrade provides you with the ability to sprint indefinitely without ever running out of stamina.
Awareness Upgrade
The Awareness Upgrade facilitates minor adjustments in the HUD to integrate the default motion sensor into all scoped weapons—both native and exotic. Snipers and long-ranged specialist rely on this upgrade to provide them with motion sensor data while sighting enemies from afar.