LevelCap explains all Battlefield 4 field upgrades
Instead of specializations, Battlefield 4 will feature a brand new upgrade and perk system, called Field Upgrades. The field upgrades in the game are based on how well the player and his squad perform on the battlefield. The better they’re doing, the quicker they level up in their upgrade tree.
There are a number of field upgrades available, from extra ammo, to faster sprint, to better armor. These are then grouped in different categories. For example, the "Defensive” field upgrade path starts with extra armor as Level 1, then moves on to reduced suppression at Level 2, to Flak as Level 3, and finally, quicker health regen as Level 4.
Players can chose between 11 different Battlefield 4 field upgrades, each consisting of 4 levels of unlocks. Here is the complete list of the upgrades:
List of Battlefield 4 field upgrade paths
Defensive: Armor – Cover – Flak – Quick regen Offensive: Print – Ammo – Grenades – Reduced Fall Shadow: Quick unspot – Sprint – Reduced Fall – Stealth Combat Medic: Medkit upgrade – Sprint – Defibrillator upgrade – Medical Unit Grenadier: Grenades – Sprint – 40mm grenades – Flak Anti-tank: Mines – Rockets – More deployed explosives – Flak Mechanic: Fast repair – Flak – Cover – Repair unit Indirect fire: Ammo box upgrade – Ammo – Indirect fire – Resupply unit Perimeter Defense: Ammo – Suppression – Claymore – MP-APS upgrade Spec Ops: Stealth – C4 Explosives – Motion sensors – Quick unspot Sniper: Hold breath – Cover – Quick Unspot – Advanced spot
As you can see, some of the most popular perks are recycled between the different upgrade paths, such as sprint and ammo. Players can chose whichever upgrade path they wish, and these will individually progress throughout the match for each player in the squad. However, should the squad be eliminated (all players in the squad are dead at the same time), the field upgrades will reset to level 1.