Drones are combat units that accompany your robot and provide it with different kinds of assistance. Each has a unique role-specific ability that cannot be changed. There is a huge variety of benefits you can receive depending on the type of drone and its upgrades.
Drones are now a part of the robot's equipment, and you don't need to pick them separately before deployment: you choose a drone the same way you pick your weapons and modules before a battle. It also means that drones can be upgraded just like any other item in the game.
You can assign only a single drone to a robot, but even this is not obligatory. You can deploy a robot with no drone equipped. To remove your current drone, select it in the robot's equipment roster and press "Change Drone", click the drone again, and press "Unequip" to send it to the inventory.
A drone is fully autonomous and is never controlled by a player. It is automatically deactivated once a robot it's connected to is destroyed. It cannot be damaged, targeted, repaired, or affected by any effects (Lock-Down, Freeze, etc.)
Drones unlock at level 27. You get one starter drone for free once you reach this level.
NOTE: Drones cannot be used with Titans.