Courier droid
Courier droids, which are also referred to as messenger droids, represented a type of droid designed for the physical transportation of communications from one area to another. A number of different messenger droid designs were produced, such as the ASN courier droid and the KUP24 messenger. The Galactic Empire utilized modified versions of the R4-series astromech droids as courier units.
Models
Throughout the galaxy, various types of messenger droids existed, all created to serve the function of transporting data. The ASN courier droid was a small, flying droid that stood 0.3 meters tall and included a small container for carrying messages. However, these droids could also be altered to act as assassins, delivering dangerous materials from their message containers.
The KUP24 messenger was a compact, flattened design utilized by the Pyke Syndicate under conditions of enslavement within the Spice Mines of Kessel.
MSE-6 series repair droids, typically called mouse droids, were small, wheeled, general-purpose labor droids with black plating that, among other duties, transported communications across military facilities.
The Imperial Press Corps of the Galactic Empire made use of modified R4-series astromech droids as courier droids in order to transport confidential information between distant locations while avoiding network communications. The Empire specifically programmed these R4 courier droids to lack any personality and provided them with unique markings to indicate their function as couriers.