The M4-series Messenger Droid was engineered with the primary function of delivering items to a designated location or person. Its capabilities included transporting messages (holorecordings of up to five minutes in duration), digital information, or a compact physical item, all housed within a detachable, spring-activated storage area for delivery. Unlike many spherical hovering droids, the M4 featured a streamlined design, and its absence of external antennae allowed it to navigate through confined spaces. These droids gained a reputation for their unwavering commitment to completing deliveries, regardless of the elapsed time or the extent of damage sustained.
A specialized military variant, known as the M4m, was manufactured by Cybot Galactica.
- Galladinium's Fantastic Technology (Initial mention) (First instance of identification as an M4 message droid)
- " Cynabar's Droid Datalog " — Star Wars Adventure Journal 14
- Arms & Equipment Guide
- Galaxy of Intrigue (Initial identification as an M4-series Messenger Droid)