We caught one of the Moto Mods in need of an update. And since we're the sort who just can't let an update go unupdated, we updated it.
The long and the short of it is you'll get a notification that the Mod has an update available, just as you would an app update. A couple taps and a few seconds later, and all is right in the world. No separate apps to install for new software. (Unlike LG's CAM 360 module.) Just simple, intuitive updating.