Shortly after PureMVC’s release, the largest requested change that had not been originally scoped was implemented: the MultiCore version.

Since there can be only one instance of each of the Facade and Core actors, a powerful feature of the Flash Platform was difficult to work with: Flex Modules or loaded Flash SWF files that were themselves using PureMVC.

Imagine a truly modular design decoupled enough that it could accommodate third party PureMVC-based modules running together in a PureMVC-based host application. Unless the module writer has access to the host code, Notification naming collisions could occur, thereby causing unstable behavior.

The solution to the problem was to allow for separate sets of the Facade and Core MVC Singletons for the host and each module. They become Multitons now: registries of named instances rather than holders of a single instance. Each core could then run as a whole separate program.