Do to unforseen circumstances the Atelier build that was distributed with the Cache 2016.2 field test had certain incompatibilites which prevented it's effective use with the server that it was bundled with.
The object and relational data models of the Caché database support three types of indexes, which are standard, bitmap, and bitslice. In addition to these three native types, developers can declare their own custom types of indexes and use them in any classes since version 2013.1. For example, iFind text indexes use that mechanism.
This is a nice introductory explanation of MQTT that I thought would be of general interest. The technology used for the broker in this case is not that important as there are several brokers available.