We currently have cases running on prpc 7.1. We want to upgrade to 7.3 to take advantage of prpc-RDA integration, pega management console and robotic management portal (when that is released as an on-premise install) and pega-cs 360 view. At the moment, for various reasons, we have a zero risk change policy covering our current pega stack so we are not able to upgrade, therefore we are looking at the possibility of setting up federated cases that are defined in 7.1 and created/used/viewed in 7.3. Essentially surface our 7.1 cases in our 7.3 pega-cs 360 view of the customer. Is that possible between prpc versions?

I have also read in the docs (https://pdn.pega.com/federated-case-management/setting-up-and-configuring-federated-case-management-version6) that you must "Set up a Pega Web Mashup Gateway for each system in a federation" is that strictly required as it is now a separately licensed product. As web mashup is the replacement for IAC which is essentially a reverse proxy, would our own implementation of a reverse proxy suffice? Am i missing something? the docs that i have found so far are pretty sparse on why each system in a federation requires a web mashup gateway.