We are still developing mojoPortal and are working on a release right now. We tend to go a while without releasing anything but we are always improving mojo in many different ways.
As for an MVC version, the original developer of mojoPortal did decide to start a new project and originally he was planning on making some kind of an upgrade path to it from mojoPortal. His new project was acquired a while back by another company and he never built any kind of migration path. The new project is less of a content management system and more of a collection of separate packages that do different things and one could build a CMS with them. It's good stuff for sure but it doesn't really replace mojoPortal in a lot of ways.
We are in the early stages of planning and have done some development on a new CMS based on MVC and .NET Core that will be an upgrade from mojoPortal. We don't have a lot of information that we're willing to share publicly on it yet though. It will definitely be Open Source.