I just came across the following reference to the Mendix Teamserver: "a very useful extension to the Business Modeler for multi-user and distributed development teams. Includes versioning, testing, reporting and advanced deployment capabilities." on a link to a web page which has recently been removed. Does this stll/did it ever exist? I'm assuming it's no longer available.
We recently moved to a new corporate website. That's probably the reason for the removal. It sounds like an outdated page, though.
It is possible to use the current Modeler version (2.4.x) as a multi-user environment. You have to select PostgreSQL or SQL server as model repository when opening or creating a project.
We are currently working on an innovation in this space. We cannot disclose any details at this time but keep tracking our website for any updates.