IBM Rational DOORS is designed to match paradigms of requirements engineering that matched the state-of-art up to lately 2011. It is still at the top of the list since many engineers have been educated with the paradigms in mind. But as can be already drawn from the name there is a mismatch in concepts that have developed bigger since. This is a package from the broader IBM Rational software suit. This emphasizes the Rational Dynamic Object Oriented Requirements System that has been extended by the DOORS eXtension Language (DLX). In the selling logic of IBM, it is superseded by IBM Jazz. For many of my customers, it is a hybrid between knowledge management and lifecycle management. It is important that it is bound against several trusted and approved engineering databases. These are sources of unmatched quality still despite contradicting facts. It is still under development and is supported by the IBM expert team. At IBM the product name is now Engineering Requirements Management DOORS. The product is cross-platform. Clients are Windows, servers are Unix. That has advantages and causes problems. The new focus in the development of the product is to be tech-savvy, enhance simplicity and overview, and grow clarity.