The growing amount of complex Software and rapid changing of today’s information systems environment requires structured methods for development and maintenance. Renewing of systems is a time-consuming and demanding process, caused by grown structures. In the range of industry-automation, because of long operation times of systems and the reuse of software for reasons of economy, software modernization is necessary. A lot of technical and business related changes occur. Each change might be complex and of various impact for the running systems.
The fundamental property of industry-automation systems is the complex and tight interaction of technical processes, hardware and software. Constantly high requirements related to security, reliability and real-time behaviour exist.

At first, the documentation of such complex systems is extended to a variety of interconnected models. Analysis based on models is to reduce a better orientation and system understanding for new employees. This is necessary because of irregular change-cycles.
Long term goals are an improvement of quality and shorten development-process by an increased usage of models.

Research is supported by Eckelmann AG and supplied with scenarios from practice.
Based on real-live systems, strengths and potentials of model driven software-modernization are highlighted just as its problems and limits.