With the availability of powerful computers and software, mathematical modelling, simulation and optimisation (MSO) has developed into a key technology of the 21st century as a central methodology of scientific computing. Modern model-based methods of simulation and optimisation open up new possibilities for understanding and optimising real processes. This has not only changed academic research. MSO has also become indispensable in numerous industrial and societal areas as a key to innovation. Applications range from a better understanding of the dynamics of cancer to the optimisation of combustion processes and the efficient control of renewable energy networks. The aim is to further develop existing software packages in a targeted manner with regard to sustainable usability. By means of "best practice" strategies to be established, it is to be ensured that current and future scientific software development also benefits from this.