This paper presents an update on improvements to the generic system of plant-wide impurity balance models (IBMs) discussed in the last International Alumina Quality Workshop (Riley et al. 2002). Following the successful initial global deployment of the Alcoa plant-wide model, to ensure ongoing support from the software vendor, we have converted the original models to a new platform. In the process, these converted models have been further enhanced, not only to include precipitation yield prediction but also inclusion of a number of important improvements in knowledge of Bayer process chemistry, and development of a semi-dynamic mode of operation (for modelling effects of lake volume changes). A new model interface system has also been developed as part of the software conversion project. The enhanced Alcoa generic system of plant-wide IBMs has gained significantly wider usage, from regular and advanced model users.