For software vendors the processes of release, delivery, and deployment to customers are inherently complex. However, software vendors can greatly improve their product quality and quality of service by applying a model that focuses on customer interaction if such a model were available. This paper presents a model for customer configuration updating (CCU) that can evaluate the practices of a software vendor in these processes. Nine extensive case studies of medium to large product software vendors are presented and evaluated using the model, thereby uncovering issues in their release, delivery, and deployment processes. Finally, organisational and architectural changes are proposed to increase quality of service and product quality for software vendors.