Digital Applications are complex software systems for decision support in process operations and for process control. Each such application involves one or more computational modules being executed in an arbitrary real-time schedule, and communicating with each other and the external environment within which they are deployed. Each module may involve a mathematical computation based on a process model derived from first-principles or via machine learning applied to plant data; alternatively, it may have a purely statistical basis derived directly from plant data. There has been much progress in the use of such digital applications in industrial practice. However, achieving true scalability and sustainability in this direction will require general platforms that will allow the essentially code-free development of new applications and their large-scale deployments. We describe one such, recently developed, platform. We also consider the potential role of digital applications in the context of major trends in process operations, such as autonomous plant operation and process plant modularization.