The Nexus of Forces (information, mobile, social and cloud computing) creates new, disruptive demands for enterprise IT. As a result, the old monolithic or nearly monolithic two- and three-tier application architectures fall short of the required extensibility, versatility, scale and agility of applications, and must be replaced with the agile and extensible nexus-enabled application architecture principles — in order to meet new IT services demands.

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While most organisations already engage in one or several of these forces, the true breakthrough comes to those that are able to tap into the combinations of these forces and tie them to their core enterprise computing base.

The key to the synergy lies in application architecture that is aware of the new business demands for IT services and is enabled to meet them.

Of all the advanced application architecture principles, the fundamentals of service-oriented architecture (encapsulation, separation of concerns and loose coupling) emerge as essential if the organisation is to adopt the digital business mode of operations and the Nexus of Forces as an engine of its empowerment, and create agile applications that are enabled to function effectively in its context.

While the modern application architecture principles (service and data encapsulation, systematic separation of concerns, application of event-driven and request-driven communication models, loose coupling, intermediation and instrumentation for governance, cloud-first/mobile-first design targeting) should be applied on all new applications, it is important to note that many older systems cannot be converted to a modern form quickly (and in some cases — ever).

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Some will come up for maintenance because of the changing business processes, others because of the need to refurbish their technology base for better performance, and some will simply become obsolete and be scheduled for replacement. However, organizations need to realise that applications created or refurbished in 2014 — using the old architecture models — will be an IT-constraining legacy by 2016.