Strategies for Replacing Systems in Agile Projects

Abstract

In replacement projects one of the biggest questions is what strategy to use in replacing the old system. The simplest strategy is to wait until the new system is “at least as good as the old one” before switching. Although this strategy sounds compelling it has many serious drawbacks. An alternative strategy is based on what I call a “Minimal Deployable Entity”. Switch systems when you have just enough to be able to survive with the new system. The concept is similar to “Minimal Marketable Feature” but more focused on deployment strategy. This paper uses two projects as concrete examples of patterns and principles that can be used to define a strategy for a Minimal deployable entity.