Method, system and program products for operationally migrating a cluster through emulation

An updating capability updates a component of a computing environment, while maintaining the availability of the computing environment. In particular, a component of the computing environment which is associated with at least a portion of a unit of work is updated from one version to another version. Subsequently, the updated component emulates the original version, or operates in a compatibility mode, while other components of the computing environment, which are similarly associated with the same unit of work, remain at the original version.