SYSE.27:2 - Problem

An interface can keep the same spelling while its units, defaults or failure behavior change. A new template can work for its author and break a consumer’s unexercised variant. Conversely, requiring the central provider to implement every variation can suppress useful specialist contributions and encourage unmanaged forks.

The recurring task is to choose how the proposed contribution can enter the provision while preserving or deliberately changing the promises on which other users rely.