At times when we develop new features or functionality, we gradually "turn it on" to ensure a smooth transition and minimal impact for users. Instead of one big sudden change, we are able to control with the configuration aspects of the functionality that make it more or less intrusive to the user. This is all done in the same release/version of the software, so no software development changes are required (unless bugs turn up that need to be fixed).

For example, initially we may only perform logging or analysis of data without acting upon it. Or we make something optional for a period of time before it becomes compulsory. The idea is that this reduces the potential for problems either on the technical side as well as unexpected changes by the user.

The question is, is there a formal name for this approach?