Replacement project
Any project that will lead to the phasing out of one or more systems. Most replacement projects have multiple goals and will also develop new features. Examples of systems that are replaced in replacement projects range from "ancient" legacy systems to outdated content management systems on web-sites.
It is also interesting to note that there are many similarities between projects that are developing new products that will compete with existing products and replacement projects.
Replacement projects are closely related to Enhancement projects and can use many of the same Principles and patterns.