During migration, the program updates project or drawing-level data. For example, it changes point parameter names to support end-coded valves, or adds To/From properties for pipe line segments.
Migration can be time-intensive, depending on how large a project is or how many drawings are associated with the project. Once the migration is complete, you can work on the project and its drawings.
When you open a project created in an earlier version, the Project Migration wizard starts. It displays the Project Migration Launch dialog box. During the migration process, you can backup the project and associated drawings. A backup ensures that the project still opens in the earlier version. If you cancel the migration process, the project and its related files return to their original state.
Configuration: 
Migrating Projects Specs Catalogs.pdf (pdf).