We must support legacy products when upgrading projects into a new system. The goal is to allow information transferred into the new project, but rebuild the project plan with only the new phases that support timeline template.
The solution is to display the legacy products as manager/copilot read-only phase where in the Timeline tab we'll display a message (@acshields we'll need your help on language). Something in the lines of "We transfer this phase as a read-only from a legacy project. It is visible only to managers and copilots. Please use the phase catalog to add the appropriate phase with a timeline bellow."
Legacy products should not be visible on the phase catalog.
Aha! Link: https://topcoder.aha.io/features/TCCONNECT-425