When Properties were introduced in AC20, the recommended method of Scheduling changed from Parameters to Properties. For some reason, they changed the AC20 Doors to omit many of the "Custom" Parameters that are no longer needed. However, this Migration would have disabled many old Door Schedules. Therefore, the Library Manager does not Migrate any doors prior to AC20 (AC19 would work, though), and simply loads in the Migration Libraries to keep the old Door Library Parts.
Chuck Kottka
Orcutt Winslow
Phoenix, Arizona, USA
ArchiCAD 25 (since 4.5)
Macbook Pro 15" Touchbar OSX 10.15 Core i7 2.9GHz/16GB RAM/Radeon Pro560 4GB