Import Groups in Downgrade Protection 
An import group comprises transport requests that are imported to the same production system, in the same sequence as they were released. When the same object is changed in different transport requests that belong to the same import group, the system does not treat this as a conflict, since there is no potential downgrade risk.
Import groups are used by the following downgrade protection checks when dealing with conflicts:
Cross-system object lock
Release check
Reassign check
Features
Transport requests belong to the same import group when the following prerequisites apply:
Two transport requests in the same normal change or defect correction that are on the same transport track
Two transport requests in the same QGM change or QGM urgent change that are on the same transport track
Two transport requests in the same urgent change
NoteTransport requests in the same urgent change are always imported into the same production system from one development system. There cannot be two transport tracks in an urgent change.
End of the note.
In all other cases, two transport requests belong to different import groups, for example:
Two transport requests created from the same task list
Two transport requests in the same normal change that are on different transport tracks. They can be imported separately into the production system by transport track, using the CTS project ID.
One transport request in a normal change and another transport request in an urgent change. They can be imported into the production system independently.
Two transport requests in different urgent changes since they can be imported into the production system independently
Two transport requests in the same QGM change that are on different transport tracks. They can be imported separately into the production system, by transport track, using the CTS project ID.
Two transport requests in different QGM changes. They can be imported into the production system independently.
One transport request in Change Request Management and another in QGM. They can be imported independently.
Note
Two transport requests created from the same task list can be on the same transport track. In this case, they will not cause a potential downgrade, but they are still in different import groups. This allows for conflict reporting for task list-only use cases.
The import group function does not prevent downgrades caused by selective imports. You can use the downgrade protection import check for this purpose. During the selective import, downgrade protection may report new conflicts that were not reported when saving or releasing transport objects.