Retain was implemented in 2010 to comply with EDiscovery Federal and State laws.

Retain keeps EVERY item from your GroupWise account for 7 years automatically without user intervention. Users just need to set auto-cleanup to delete older emails from your live mailbox.

To set Auto-cleanup from the GroupWise Client:
Tools | Options | Environment | Cleanup tab | auto-delete

Even if you delete an item the day you receive it, Retain will have the item (That is why you cannot empty your trash for any item less than 24 hours old).