On completion of the migration process "Unread" mail status flags change to "Read".
Issue fixed in GroupWise Migrator for Exchange (now Migrator for GroupWise) version 126.96.36.199 and later versions. The Administrator Driven Batch Migration and Self-Service Desktop Migration modes now preserve server-mail Read/Unread status after migration via the password-access and trusted-API methods, when migrating from a GroupWise source version 6.5.1 or higher.
For the Most up to date version of MFG (Migrator for GroupWise) please go here.
Limitation: Unread mail status still cannot be preserved with the AddProxy method, as Groupwise APIs do not support it with the AddProxy method.