Scheduled Service Change: Postoffice and Webmail Retirement
None, they've all been migrated to Exchange
There is no workaround for this issue
Shutdown and decommission Postoffices6-10, Hermes21, and Slate. The Postoffice's users have all been migrated to Exchange and the mailboxes will of completed the 35 day expiration by that date. Hermes21 and Slate were used in the support of Webmail (aka Squirrelmail) in conjunction with the Postoffices.