If a new 28 node is started with auth, you have to create a “restore” user to do the restore, but creating a new user also creates the “authSchemaVersion” document "5", which conflicts with the one in the dump and causes a duplicate key error when restoring.

1. The restore tool should not restore the authSchemaVersion if its already on the server but simply restore the users.
2. In order to maintain compatibility the restore tool should not restore a dump file with authSchemaVersion <3 or to a server with authSchema <3.