A directory synchronization has been setup without specifying Exchange options and the synchronization is in delta sync mode. Later it is decided to enable the email options for an upcoming Exchange migration. Will this pose a problem? What will happen?
After a directory sync was in delta mode, you can still add the Exchange options to the sync, however this will force a full resynchronization of the directory. All accounts will be matched again, and will be mailbox enabled on the target as normal. There is no "harm" in doing this.