Updating the OAB is also possible through the Power Shell console …
via the command As a fallback you can add the Synchronizer users to the addressbook of the Sync User through the OWA (Outlook Web Access).
For Exchange 2013, OAB version 4 supports Outlook client versions from Outlook 2007 upwards.
Figure 1-2: Client Support Options in the Exchange 2013 OAB How the OAB is generated in Exchange 2013 has changed when compared to previous versions of Exchange.
Figure 1-2 shows the details of the OAB properties in Exchange 2013, as retrieved using the Get-Offline Address Book cmdlet and filtering for the Versions parameter.
Here, it can be seen that only version 4 of the OAB is provided.
Something wrong with Schema update or did you mess up the infrastructure.
Restarting the service MS Exchange System Attendant did not even fix this?**Offline Address book data are saved first only on the Organization Mailbox** Then Once its got Updated it Serves the latest data to the Clients How to Force update the Offline Address book Additional Info – Type of Distribution used in Exchange 2013 Exchange 2013 Uses only One Type of Distribution –Web-Based Distribution 1 .