Exchange 2013 Offline Address Book visible after Exchange 2016 deployment?!

After deploying a new Microsoft Exchange organization with Exchange 2016, or after deploying a Microsoft Exchange 2016 into an existing organization, you might notice a strange behaviour regarding the Offline Address Books (OAB).

[PS] C:\Windows\system32>Get-OfflineAddressBook

Name                                    Versions                                AddressLists
---- -------- ------------
Standard-Offlineadressliste             {Version2, Version3, Version4}          {\Globale Standardadressliste}
Standard-Offlineadressliste (Ex2013)    {Version4}                              {\Globale Standardadressliste}

Huh?! Where does this Exchange 2013 OAB come from? As you can see in the cmdlet output, there’s no Exchange 2013 in this organization.

[PS] C:\Windows\system32>Get-ExchangeServer | select Name, AdminDisplayVersion

Name                                                 AdminDisplayVersion
---- -------------------
MAIL-1                                               Version 14.3 (Build 123.4)
MAIL-2                                               Version 15.1 (Build 466.34)
MAIL-3                                               Version 15.1 (Build 466.34)

There is no Exchange 2013 server in this organization. Only Exchange 2010 (Build 14.3) and 2016 (Build 15.1).

This is nothing to worry about. Microsoft has confirmed that this is a bug. The OAB simply has the wrong name and Microsoft will fix it in an upcoming cumulative update. It’s not fixed in the latest CU2 for Exchange 2016! There’s also no need to change the name of the OAB.

So don’t panic, if you deploy a Microsoft Exchange 2016 CU2 and you see “Ex2013” in the OAB name. Ignore it.