In Exchange Server 2010 SP1 is was possible to create a hosting specific implementation by using the /hosting switch during setup. The /hosting implementation is discontinued by Microsoft and replaced by Address Book Policies in Exchange 2010 SP2 and the Address Book Policies solution is continued in Exchange 2013.
If you are running Exchange 2010 SP1 /Hosting and want to upgrade this the latest Service Pack (SP3) this is still possible (and supported!) but you have to use the unattend mode of the setup application. Use a command similar to this:
Setup.com /mode:upgrade /hosting
Please be aware that you have to upgrade your CAS servers first, followed by the Hub Transport servers and the Mailbox servers. Also take care about the CAS Array and the DAG. More information regarding the upgrade process can be found on the following Technet article:
Upgrade Exchange 2010 to Exchange 2010 SP1, Exchange 2010 SP2, or Exchange 2010 SP3 – http://technet.microsoft.com/en-us/library/bb629560(v=exchg.141).aspx