At the end of last year, Microsoft officials shared a partial list of what would be included in Exchange SP1. Those features include support for Windows Server 2012 R2; support for S/MIME in OWA will be brought back in SP1 (With SP1 customers will have S/MIME support across Outlook, Exchange ActiveSync clients, and OWA); and inclusion of the Edge Transport server role.
The SP1 updates for the Windows Installer (MSI) versions of the Office 2013 desktop products and SharePoint 2013 Server available from the Microsoft Download Center, Windows Update and WSUS starting today. After a 30-day period, SP1 will begin releasing as an automatic update through Microsoft Update, Microsoft officials said. For those with Office 365, Microsoft will be including the SP1 changes automatically in their next regular update, Microsoft execs said.
Update: Microsoft also is making updates to Office RT (the version of Office that's bundled with Windows RT) available today, as well. Users will get the SP1 features via Windows Update starting today, a spokesperson said. Project Server also is getting SP1 updates today, too.