[from Office New Blog]
We'll release Service Pack 1 (SP1) for the 2013 set of products including Office, SharePoint and Exchange. SP1 will deliver performance enhancements, feature updates and improve compatibility with Windows 8.1. Of course if you're an Office 365 customer, you're always up to date with the latest versions of our products. We'll have more details to share on all that is coming in SP1 and how customers can acquire it closer to availability.