Microsoft officially revealed Windows Phone 8.1's first update yesterday, though some questions remained about how users of the Developer Preview would upgrade to get the improvements. According to Microsoft's Joe Belfiore, an executive on the Windows Phone team, those users won't have to actually do anything.
Responding to a user who asked if he'd have to downgrade and then install the Developer Preview again, Belfiore said the update will automatically be pushed out to smartphones in the preview program. As Microsoft announced yesterday, the update will come to Developer Preview users sometime next week, though an exact day has yet to be announced.
@CamdenKrupala if you're on WP 8.1 DP right now, you don't need to do ANYTHING and you'll automatically get 8.1 Update 1 next week.— joebelfiore (@joebelfiore) July 31, 2014
Windows Phone 8.1 Update 1 is slated to bring several small but requested changed, such as the ability to combine apps into a single tile grouping and a new live tile for the Windows Phone Store. Many of the new features will be specific to certain regions, as Microsoft pushes Cortana specializations out to new markets such as China and the U.K.
Source: Joe Belfiore (Twitter)