Originally released in April 2014, Microsoft has released an update to the Microsoft Remote Desktop Preview for Windows Phone 8.1 to bring it to version 8.1.3. The updated version will be available in the Windows Phone store shortly and delivered to preview users at that time.
The latest update brings some fixes, but there are couple specific features that users of the app should immediately find interesting.
First off, Cortana is now integrated, allowing you to simply tell Windows Phone's digital assistant to "remote desktop <computername>." Microsoft is interested in any additional Cortana features you'd like to see in upcoming refreshes. You can submit a feature request here: http://aka.ms/rdwinphone
One additional change included with the update is to stop Windows Phone from locking while connected to a remote system – which sometimes can actually end the remote communication. This is added as a selectable option in the app for those that would rather not leave the connection open when they walk away and leave the smartphone lying around.
The Remote Desktop app is available from the Windows Phone store here: Microsoft Remote Desktop Preview