Basically, the new 8.1.3 version of the app lets users say "Remote desktop connect to 'Display Name'" in their Windows Phone device, via Cortana, so they can connect to their PC. In addition, the new version will now allow phones to remain unlocked during a remote desktop session. Finally, there are some unnamed bug fixes and improvements in the app update.
Being able to just talk to your Windows Phone to set up a remote desktop session is a small but pretty nice addition to the functions that Cortana can handle and we will likely see more of that in the future. What do you think of adding voice command features to the Remote Desktop app? Thanks to Akhilesh for the tip!