Square Enix has announced that an updated version of the Final Fantasy XV demo Episode Duscae will be coming in early June.
Called Final Fantasy XV Episode Duscae 2.00, improvements listed by Dengeki are frame-rate stabilization, camera control, some battle modifications, combination attacks, bug fixes, and balance. The popular Japanese media outlet cites Square Enix's Active Time Report as the hint for these predicted tweaks.
Presumably, those with the current version will simply choose to update. If the demo suddenly becomes available to the public, against what Square Enix had previously said about the demo's availability, we'll let you know.
I totally played this, but it was a long time ago. I should go back and check it out again. You?