Disgaea 4 just got a shiny new patch, up to 1.10. It’s 781 MB. Not sure if there are patch notes available somewhere, but the one confirmed detail is that the free HD Asagi DLC, which was released earlier this week, is now 100% functional!
To access HD Asagi, you need to have recruited her into your party first. There is a new event at the Dimensional Guide, where you fight HD Asagi. Then, you can switch from SD to HD Asagi with a 10,000 mana bill. HD Asagi and SD Asagi are mutually exclusive, unlike Archangel Flonne and Fallen Angel Flonne, the premium edition DLC bonus. You have to pass a bill if you want to switch from one form to the other. I’m still downloading the patch (and I’m currently in the middle of a new cycle anyway) so I can’t confirm if the two Asagis share Evilities or Chara World/skill boosts. Common sense points to no, since they do not share the same unique skills.
Anyway, enjoy your new Asagi in hi-def!
EDIT: Most people are confident that this is the “generic DLC activation” patch, so that any DLC released now or in the future will work as soon as you install it.
EDIT2: Corrected how to activate HD Asagi.