How to change the lockscreen themes?

[dula714]

I tried looking everywhere and I cannot find it.

I am talking about this:
Cortana (yes!) and Many, Many Other Great Features coming in Windows Phone 8.1

FYI: It is under "Lock screen: Lots of new ?themes? to choose from"

 

[Promaker]

I read somewhere that the feature won't be available yet since it needs the certain app (by Microsoft and Rudy Huyn?) to make it work. The source was possibly Joe Belfiore's tweet, not sure though. And yeah, I don't know if it will be available when WP8.1 is officially released or just when they finish it. Later anyway.

 

[Jorlon]

Its been said that the app will be released at a later time

Windows Phone 8.1 Developer Preview won’t include lock screen theming appTechie News