Sorry for the late answer. Yes, EX version is exclusive to the Patreon at the moment. Initially, I planned to use it for distribution platforms like Steam and Nutaku since it’s pretty silly to push a public version to them.
Yet this plan failed due to several unforeseen requirements from Nutaku and Steam needs a movie for the shop. Most likely I will try to prepare everything I need for Steam while forfeiting Nutaku. They want about 1/4 of scenes changed or cut which is a problem. Can’t provide any estimated dates.
In short, grab the public version and if you decide that you like it enough to say “thanks” - get the EX via Patreon because I can’t say when Yorna will make it in Steam.