Not sure what you mean. The game isnt downloaded from Subscribestar.
I dowloaded the game from here and A lot of stuff are blocked by WIP sign. ... Work In Prorgess, so I assummed that to acess this unfinished content you had to be a tester and paid a special tier on substar or something...
Also aside from new extra training, I don't see the new content. I can't finish the quest I started at the library, I can't get new levels I am still stuck at 10 because I don't get to fight new monsters and the secret boss.. Well I either die or disapoint her just like in previous update.
She isnt a secret boss. You need to "defeat" her to progress in the story.
All I can say without spoiling is keep an eye on your"Status icon" during battle and change the way you act accordingly. If you wish to know directly how to defeat her. Please ask in the Spoiler topic: https://dmquetzalli.itch.io/delve-into-pawssion/devlog/382260/guides-and-secrets...