11.1 is accessed ONLY from chapter 10, from the demon route [6.1>7.1>8.1>9.1>10.0>11.1]. To know if you are on the demon route in chapter 10, just check if when you have to choose between three of the characters to be your main love you have Ariel, Zihel and Pin, if not and you get any other character, you are not on the demon route. You can go back to a previous save where you specified being at any x.1, put this information in the saves.
Also remember that there is no patch for humans (11.2 or higher), nor is there a patch for angels (11.3 or higher). Of course there is nothing after finishing 11.1 either, that will come in future patches.