To start the new character event, you first need to see Eri's level 3 breakpoint 2. After that, head to the clubroom at the afternoon.
This update does not contain the next Relationship Level Event for Aiko. I tried to pull out something new for this one, something different compared to the rest of the game, but ironically, it turned out too different. It looked like a completely different genre, and that's not what I wanted.