Hi plokijuhygtf901,
I think a lot of players are getting trapped here (I got trapped as well when I replayed the version 11 events using version 12 of the game), because there are a couple of minor bugs in the game that make it impossible to advance. So I'll give detailed instructions to help the others as well.
To fix things, you'll have to enter the developer's console (press SHIFT-O), and enter the following lines:
joye_bath_24_1 = 5
linsay_model = 0
linsay_talk = 3
exit
The first change allows you advance with photoshoots with Joye, starting at midnight (this is due to a bug on line 3166 of studio.rpy). The last two changes allow you to start swimming lessons with Linsay. DO NOT GO TO THE DINING ROOM BETWEEN 16:00 and 18:59, even though the mod suggests you should. Instead, go to the guest room on weekdays at noon. Do this two days in a row. The first time select "Walk in" and "Untie her panties". The next day select "Walk in" and "Don't untie her panties". Now you can go to the dining room between 16:00 and 18:59. You'll talk about modelling with Linsay. Now jump back into the console (SHIFT-O), and enter:
linsay_talk = 3
exit
Go back to the guest room on a weekday at noon and select "Walk in". This should trigger event a11_28 and get you back on track (this is due to a bug on line 765 of guest_room.rpy).
Let me know if you still have problems.