So it looks like KFC has removed the ability to do this in the app but conveniently if you do this in the in store touchscreen order kiosks it still works.
Important now just in case your app doesn't give you your KFC in July deal.
Steps for those who haven't done it yet:
- Add a large shared meal to your order (anything ending in "Feast")
- On the next screen that pops up, choose to add 4pc Original or 6pc Hot & Spicy for $7.45
- Go to your cart and remove the feast from the order
- Checkout the order
Edit: It looks like if you do this in the app and customise the pieces (e.g. change the original recipe to Hot&Spicy) that the hack works for the app still!
Stopped work in store and on app.