I just tested a little to make sure the SD card fix still works on my Tab S which is still on kitkat. Everything worked ok except the checkmark didn't appear telling me the book was on the device until I went back to the main list and then chose newest again to bring the book list back up. This was using the cloud connection. I had used a long press on the JA Konrath book and when the download was complete no checkmark was visible. When I downloaded by going into book details it worked correctly - the checkmark was there when I returned to the book list.
Edit: I do not have the box checked in settings to use SD cards on kitkat. I never had it checked because it always worked anyway.