It says? 😱 I'm sorry if I missed or mislabelled something and gave false hope. The current maximum strength levels at the end of Update 7 (Girls with Dragon Tattoos) are:
Gina 6
Stella 6
Jade 5
Aline 4
Akari 5
Rose 3
In the next update (College Chaos), Aline and Gina will get their next levels along with a few characters for the arc.
Hope I could clear up any confusion and thanks for the kind words. I'll pass them on to my team.