I am going through the upgrading 1-50 (let's say M0). Once I reach 50 I understand I have basically M1, even if it will be shown as M0 fully updated. Fine, but can I keep upgrading another 50 levels to reach M2? From the answers given earlier, it seems to me that once reached the 50th upgrade some buttons (or choices) disappear and you are forced to buy, not next, but after next model (obviously whenever rank and crystals requirements are reached).
Customer support service by UserEcho