registration is made with the IMEI or phone number? in a few days it's going to be a full year of my WhatsApp use, mostly on N97, only these last few weeks on N9 - would I have to pay now, or after a full year on one IMEI? ok, I guess I'll be notified by message from WhatsApp server, but - how to deal with the payment, someone had any experiences? EDIT: to be clear - I'll be glad to pay it, just want to be prepared...