I have a Samsung phone and received the email about the network upgrade with instructions to order the new sim card. My friends who have iPhones did not get an email. If someone has an iPhone or a phone with an e-IMEI is visible handling their upgrade automatically so there's no action for them to take?
From what I have been seeing about the emails is that it appears that Visible might be sending out the notifications in block as it seems like some are getting them and this upgrade option. I never actually got the email but saw it the day it came out on my account page on February 2nd or 3rd. I requested a card before I even got the email.