In the past couple of years, there was a big issue when you swap SIM cards from one carrier to another where as iMessage stopped working or you did not get the activation email. This happen even when you swap back the old SIM card. Example: https://support.apple.com/en-gb/HT204270 http://toomanyadapters.com/imessages-switch-sim-cards/ http://blogs.wsj.com/personal-techn...ssage-can-cause-problems-for-phone-switchers/ I am planning to move from T-Mobile to Verizon but will be doing testing first, so what I'll be doing is: 1). Swap out my T-Mobile SIM card and replace with Verizon Pre-paid SIM card 2). Test 3). If work, swap out Verizon Pre-paid SIM card with Verizon Post-paid SIM card Does anyone know if the iMessaging issue still happening? If not, what is the proper steps to activate/deactivate iMessage with different SIM cards?