Mtn sim upgrade is like a sim swap
You must drop your old sim
And put new one they give in Mtn shop or Mtn office
When u do that if still showing you 3g go to settings on...
Hi Frank, Kindly visit any MTN outlet with your NIN/NIN slip to upgrade your line to 4G. You will receive free 4GB LTE data bonus upon successful upgrade and the bonus is valid...