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...
Firstly check if your sim is 4G enabled. In your message box sms 4G to 131. If it confirmed that your sim is 4G enabled. Follow these step
Select Settings.
Select Mobile Data...
