4g to 5g upgrade

[Andy0609]

I have received my new S21 ultra 5g, will I need to use the sim that came with it, or can I simply use the sim from my s9 plus 4g?

[Bambino · Accepted solution]

@Andy0609 You will need a new 5G sim. If one didn't come with the new phone you can call customer service and ask for one to be sent. You will then need to do a sim swap: SIM Swap: a mini guide (incl eSim) - O2 Community

Alternatively, you can call into an O2 store if you have one nearby and they will give you a new sim and do the swap for you.