New iPhone 6s. They sent a new SIM too. Do I have to swap?

[JemTheWire]

As the title says really. 

I already have an iPhone 5s on an existing pay monthly contract with O2.

Today I recieved my shiny new iPhone 6s. Also in the package was a new SIM card. My question is, do I have to swap my existing SIM with this new one?

Both are the same size (physically) so will I suffer any issues 'down the road' if I don't use the new SIM?

Thanks. I have tried the O2 Chat, but no one is available.

[MI5 · Accepted solution]

As long as you did an upgrade you can use the old sim card.

[JemTheWire]

Thanks. That was quick.

Yes, it was an upgrade.

[MI5]

You'll be fine then mate..
Keep it as a spare, just in case !

[Anonymous]

Help. Got my new iPhone 6s as an upgrade from my old 3GS . Tried to set it up but it keeps freezing and won't work. Anyone else having problems? My old phone now has no service and my new phone doesn't work.

[Cleoriff]

Hi @Anonymous Did you get a new sim with the phone? You may need to do a sim swap...

http://swapmysim.o2.co.uk/

[MI5]

If it's faulty call cs http://www.o2.co.uk/contactus and arrange a replacement.