I have an older iphone will it still work with the new sim
I have an older iphone. Will it still work if I swap the sim card from sprint to tmobile?
iPhone 8 Plus
If it is an unlock and SIM free iPhone yes.
Subscribers can take their telephone number with them (also known as number portability) to another provider.
Number portability is handy, you don't have to change anything, you use the same number.
If you use a prepaid or postpaid is not possible.
You must inform Sprint that you want to take your phone number with you to T-mobile.
Sprint will take care of the switch. Informs T-mobile about this.
You must declare on time, and keep in mind that you will not be able to use your number for a few days. This all depends on where you live.
If the SIM format is different, visit or contact your 'new' carrier and request a replacement SIM card, normally it is free.
See also -> How to unlock your iPhone for use with a different carrier
How to unlock your iPhone for use with a different carrier - Apple Support