Does switching cell-phone providers require carrier update?

[iMore Question]

After switching from Verizon to AT&T....been experiencing problems with the cell-phone. Also getting the pop-up box -carrier update on iphone 6. If I click on the update will it make things worse or better? been experiencing sync issues with Itunes.
Can you help?

Thank you.

 

[kch50428]

The carrier settings update should make your device work better on AT&Ts network. Install it.