I'm an engineer of an Italian full MVNO, when the SIM attachs to the 4G network, the "4G" label is not displayed and on the mobile device I see "LTE".
The italian MNO we are connected explains that Apple maps into his carrier setting the operator parameters (as example the LTE/4G icon) based on the MNC (Mobile Network Code)
We suppose that our MNC (that is 49) is not present in the Apple carrier setting.
How can we communicato to Apple our MNC ?