Carrier/PLMN selection while roaming – API or entitlement for carrier apps?

Hello,

I am investigating a roaming network selection use case on iPhone and would like to know whether Apple provides any supported API, entitlement, carrier capability, or carrier-specific integration that allows an application or a mobile network operator to access or control PLMN selection while roaming.

My specific use case is:

• Device: iPhone 17
• iOS: 26.6.1
• Home operator: Orange France
• Roaming country: Switzerland
• Automatically selected roaming network: Salt
• Preferred roaming network: Swisscom

At this location, Salt has very poor cellular coverage while Swisscom has excellent coverage. The user can manually select Swisscom through:

Settings → Cellular → Network Selection → Swisscom

I would like to determine whether there is any supported mechanism for a carrier or a carrier-authorized application to:

1. Read the currently selected roaming PLMN.
2. Obtain the available roaming PLMNs.
3. Programmatically select a specific PLMN.
4. Configure a preferred roaming PLMN.
5. Ask the modem to prefer one roaming partner over another.
6. Access any carrier-only/private entitlement that provides such functionality.

For example, could an authorized Orange carrier application or carrier integration request that Swisscom (MCC 228 / MNC 01) be preferred over Salt (MCC 228 / MNC 03) while roaming in Switzerland?

I understand that Core Telephony provides access to some carrier information and that certain capabilities require Apple-granted entitlements.

If this functionality is not available to third-party applications, is there a carrier integration, carrier configuration, SIM/eSIM profile mechanism, or other Apple-supported mechanism that can influence the preferred roaming PLMN?

I am specifically looking for a supported solution and not a jailbreak or other unsupported/private API.

Thank you.